1. Obesity Education Initiative
CLINICAL GUIDELINES
ON THE
I D E N T I F I C AT I O N ,
E V A L U AT I O N , AND
T R E AT M E N T OF
OVERWEIGHT AND
OBESITY IN A D U LT S
Th e Evide nce Repor t
N A T I O N A L I N S T I T U T E S O F H E A L T H
N A T I O N A L H E A R T , L U N G , A N D B L O O D I N S T I T U T E

3. CLINICAL GUIDELINES
ON THE
I D E N T I F I C AT I O N ,
E V A L U AT I O N , AND
T R E AT M E N T OF
OVERWEIGHT AND
OBESITY IN A D U LT S
The Ev i d e nc e Re p o r t
NIH P U B L I C AT I O N
N O . 98- 4083
S E P T E M B E R 199 8
N AT I O N A L I N S T I T U T E S
OF H E A LT H
Na tiona l Hea r t , Lu n g ,
a nd Blood Insti tu te in
c oop era tion wit h
The Na tiona l In s titu te o f
Dia betes a nd Dig es tive a n d
Kidney Disea ses

4. NHLBI Obesity Education Initiative
Expert Panel on the Identification,
Evaluation, and Treatment of
Overweight and Obesity in Adults
F. Xavier Pi-Sunyer, M.D., M.P.H. William H. Dietz, M.D., Ph.D.
Chair of the Panel Director
Chief, Endocrinology, Diabetes, and Nutrition Division of Nutrition and Physical Activity
Director, Obesity Research Center National Center for Chronic Disease Prevention
St. Luke's/Roosevelt Hospital Center and Health Promotion
Professor of Medicine Centers for Disease Control and Prevention
Columbia University College of Physicians and Atlanta, GA
Surgeons
New York, NY John P. Foreyt, Ph.D.
Professor of Medicine and Director
Diane M. Becker, Sc.D., M.P.H. Nutrition Research Clinic
Director Baylor College of Medicine
Center for Health Promotion Houston, TX
Associate Professor
Department of Medicine Robert J. Garrison, Ph.D.
The Johns Hopkins University Associate Professor
Baltimore, MD Department of Preventive Medicine
University of Tennessee, Memphis
Claude Bouchard, Ph.D. Memphis, TN
Professor of Exercise Physiology
Physical Activity Sciences Scott M. Grundy, M.D., Ph.D.
Laboratory Director
Laval University Center for Human Nutrition
Sainte Foy, Quebec University of Texas
CANADA Southwestern Medical Center at Dallas
Dallas, TX
Richard A. Carleton, M.D.
Professor of Medicine Barbara C. Hansen, Ph.D.
Brown University School of Medicine Professor of Physiology
Pawtucket, RI Director of Obesity and Diabetes Research Center
University of Maryland School of Medicine
Graham A. Colditz, M.D., Dr.P.H. Baltimore, MD
Associate Professor of Medicine
Harvard Medical School Millicent Higgins, M.D.
Channing Laboratory Department of Epidemiology
Boston, MA School of Public Health
University of Michigan
Ann Arbor, MI
ii

5. James O. Hill, Ph.D. Albert P. Rocchini, M.D.
Associate Director of Research Chief of Cardiology
Center for Human Nutrition University of Michigan Medical Center
University of Colorado Health Sciences Center Ann Arbor, MI
Denver, CO
Philip L. Smith, M.D.
Barbara V. Howard, Ph.D. Professor of Medicine
President Division of Pulmonary and Critical Care
Medlantic Research Institute Medicine
Washington, DC The Johns Hopkins Asthma and Allergy Center
Baltimore, MD
Robert C. Klesges, Ph.D.
Professor Linda G. Snetselaar, Ph.D., R.D.
University of Memphis Prevention Center Associate Professor
University of Memphis Head of Preventive Nutrition Education
Memphis, TN Department of Preventive Medicine
University of Iowa
Robert J. Kuczmarski, Dr.P.H., R.D. Iowa City, IA
Nutrition Analyst
National Center for Health Statistics James R. Sowers, M.D.
Centers for Disease Control and Prevention Professor of Medicine and Physiology
Hyattsville, MD Director
Division of Endocrinology, Metabolism, and
Shiriki Kumanyika, Ph.D., R.D., M.P.H. Hypertension
Professor and Head Wayne State University School of Medicine
Department of Human Nutrition and Dietetics University Health Center
The University of Illinois at Chicago Detroit, MI
Chicago, IL
Michael Weintraub, M.D.
R. Dee Legako, M.D. Director
Prime Care Canyon Park Family Physicians, Inc. Office of Drug Evaluation V
Edmond, OK Food and Drug Administration
Rockville, MD
T. Elaine Prewitt, Dr.P.H., R.D.
Assistant Professor David F. Williamson, Ph.D., M.S.
Department of Preventive Medicine and Epidemiologist
Epidemiology Division of Diabetes Translation
Loyola University Medical Center Centers for Disease Control and Prevention
Maywood, IL Chamblee, GA
iii

6. G. Terence Wilson, Ph.D. Van S. Hubbard, M.D., Ph.D.
Oscar K. Buros Professor of Psychology Director, NIH Division of Nutrition Research
Director, Rutgers Eating Disorders Clinic Coordination
Piscataway, NJ Chief, Nutritional Sciences Branch
National Institute of Diabetes and Digestive and
Kidney Diseases
Ex-Officio Members National Institutes of Health
Bethesda, MD
Clarice D. Brown, M.S.
Project Manager James P. Kiley, Ph.D.*
CODA Research, Inc. Director
Silver Spring, MD Airway Biology and Disease Program
Division of Lung Diseases
Karen A. Donato, M.S., R.D.* National Heart, Lung, and Blood Institute
Executive Director of the Panel National Institutes of Health
Coordinator Bethesda, MD
NHLBI Obesity Education Initiative
National Heart, Lung, and Blood Institute Eva Obarzanek, Ph.D., R.D., M.P.H.*
National Institutes of Health Research Nutritionist
Bethesda, MD Prevention Scientific Research Group
Division of Epidemiology and Clinical
Nancy Ernst, Ph.D., R.D.* Applications
Nutrition Coordinator National Heart, Lung, and Blood Institute
Office of the Director National Institutes of Health
Division of Epidemiology and Clinical Applications Bethesda, MD
National Heart, Lung, and Blood Institute
National Institutes of Health
Bethesda, MD Consultant
D. Robin Hill, Ph.D.* David Schriger, M.D., M.P.H., F.A.C.E.P.
Social Science Analyst Associate Professor
Behavioral Medicine Branch UCLA Emergency Medicine Center
Division of Epidemiology and Clinical University of California at Los Angeles
Applications School of Medicine
National Heart, Lung, and Blood Institute Los Angeles, CA
National Institutes of Health
Bethesda, MD
San Antonio Cochrane Center
Michael J. Horan, M.D., Sc.M.*
Director Elaine Chiquette, Pharm.D.
Division of Heart and Vascular Diseases V.A. Cochrane Center at San Antonio
National Heart, Lung, and Blood Institute Audie L. Murphy Memorial Veterans Hospital
National Institutes of Health San Antonio, TX
Bethesda, MD
* NHLBI Obesity Education Initiative Task Force Members
iv

7. Cynthia Mulrow, M.D., M.Sc.
V.A. Cochrane Center at San Antonio
Audie L. Murphy Memorial Veterans Hospital
San Antonio, TX
Staff
Adrienne Blount, B.S.
R.O.W. Sciences, Inc.
Rockville, MD
Maureen Harris, M.S., R.D.
R.O.W. Sciences, Inc.
Rockville, MD
Anna Hodgson, M.A.
R.O.W. Sciences, Inc.
Rockville, MD
Pat Moriarty, M.Ed., R.D.
R.O.W. Sciences, Inc.
Rockville, MD
The panel acknowledges the assistance of Dr.
Rashid Chotani, Johns Hopkins University; Dr.
Robert Klesges, University of Memphis; Dr.
Walter Pories, East Carolina University; Dr. Ivan
Baines, NHLBI; Dr. Christine Kelly, NHLBI;
Glen Bennett, NHLBI; Dr. Fred Heydrick,
BioReview; Debbie Lurie, Prospect Associates;
Estelle Schwalb, Prospect Associates; Lori
McCray, R.O.W. Sciences, Inc.; and
Niyati Pandya, R.O.W. Sciences, Inc.
v

8. Contents
Foreword vii 2. Classification of Overweight and
Executive Summary xi Obesity 58
C. Assessment of Risk Status 62
1. Introduction 1 D. Evaluation and Treatment Strategy 65
A. Rationale for Guidelines Development 1 E. Exclusion from Weight Loss Therapy 70
B. Objectives of the Guidelines 2 F. Patient Motivation 70
C. Guideline Development Methodology 2 G. Goals of Weight Loss and
D. Statement of Assumptions 5 Management 71
E. Intended Users of These Guidelines 5 1. Weight Loss 71
2. Weight Maintenance at
2. Overweight and Obesity: Background 6 Lower Weight 72
A. Health and Economic Costs 6 3. Prevention of Further Weight Gain 73
1. Prevalence and Time Trends 6 H. Strategies for Weight Loss and
2. Demographic Variations in Weight Maintenance 73
Overweight and Obesity Prevalence 9 1. Dietary Therapy 73
3. Economic Costs of Overweight 2. Physical Activity 77
and Obesity 9 3. Behavior Therapy 81
B. Prevention of Overweight and Obesity 11 4. Combined Therapy 83
C. Health Risks of Overweight and Obesity 12 5. Pharmacotherapy 83
1. Morbidity 12 6. Surgery 86
2. Overweight/Obesity and Morbidity I. Smoking Cessation in the Overweight
in Minority Populations 23 or Obese Patient 91
3. Obesity and Mortality 23 J. Role of Health Professionals in
D. Weight Loss and Mortality 25 Weight Loss Therapy 92
E. Environment 26
F. Genetic Influence in the Development 5. Summary of Recommendations 95
of Overweight and Obesity 27
6. Future Research 98
3 Examination of Randomized Controlled A. Intervention Approaches 98
Trial Evidence 29 B. Causes and Mechanisms of
A. Why Treat Overweight and Obesity? 29 Overweight and Obesity 99
1. Blood Pressure 29 C. Abdominal Fat, Body Weight and
2. Serum/Plasma Lipids and Disease Risk 99
Lipoproteins 33 D. Assessment Methods 99
3. Impaired Glucose Tolerance
and Diabetes 39 7. Appendices 100
4. Decreases in Abdominal Fat with Appendix I.A.1 Guidelines Development
Weight Loss 41 Methodology 100
B. What Treatments are Effective? 42 Appendix I.A.2 Literature Review 109
1. Dietary Therapy 42 Appendix II Description of Evidence 112
2. Physical Activity 44 Appendix III Special Populations 117
3. Combined Therapy 47 Appendix IV Obesity and Sleep Apnea 137
4. Behavior Therapy 48 Appendix V Body Mass Index Chart—
5. Pharmacotherapy 53 How to Measure Obesity 139
6. Surgery 54 Appendix VI Practical Dietary Therapy
7. Other Interventions for Overweight Information 141
and Obesity Treatment 55 Appendix VII Resource List 165
Appendix VIII Glossary of Terms 168
4. Treatment Guidelines 56
A. Overview 56 List of Abbreviations 179
B. Assessment and Classification of
Reference List 181
Overweight and Obesity 56
1. Assessment of Overweight and Publication List 226
Obesity 56
vi

9. F OREWORD
In 1995, the National Obesity Education members methodically and critically examined a
Initiative of the National Heart, Lung, and vast amount of published scientific evidence.
Blood Institute (NHLBI), in cooperation with The panel also obtained scientific input from
the National Institute of Diabetes and Digestive approximately 115 outside reviewers. The result
and Kidney Diseases (NIDDK), convened the was The Clinical Guidelines on the Identification,
first Expert Panel on the Identification, Evaluation, and Treatment of Overweight and
Evaluation, and Treatment of Overweight and Obesity in Adults: The Evidence Report. Dr.
Obesity in Adults to develop clinical practice David Schriger of the University of California at
guidelines for primary care practitioners. Los Angeles, who is a methodologist consultant
in the area of evidence-based practice guidelines,
The impetus for these guidelines was the recog-
and Dr. Elaine Chiquette of the San Antonio
nition that the prevalence of overweight and
Cochrane Center in Texas, who developed the
obesity in the United States is increasing, and
evidence tables, served as key advisors to the
that practitioners need to be alerted to the
panel.
accompanying health risks. According to the lat-
est statistics from the third National Health and Evidence examined by the panel included:
Nutrition Examination Survey, 97 million research on the relationship of overweight and
Americans are overweight or obese. Excess obesity to high blood pressure, high blood cho-
weight is often accompanied by high blood pres- lesterol, type 2 diabetes, stroke, congestive heart
sure, high blood cholesterol, type 2 diabetes, failure, coronary heart disease, various cancers,
coronary heart disease, and other health prob- osteoarthritis, and sleep apnea; risks associated
lems. The total costs attributable to obesity-relat- with the distribution and amount of body fat;
ed disease approach $100 billion annually in the and various treatment strategies, including diet,
United States. physical activity, behavior therapy, pharma-
cotherapy, and surgery. The resulting guidelines
The panel used the principles of evidence-based
document how different treatment strategies
medicine, including an evidence model and evi-
affect weight loss and how weight control affects
dence categories. It was the first time a panel
the major risk factors for heart disease and
thoroughly examined the scientific evidence for
stroke.
risks associated with overweight and obesity, and
their treatments, and developed clinical practice The guidelines have been reviewed and endorsed
recommendations based on their conclusions. by many professional organizations. In fact,
because of the associated risks between high
The panel was headed by Dr. F. Xavier Pi-
blood pressure and high blood cholesterol and
Sunyer, of St. Luke’s/Roosevelt Hospital Center
overweight and obesity, the document represents
in New York City. He and the other 23 panel
vii

10. the first clinical practice guidelines to be
reviewed and endorsed by members of the coor-
dinating committees of both the National
Cholesterol Education Program and the
National High Blood Pressure Education
Program which comprise approximately 52 pro-
fessional societies, government agencies, and
consumer organizations. Two additional groups
endorsing the guidelines are the North American
Association for the Study of Obesity and the
NIDDK National Task force on the Prevention
and Treatment of Obesity.
The report, the evidence model and its accom-
panying evidence tables, and a body mass index
calculator are available on the NHLBI website at
the following location: http://www.nhlbi.nih.
gov./nhlbi/cardio/obes/prof/guidelns/ob_home.
htm
An abbreviated version of the evidence report is
being prepared and will be distributed to prima-
ry care physicians, nurses, registered dietitians
and nutritionists, and other health care practi-
tioners.
It is our hope that these clinical guidelines will
not only help the health care practitioner under-
stand the importance of weight management but
also provide them with the tools to assess and
treat their patients more effectively. Equally
important, we hope that the guidelines lead to a
greater public understanding of obesity and a
greater appreciation for the persistent efforts of
millions of people to lose weight.
Claude Lenfant, M.D.
Director
National Heart, Lung,
and Blood Institute
viii

11. EVIDENCE REPORT ENDORSEMENTS
NATIONAL CHOLESTEROL EDUCATION PROGRAM (NCEP)
Coordinating Committee Member Organizations
Theodore G. Ganiats, M.D., American Academy of Family Physicians, Gary Graham, M.D., American Academy of Insurance
Medicine, Ronald Kleinman, M.D., American Academy of Pediatrics, Ann Smith, R.N., C.O.H.N.-S., American Association of
Occupational Health Nurses, Richard C. Pasternak, M.D., F.A.C.C., American College of Cardiology, Gerald T. Gau, M.D., American
College of Chest Physicians, Ruth Ann Jordan, M.D., American College of Occupational and Environmental Medicine, Thomas E.
Nolan, M.D., American College of Obstetricians and Gynecologists, Alan J. Garber, M.D., Ph.D., American Diabetes Association, Inc.,
Linda Van Horn, Ph.D., R.D., American Dietetic Association, Scott Grundy, M.D., Ph.D., American Heart Association, Sandra
Cornett, R.N., Ph.D., American Hospital Association, Yank D. Coble, Jr., M.D., American Medical Association, Joan Watson, R.N.,
Ph.D., F.A.A.N., American Nurses’ Association, Michael Clearfield, D.O., American Osteopathic Association, Joanne Mitten, M.H.E.,
Association of State and Territorial Health Officials, Gerald J. Wilson, M.B.A., Citizens for Public Action on Blood Pressure and
Cholesterol, Inc., Linda Burnes-Bolton, Dr.P.H., R.N., National Black Nurses’ Association, Inc., Luther T. Clark, M.D., National
Medical Association, Darlene Lansing, M.P.H., R.D., Society for Nutrition Education
Associate Member Coordinating Committee Organizations
Stanley Wallach, M.D., American College of Nutrition, Donald O. Fedder, Dr.P.H., M.P.H., Society for Public Health Education
Federal Agency Liaison Coordinating Committee Representatives
Yvonne L. Bronner, Sc.D., R.D., L.D., NHLBI Ad Hoc Committee on Minority Populations, Francis D. Chesley, M.D., Agency for
Health Care Policy and Research, William H. Dietz, M.D., Ph.D., Centers for Disease Control and Prevention, Thomas M. Lasater,
Ph.D., Coordinating Committee for the Community Demonstration Studies, Alanna Moshfegh, M.S., R.D., Department of Agriculture,
Col. Michael Parkinson, M.D., M.P.H., Department of Defense, Pamela Steele, M.D., Department of Veterans Affairs, Celia Hayes,
M.P.H., R.D., Health Resources and Services Administration, Clifford Johnson, M.P.H., National Center for Health Statistics, Linda
Meyers, Ph.D., Office of Disease Prevention and Health Promotion
NATIONAL HIGH BLOOD PRESSURE EDUCATION PROGRAM (NHBPEP)
Coordinating Committee Member Organizations
Lee A. Green, M.D., M.P.H., American Academy of Family Physicians, Jack P. Whisnant, M.D., American Academy of Neurology,
Barry N. Hyman, M.D., F.A.C.P., American Academy of Ophthalmology, Lisa Mustone-Alexander, M.P.H., P.A., American Academy
of Physician Assistants, Henry Guevara, B.S.N., R.N., C.O.H.N.-S., American Association of Occupational Health Nurses, Edward D.
Frohlich, M.D., American College of Cardiology, Sheldon G. Sheps, M.D., American College of Chest Physicians, Ron Stout, M.D.,
American College of Occupational and Environmental Medicine, Jerome D. Cohen, M.D., American College of Physicians, Carlos
Vallbona, M.D., American College of Preventive Medicine, James R. Sowers, M.D., American Diabetes Association, Inc., Mary C.
Winston, Ed.D., R.D., American Dietetic Association, Daniel W. Jones, M.D., American Heart Association, Roxane Spitzer, Ph.D.,
F.A.A.N., American Hospital Association, Nancy Houston Miller, B.S.N., American Nurses’ Association, Linda Casser, O.D., American
Optometric Association, William A. Nickey, D.O., American Osteopathic Association, Raymond W. Roberts, Pharm.D., American
Pharmaceutical Association, Pamela J. Colman, D.P.M., American Podiatric Medical Association, Nancy McKelvey, M.S.N., R.N.,
American Red Cross, Barry L. Carter, Pharm.D., F.C.C.P., American Society of Health-System Pharmacists, Norman M. Kaplan, M.D.,
American Society of Hypertension, Jackson T. Wright, M.D., Ph.D., Association of Black Cardiologists, Gerald J. Wilson, M.B.A.,
Citizens for Public Action on Blood Pressure and Cholesterol, Inc., Joseph L. Izzo, Jr., M.D., Council on Geriatric Cardiology, James W.
Reed, M.D., F.A.C.P., F.A.C.E., International Society on Hypertension in Blacks, Rita Strickland, Ed.D., R.N., National Black Nurses’
Association, Inc., William Manger, M.D., Ph.D., National Hypertension Association, Inc., Murray Epstein, M.D., National Kidney
Foundation, Inc., Otelio S. Randall, M.D., F.A.C.C., National Medical Association, Edwin Marshall, O.D., M.P.H., National
Optometric Association, Harold W. “Pete” Todd, National Stroke Association, Kathryn M. Kolasa, Ph.D., R.D., L.D.N., Society for
Nutrition Education
Federal Agency Liaison Coordinating Committee Representatives
Keith Ferdinand, M.D., F.A.C.C., NHLBI Ad Hoc Committee on Minority Populations, Francis D. Chesley, M.D., Agency for Health
Care Policy and Research, H. Mitchell Perry, Jr., M.D., Department of Veterans Affairs, Jay Merchant, M.H.A., Health Care Financing
Administration, Vicki Burt, R.N., Sc.M., National Center for Health Statistics, Elizabeth H. Singer, M.S., National Institute of
Diabetes and Digestive and Kidney Diseases (NIDDK)
NIDDK NATIONAL TASK FORCE ON THE PREVENTION AND TREATMENT OF OBESITY
NORTH AMERICAN ASSOCIATION FOR THE STUDY OF OBESITY (NAASO)
ix

13. E XECUTIVE S UMMARY
Introduction tural, physiological, metabolic and genetic factors.
An estimated 97 million adults in the United
While there is agreement about the health risks
States are overweight or obese, a condition that
of overweight and obesity, there is less agreement
substantially raises their risk of morbidity from
about their management. Some have argued
hypertension, dyslipidemia, type 2 diabetes,
against treating obesity because of the difficulty
coronary heart disease, stroke, gallbladder dis-
in maintaining long-term weight loss and of
ease, osteoarthritis, sleep apnea and respiratory
potentially negative consequences of the fre-
problems, and endometrial, breast, prostate, and
quently seen pattern of weight cycling in obese
colon cancers. Higher body weights are also asso-
subjects. Others argue that the potential hazards
ciated with increases in all-cause mortality. Obese
of treatment do not outweigh the known hazards
individuals may also suffer from social stigmati-
of being obese. The intent of these guidelines is
zation and discrimination. As a major contributor
to provide evidence for the effects of treatment
to preventive death in the United States today,
on overweight and obesity. The guidelines focus
overweight and obesity pose a major public
on the role of the primary care practitioner in
health challenge.
treating overweight and obesity.
Overweight is here defined as a body mass index
Evidence-Based Guidelines
(BMI) of 25 to 29.9 kg/m2 and obesity as a BMI
To evaluate published information and to deter-
of ≥ 30 kg/m2. However, overweight and obesity
mine the most appropriate treatment strategies
are not mutually exclusive, since obese persons
that would constitute evidence-based clinical
are also overweight. A BMI of 30 is about 30 lb
guidelines on overweight and obesity for physi-
overweight and equivalent to 221 lb in a 6'0"
cians and associated health professionals in clini-
person and to 186 lb in one 5'6". The number
cal practice, health care policy makers, and clini-
of overweight and obese men and women has
cal investigators, the National Heart, Lung, and
risen since 1960; in the last decade the percent-
Blood Institute’s Obesity Education Initiative in
age of people in these categories has increased to
cooperation with the National Institute of
54.9 percent of adults age 20 years or older.
Diabetes and Digestive and Kidney Diseases con-
Overweight and obesity are especially evident in
vened the Expert Panel on the Identification,
some minority groups, as well as in those with
Evaluation, and Treatment of Overweight and
lower incomes and less education.
Obesity in Adults in May 1995. The guidelines
Obesity is a complex multifactorial chronic dis- are based on a systematic review of the published
ease that develops from an interaction of geno- scientific literature found in MEDLINE from
type and the environment. Our understanding of January 1980 to September 1997 of topics iden-
how and why obesity develops is incomplete, but tified by the panel as key to extrapolating the
involves the integration of social, behavioral, cul- data related to the obesity evidence model.
xi

14. Evidence from approximately 394 randomized summarizes the categories of evidence by their
controlled trials (RCTs) was considered by the source and provides a definition for each category.
panel.
s Who is at Risk? All overweight and obese
The panel is comprised of 24 members, 8 ex- adults (age 18 years of age or older) with a
officio members, and a methodologist consul- BMI of ≥25 are considered at risk for devel-
tant. Areas of expertise contributed to by panel oping associated morbidities or diseases such
members included primary care, epidemiology, as hypertension, high blood cholesteral, type
clinical nutrition, exercise physiology, psycholo- 2 diabetes, coronary heart disease, and other
gy, physiology, and pulmonary disease. There diseases. Individuals with a BMI of 25 to
were five meetings of the full panel and two 29.9 are considered overweight, while individ-
additional meetings of the executive committee uals with a BMI ≥30 are considered obese.
comprised of the panel chair and four panel Treatment of overweight is recommended
members. only when patients have two or more risk fac-
The San Antonio Cochrane Center assisted the tors or a high waist circumference. It should
panel in the literature abstraction and in orga- focus on altering dietary and physical activity
nizing the data into appropriate evidence tables. patterns to prevent development of obesity
The center pretested and used a standardized and to produce moderate weight loss.
25-page form or “Critical Review Status Sheet” Treatment of obesity should focus on produc-
for the literature abstraction. Ultimately, 236 ing substantial weight loss over a prolonged
RCT articles were abstracted and the data were period. The presence of comorbidities in over-
then compiled into individual evidence tables weight and obese patients should be consid-
developed for each RCT. The data from these ered when deciding on treatment options.
RCTs served as the basis for many of the recom- s Why Treat Overweight and Obesity? Obesity is
mendations contained in the guidelines. clearly associated with increased morbidity
The panel determined the criteria for deciding and mortality. There is strong evidence that
on the appropriateness of an article. At a mini- weight loss in overweight and obese individu-
mum, studies had to have a time frame from als reduces risk factors for diabetes and car-
start to finish of at least 4 months. The only diovascular disease (CVD). Strong evidence
exceptions were a few 3-month studies related to exists that weight loss reduces blood pressure
dietary therapy and pharmacotherapy. To con- in both overweight hypertensive and nonhy-
sider the question of long-term maintenance, pertensive individuals; reduces serum triglyc-
studies with outcome data provided at approxi- erides and increases high-density lipoprotein
mately 1 year or longer were examined. (HDL)-cholesterol; and generally produces
Excluded were studies in which self-reported some reduction in total serum cholesterol and
weights by subjects were the only indicators used low-density lipoprotein (LDL)-cholesterol.
to measure weight loss. No exclusions of studies Weight loss reduces blood glucose levels in
were made by study size. The panel weighed the overweight and obese persons without dia-
evidence based on a thorough examination of betes; and weight loss also reduces blood glu-
the threshold or magnitude of the treatment cose levels and HbA1c in some patients with
effect. Each evidence statement (other than type 2 diabetes. Although there have been no
those with no available evidence) and each rec- prospective trials to show changes in mortality
ommendation is categorized by a level of evi- with weight loss in obese patients, reductions
dence which ranges from A to D. Table ES-1 in risk factors would suggest that develop-
xii

15. Table ES-1:
E V I D E N C E C AT E G O R I E S
Evidence Sources of
Category Evidence Definition
A Randomized Evidence is from endpoints of well-designed RCTs (or trials
controlled trials that depart only minimally from randomization) that provide
(rich body of a consistent pattern of findings in the population for which
data) the recommendation is made. Category A therefore requires
substantial numbers of studies involving substantial numbers
of participants.
B Randomized Evidence is from endpoints of intervention studies that
controlled trials include only a limited number of RCTs, post hoc or subgroup
(limited body analysis of RCTs, or meta-analysis of RCTs. In general,
of data) Category B pertains when few randomized trials exist, they are
small in size, and the trial results are somewhat inconsistent, or
the trials were undertaken in a population that differs from the
target population of the recommendation.
C Nonrandomized Evidence is from outcomes of uncontrolled or nonrandomized
trials trials or from observational studies.
Observational
studies
D Panel Expert judgment is based on the panel’s synthesis of evidence
Consensus from experimental research described in the literature and/or
Judgment derived from the consensus of panel members based on clinical
experience or knowledge that does not meet the above-listed
criteria. This category is used only in cases where the provision
of some guidance was deemed valuable but an adequately
compelling clinical literature addressing the subject of the rec-
ommendation was deemed insufficient to justify placement in
one of the other categories (A through C).
xiii

16. ment of type 2 diabetes and CVD would be s Body Mass Index. The BMI, which describes
reduced with weight loss. relative weight for height, is significantly cor-
related with total body fat content. The BMI
s What Treatments Are Effective? A variety of
should be used to assess overweight and obesi-
effective options exist for the management of
ty and to monitor changes in body weight. In
overweight and obese patients, including
addition, measurements of body weight alone
dietary therapy approaches such as low-calorie
can be used to determine efficacy of weight
diets and lower-fat diets; altering physical
loss therapy. BMI is calculated as weight
activity patterns; behavior therapy techniques;
(kg)/height squared (m2). To estimate BMI
pharmacotherapy*; surgery; and combinations
of these techniques. using pounds and inches, use: [weight
(pounds)/height (inches)2] x 703. Weight clas-
Clinical Guidelines sifications by BMI, selected for use in this
Treatment of the overweight or obese patient is a report, are shown in Table ES-2. A conversion
two-step process: assessment and treatment man- table of heights and weights resulting in
agement. Assessment requires determination of selected BMI units is provided in Table ES-3.
the degree of overweight and overall risk status.
s Waist Circumference. The presence of excess
Management includes both reducing excess body
fat in the abdomen out of proportion to total
weight and instituting other measures to control
body fat is an independent predictor of risk
accompanying risk factors.
factors and morbidity. Waist circumference is
Assessment: When assessing a patient for risk positively correlated with abdominal fat con-
status and as a candidate for weight loss therapy, tent. It provides a clinically acceptable mea-
consider the patient’s BMI, waist circumference, surement for assessing a patient's abdominal
and overall risk status. Consideration also needs fat content before and during weight loss
to be given to the patient’s motivation to lose treatment. The sex-specific cutoffs noted on
weight. the next page can be used to identify
TABLE ES-2:
C L A S S I F I C AT I O N OF OVERWEIGHT AND OBESITY BY BMI
Obesity Class BMI (kg/m2)
Underweight < 18.5
Normal 18.5 – 24.9
Overweight 25.0 – 29.9
Obesity I 30.0 – 34.9
II 35.0 – 39.9
Extreme Obesity III ≥ 40
* As of September 1997, the Food and Drug Administration (FDA) requested the voluntary withdrawal from the market of dexfenfluramine and fenfluramine due
to a reported association between valvular heart disease and the use of dexfenfluramine or fenfluramine alone or combined with phentermine. The use of these
drugs for weight reduction, therefore, is not recommended in this report. Sibutramine is approved by FDA for long-term use. It has limited but definite effects on
weight loss and can facilitate weight loss maintenance (Note: FDA approval for orlistat is pending a resolution of labeling issues and results of Phase III trials.)
xiv

17. HIGH RISK mg/dL), low HDL-cholesterol (< 35 mg/dL),
impaired fasting glucose (fasting plasma glu-
cose of 110 to 125 mg/dL), family history of
Men > 102 cm ( > 40 in)
premature CHD (definite myocardial infarc-
Women > 88 cm ( > 35 in) tion or sudden death at or before 55 years of
age in father or other male first-degree rela-
tive, or at or before 65 years of age in mother
or other female first-degree relative), and age
increased relative risk for the development of (men ≥ 45 years and women ≥ 55 years or
obesity-associated risk factors in most adults postmenopausal). Patients can be classified as
with a BMI of 25 to 34.9 kg/m2: being at high absolute risk if they have three
These waist circumference cutpoints lose their of the aforementioned risk factors. Patients at
incremental predictive power in patients with high absolute risk usually require clinical
a BMI ≥ 35 kg/m2 because these patients will management of risk factors to reduce risk.
exceed the cutpoints noted above. Table ES-4 Patients who are overweight or obese often
adds the disease risk of increased abdominal have other cardiovascular risk factors.
fat to the disease risk of BMI. These cate- Methods for estimating absolute risk status for
gories denote relative risk, not absolute risk; developing cardiovascular disease based on
that is, relative to risk at normal weight. They these risk factors are described in detail in the
should not be equated with absolute risk, National Cholesterol Education Program’s
which is determined by a summation of risk Second Report of the Expert Panel on the
factors. They relate to the need to institute Detection, Evaluation, and Treatment of High
weight loss therapy and do not directly define Blood Cholesterol in Adults (NCEP’s ATP II)
the required intensity of modification of risk and the Sixth Report of the Joint National
factors associated with obesity. Committee on Prevention, Detection,
s Risk Status. Assessment of a patient’s absolute Evaluation, and Treatment of High Blood
risk status requires examination for the pres- Pressure (JNC VI). The intensity of interven-
ence of: tion for cholesterol disorders or hypertension
is adjusted according to the absolute risk sta-
Disease conditions: established coronary heart
tus estimated from multiple risk correlates.
disease (CHD), other atherosclerotic diseases,
These include both the risk factors listed
type 2 diabetes, and sleep apnea; patients with
above and evidence of end-organ damage pre-
these conditions are classified as being at very
sent in hypertensive patients. Approaches to
high risk for disease complications and mor-
therapy for cholesterol disorders and hyper-
tality.
tension are described in ATP II and JNC VI,
Other obesity-associated diseases: gynecologi- respectively. In overweight patients, control of
cal abnormalities, osteoarthritis, gallstones cardiovascular risk factors deserves equal
and their complications, and stress inconti- emphasis as weight reduction therapy.
nence. Reduction of risk factors will reduce the risk
Cardiovascular risk factors: cigarette smoking, for cardiovascular disease whether or not
hypertension (systolic blood pressure ≥ 140 efforts at weight loss are successful.
mm Hg or diastolic blood pressure ≥ 90 mm Other risk factors: physical inactivity and
Hg, or the patient is taking antihypertensive high serum triglycerides (> 200 mg/dL).
agents), high-risk LDL-cholesterol (≥ 160 When these factors are present, patients can
xv

18. Table ES-3:
S E L E C T E D BMI U N I T S C AT E G O R I Z E D BY INCHES (CM) AND POUNDS (KG)
Body weight in pounds (kg)
Height in inches (cm) BMI 25 kg/m 2
BMI 27 kg/m2 BMI 30 kg/m2
58 (147.32) 119 (53.98) 129 (58.51) 143 (64.86)
59 (149.86) 124 (56.25) 133 (60.33) 148 (67.13)
60 (152.40) 128 (58.06) 138 (62.60) 153 (69.40)
61 (154.94) 132 (59.87) 143 (64.86) 158 (71.67)
62 (157.48) 136 (61.69) 147 (66.68) 164 (74.39)
63(160.02) 141 (63.96) 152 (68.95) 169 (76.66)
64 (162.56) 145 (65.77) 157 (71.21) 174 (78.93)
65 (165.10) 150 (68.04) 162 (73.48) 180 (81.65)
66 (167.64) 155 (70.31) 167 (75.75) 186 (84.37)
67 (170.18) 159 (72.12) 172 (78.02) 191 (86.64)
68 (172.72) 164 (74.39) 177 (80.29) 197 (89.36)
69 (175.26) 169 (76.66) 182 (82.56) 203 (92.08)
70 (177.80) 174 (78.93) 188 (85.28) 207 (93.89)
71 (180.34) 179 (81.19) 193 (87.54) 215 (97.52)
72 (182.88) 184 (83.46) 199 (90.27) 221 (100.25)
73 (185.42) 189 (85.73) 204 (92.53) 227 (102.97)
74 (187.96) 194 (88.00) 210 (95.26) 233 (105.69)
75 (190.50) 200 (90.72) 216 (97.98) 240 (108.86)
76 (193.04) 205 (92.99) 221(100.25) 246 (111.58)
Metric conversion formula = Non-metric conversion formula =
weight (kg)/height (m) 2
[weight (pounds)/height (inches)2] x 703
Example of BMI calculation: Example of BMI calculation:
A person who weighs 78.93 kilograms and is A person who weighs 164 pounds and is
177 centimeters tall has a BMI of 25: 68 inches (or 5' 8") tall has a BMI of 25:
weight (78.93 kg)/height (1.77 m)2 = 25 [weight(164 pounds)/height (68 inches)2] x
703 = 25
xvi

19. be considered to have incremental absolute patient’s motivation for weight loss and pre-
risk above that estimated from the preceding pare the patient for treatment. This can be
risk factors. Quantitative risk contribution is done by enumerating the dangers accompany-
not available for these risk factors, but their ing persistent obesity and by describing the
presence heightens the need for weight reduc- strategy for clinically assisted weight reduc-
tion in obese persons. tion. Reviewing the patients’ past attempts at
weight loss and explaining how the new treat-
s Patient Motivation. When assessing the
ment plan will be different can encourage
patient’s motivation to enter weight loss ther-
patients and provide hope for successful
apy, the following factors should be evaluated:
weight loss.
reasons and motivation for weight reduction;
previous history of successful and unsuccess- Evaluation and Treatment: The general goals of
ful weight loss attempts; family, friends, and weight loss and management are: (1) at a mini-
work-site support; the patient’s understanding mum, to prevent further weight gain; (2) to
of the causes of obesity and how obesity con- reduce body weight; and (3) to maintain a lower
tributes to several diseases; attitude toward body weight over the long term. The overall
physical activity; capacity to engage in physi- strategy for the evaluation and treatment of
cal activity; time availability for weight loss overweight and obese patients is presented in the
intervention; and financial considerations. In Treatment Algorithm on the next page. This
addition to considering these issues, the algorithm applies only to the assessment for
health care practitioner needs to heighten a overweight and obesity and subsequent decisions
Table ES-4:
C L A S S I F I C AT I O N OF OVERWEIGHT AND OBESITY BY B M I , WA I S T
CIRCUMFERENCE A N D A S S O C I AT E D D I S E A S E R I S K *
Disease Risk* Relative to Normal Weight
and Waist Circumference
Obesity Men ≤ 102 cm (≤ 40 in) > 102 cm (> 40 in)
BMI (kg/m2) Class Women ≤ 88 cm (≤ 35 in) > 88 cm (> 35 in)
Underweight <18.5 — —
Normal+ 18.5 –24.9 — —
Overweight 25.0 – 29.9 Increased High
Obesity 30.0 – 34.9 I High Very High
35.0 – 39.9 II Very High Very High
Extreme Obesity ≥40 III Extremely High Extremely High
* Disease risk for type 2 diabetes, hypertension, and CVD.
+ Increased waist circumference can also be a marker for increased risk even in persons of normal weight.
xvii

20. xviii
Treatment Algorithm*
1
Patient Encounter
2
Hx of ≥ 25 BMI?
No
Yes
3 BMI
measured in past
2 years?
4 6
BMI ≥ 30 OR
• Measure weight, 5 BMI ≥ 25 OR 7 {[BMI 25 to 29.9
height, and waist waist circumference Yes Assess risk factors Yes
OR waist circumference > 88
circumference > 88 cm (F) cm (F) > 102 cm (M)] 8
• Calculate BMI > 102 cm (M) AND ≥ 2 risk Clinician and patient
factors} devise goals and
No No treatment strategy for
weight loss and risk
factor control
14 12 Does
Yes patient want to Yes
Hx BMI ≥ 25?
lose weight?
9 Progress
Yes
No No being made/goal
15 13 achieved?
Brief reinforcement/ Advise to maintain
educate on weight weight/address No
management other risk factors
16 11 10
Periodic Weight Maintenance counseling: Assess reasons for
Check • Dietary therapy failure to lose weight
Examination • Behavior therapy
• Physical activity
Treatment
* This algorithm applies only to the assessment for overweight and obesity and subsequent decisions based on that assessment. It does not include any initial overall assessment for
cardiovascular risk factors or diseases that are indicated.

21. based on that assessment. It does not include s Strategies for Weight Loss and Weight
any initial overall assessment for cardiovascular Maintenance.
risk factors or diseases that are indicated.
Dietary Therapy: A diet that is individually
s Goals of Weight Loss and Management. planned and takes into account the patient’s
overweight status in order to help create a
The initial goal of weight loss therapy is to
deficit of 500 to 1,000 kcal/day should be an
reduce body weight by approximately 10 per-
integral part of any weight loss program. A
cent from baseline. If this goal is achieved,
patient may choose a diet of 1,000 to 1,200
further weight loss can be attempted, if indi-
kcal/day for women and 1,200 to 1,500
cated through further evaluation.
kcal/day for men. Depending on the patient’s
A reasonable time line for a 10 percent reduc- risk status, the low-calorie diet (LCD) recom-
tion in body weight is 6 months of therapy. mended should be consistent with the
For overweight patients with BMIs in the typ- NCEP’s Step I or Step II Diet (see page 74 of
ical range of 27 to 35, a decrease of 300 to the guidelines). Besides decreasing saturated
500 kcal/day will result in weight losses of fat, total fats should be 30 percent or less of
about 1⁄2 to 1 lb/week and a 10 percent loss in total calories. Reducing the percentage of
6 months. For more severely obese patients dietary fat alone will not produce weight loss
with BMIs > 35, deficits of up to 500 to unless total calories are also reduced.
1,000 kcal/day will lead to weight losses of Isocaloric replacement of fat with carbohy-
about 1 to 2 lb/week and a 10 percent weight drates will reduce the percentage of calories
loss in 6 months. Weight loss at the rate of 1 from fat but will not cause weight loss.
to 2 lb/week (calorie deficit of 500 to 1,000 Reducing dietary fat, along with reducing
kcal/day) commonly occurs for up to 6 dietary carbohydrates, usually will be needed
months. After 6 months, the rate of weight to produce the caloric deficit needed for an
loss usually declines and weight plateaus acceptable weight loss. When fat intake is
because of a lesser energy expenditure at the reduced, priority should be given to reducing
lower weight. saturated fat to enhance lowering of LDL-
Experience reveals that lost weight usually will cholesterol levels. Frequent contacts with the
be regained unless a weight maintenance pro- practitioner during dietary therapy help to
gram consisting of dietary therapy, physical promote weight loss and weight maintenance
activity, and behavior therapy is continued at a lower weight.
indefinitely. Physical Activity: An increase in physical
After 6 months of weight loss treatment, activity is an important component of weight
efforts to maintain weight loss should be put loss therapy, although it will not lead to sub-
in place. If more weight loss is needed, anoth- stantially greater weight loss over 6 months.
er attempt at weight reduction can be made. Most weight loss occurs because of decreased
This will require further adjustment of the caloric intake. Sustained physical activity is
diet and physical activity prescriptions. most helpful in the prevention of weight
regain. In addition, it has a benefit in reduc-
For patients unable to achieve significant ing cardiovascular and diabetes risks beyond
weight reduction, prevention of further that produced by weight reduction alone. For
weight gain is an important goal; such most obese patients, exercise should be initiat-
patients may also need to participate in a ed slowly, and the intensity should be
weight management program.
xix

22. increased gradually. The exercise can be done sidering pharmacotherapy.
all at one time or intermittently over the day.
Pharmacotherapy: In carefully selected
Initial activities may be walking or swimming
patients, appropriate drugs can augment
at a slow pace. The patient can start by walk-
LCDs, physical activity, and behavior therapy
ing 30 minutes for 3 days a week and can
in weight loss. Weight loss drugs that have
build to 45 minutes of more intense walking
been approved by the FDA for long-term use
at least 5 days a week. With this regimen, an
can be useful adjuncts to dietary therapy and
additional expenditure of 100 to 200 calories
physical activity for some patients with a BMI
per day can be achieved. All adults should set
of ≥ 30 with no concomitant risk factors or
a long-term goal to accumulate at least 30
diseases, and for patients with a BMI of ≥ 27
minutes or more of moderate-intensity physi-
with concomitant risk factors or diseases. The
cal activity on most, and preferably all, days
risk factors and diseases considered important
of the week. This regimen can be adapted to
enough to warrant pharmacotherapy at a
other forms of physical activity, but walking is
BMI of 27 to 29.9 are hypertension, dyslipi-
particularly attractive because of its safety and
demia, CHD, type 2 diabetes, and sleep
accessibility. Patients should be encouraged to
apnea. Continual assessment by the physician
increase “every day” activities such as taking
of drug therapy for efficacy and safety is nec-
the stairs instead of the elevator. With time,
essary.
depending on progress and functional capaci-
ty, the patient may engage in more strenuous At the present time, sibutramine is available
activities. Competitive sports, such as tennis for long-term use. (Note: FDA approval of
and volleyball, can provide an enjoyable form orlistat is pending a resolution of labeling
of exercise for many, but care must be taken issues and results of Phase III trials.) It
to avoid injury. Reducing sedentary time is enhances weight loss modestly and can help
another strategy to increase activity by under- facilitate weight loss maintenance. Potential
taking frequent, less strenuous activities. side effects with drugs, nonetheless, must be
kept in mind. With sibutramine, increases in
Behavior Therapy: Strategies, based on learn- blood pressure and heart rate may occur.
ing principles such as reinforcement, that pro- Sibutramine should not be used in patients
vide tools for overcoming barriers to compli- with a history of hypertension, CHD, conges-
ance with dietary therapy and/or increased tive heart failure, arrhythmias, or history of
physical activity are helpful in achieving stroke. With orlistat, fat soluble vitamins may
weight loss and weight maintenance. Specific require replacement because of partial malab-
strategies include self-monitoring of both eat- sorption. All patients should be carefully
ing habits and physical activity, stress manage- monitored for these side effects.
ment, stimulus control, problem solving, con-
tingency management, cognitive restructur- Weight Loss Surgery: Weight loss surgery is
ing, and social support. one option for weight reduction in a limited
number of patients with clinically severe obe-
Combined Therapy: A combined intervention sity, i.e., BMIs ≥ 40 or ≥ 35 with comorbid
of behavior therapy, an LCD, and increased conditions. Weight loss surgery should be
physical activity provides the most successful reserved for patients in whom efforts at med-
therapy for weight loss and weight mainte- ical therapy have failed and who are suffering
nance. This type of intervention should be from the complications of extreme obesity.
maintained for at least 6 months before con-
xx

23. Gastrointestinal surgery (gastric restriction In the obese patient who smokes, smoking
[vertical gastric banding] or gastric bypass cessation is a major goal of risk factor man-
[Roux-en Y]) is an intervention weight loss agement. Many well-documented health ben-
option for motivated subjects with acceptable efits accompany smoking cessation, but a
operative risks. An integrated program must major obstacle to cessation has been the
be in place to provide guidance on diet, phys- attendant weight gain observed in about 80
ical activity, and behavioral and social support percent of quitters. This weight gain averages
both prior to and after the surgery. 4.5 to 7 lb, but in 13 percent of women and
10 percent of men, weight gain exceeds 28 lb.
s Adapt Weight Loss Programs To Meet the
Weight gain that accompanies smoking cessa-
Needs of Diverse Patients. Standard treat-
tion has been quite resistant to most dietary,
ment approaches for overweight and obesity
behavioral, or physical activity interventions.
must be tailored to the needs of various
patients or patient groups. Large individual The weight gained with smoking cessation is
variation exists within any social or cultural less likely to produce negative health conse-
group; furthermore, substantial overlap quences than would continued smoking. For
among subcultures occurs within the larger this reason, smoking cessation should be
society. There is, therefore, no “cookbook” or strongly advocated regardless of baseline
standardized set of rules to optimize weight weight. Prevention of weight gain through
reduction with a given type of patient. diet and physical activity should be stressed.
However, to be more culturally sensitive and For practical reasons, it may be prudent to
to incorporate patient characteristics in obesi- avoid initiating smoking cessation and weight
ty treatment programs: consider and adapt loss therapy simultaneously. If weight gain
the setting and staffing for the program; con- ensues after smoking cessation, it should be
sider how the obesity treatment program inte- managed vigorously according to the guide-
grates into other aspects of patient health care lines outlined in this report. Although short-
and self care; and expect and allow for pro- term weight gain is a common side effect of
gram modifications based on patient respons- smoking cessation, this gain does not rule out
es and preferences. the possibility of long-term weight control.
The issues of weight reduction after age 65 SUMMARY OF EVIDENCE-BASED RECOMMENDATIONS
involve such questions as: does weight loss
A A DVANTAGES OF W EIGHT L OSS
reduce risk factors in older adults; are there
risks associated with obesity treatment that The recommendation to treat overweight and
are unique to older adults; and does weight obesity is based not only on evidence that relates
reduction prolong the lives of older adults? obesity to increased mortality but also on RCT
Although there is less certainty about the evidence that weight loss reduces risk factors for
importance of treating overweight at older disease. Thus, weight loss may not only help
ages than at younger ages, a clinical decision control diseases worsened by obesity, it may also
to forgo obesity treatment in older adults help decrease the likelihood of developing these
should be guided by an evaluation of the diseases. The panel reviewed RCT evidence to
potential benefit of weight reduction and the determine the effect of weight loss on blood
reduction of risk for future cardiovascular pressure and hypertension, serum/plasma lipid
events. concentrations, and fasting blood glucose and
fasting insulin. Recommendations focusing on
xxi

24. these conditions underscore the advantages of inclusion in these guidelines, 14 RCT articles
weight loss. examined lifestyle trials while the remaining 8
articles reviewed pharmacotherapy trials. There
1. Blood Pressure
is strong evidence from the 14 lifestyle trials that
To evaluate the effect of weight loss on blood
weight loss produced by lifestyle modifications
pressure and hypertension, 76 articles reporting
in overweight individuals is accompanied by
RCTs were considered for inclusion in these
reductions in serum triglycerides and by increas-
guidelines. Of the 45 accepted articles, 35 were
es in HDL-cholesterol. Weight loss generally
lifestyle trials and 10 were pharmacotherapy tri-
produces some reductions in serum total choles-
als. There is strong and consistent evidence from
terol and LDL-cholesterol. Limited evidence
these lifestyle trials in both overweight hyperten-
exists that a decrease in abdominal fat correlates
sive and nonhypertensive patients that weight
with improvements in lipids, although the effect
loss produced by lifestyle modifications reduces
may not be independent of weight loss, and
blood pressure levels. Limited evidence exists
there is strong evidence that increased aerobic
that decreases in abdominal fat will reduce blood
activity to increase cardiorespiratory fitness
pressure in overweight nonhypertensive individ-
favorably affects blood lipids, particularly if
uals, although not independent of weight loss,
accompanied by weight loss. There is suggestive
and there is considerable evidence that increased
evidence from the eight randomized pharma-
aerobic activity to increase cardiorespiratory fit-
cotherapy trials that weight loss produced by
ness reduces blood pressure (independent of
weight loss medications and adjuvant lifestyle
weight loss). There is also suggestive evidence
modifications, including caloric restriction and
from randomized trials that weight loss pro-
physical activity, does not result in consistent
duced by most weight loss medications, except
effects on blood lipids. The following recom-
for sibutramine, in combination with adjuvant
mendation is based on the review of the data in
lifestyle modifications will be accompanied by
these 22 RCT articles:
reductions in blood pressure. Based on a review
of the evidence from the 45 RCT blood pressure
articles, the panel makes the following recom- Weight loss is recommended to lower ele-
mendation: vated levels of total cholesterol, LDL-cho-
lesterol, and triglycerides, and to raise low
levels of HDL-cholesterol in overweight
Weight loss is recommended to lower ele-
and obese persons with dyslipidemia.
vated blood pressure in overweight and
Evidence Category A.
obese persons with high blood pressure.
Evidence Category A.
3. Blood Glucose
To evaluate the effect of weight loss on fasting
2. Serum/Plasma Lipids
blood glucose and fasting insulin levels, 49 RCT
Sixty-five RCT articles were evaluated for the
articles were reviewed for inclusion in these
effect of weight loss on serum/plasma concentra-
guidelines. Of the 17 RCT articles accepted, 9
tions of total cholesterol, LDL-cholesterol, very
RCT articles examined lifestyle therapy trials
low-density lipoprotein (VLDL)-cholesterol,
and 8 RCT articles considered the effects of
triglycerides, and HDL-cholesterol. Studies were
pharmacotherapy on weight loss and subsequent
conducted on individuals over a range of obesity
changes in blood glucose. There is strong evi-
and lipid levels. Of the 22 articles accepted for
dence from the nine lifestyle therapy trials that
xxii

25. weight loss produced by lifestyle modification on nonrandomized studies as well as clinical
reduces blood glucose levels in overweight and experience.
obese persons without diabetes, and weight loss
1. BMI To Assess Overweight and Obesity
reduces blood glucose levels and HbA lc in some
There are a number of accurate methods to
patients with type 2 diabetes. There is suggestive
assess body fat (e.g., total body water, total body
evidence that decreases in abdominal fat will
potassium, bioelectrical impedance, and dual-
improve glucose tolerance in overweight individ-
energy X-ray absorptiometry), but no trial data
uals with impaired glucose tolerance, although
exist to indicate that one measure of fatness is
not independent of weight loss; and there is lim-
better than any other for following overweight
ited evidence that increased cardiorespiratory fit-
and obese patients during treatment. Since mea-
ness improves glucose tolerance in overweight
suring body fat by these techniques is often
individuals with impaired glucose tolerance or
expensive and is not readily available, a more
diabetes, although not independent of weight
practical approach for the clinical setting is the
loss. In addition, there is suggestive evidence
measurement of BMI; epidemiological and
from randomized trials that weight loss induced
observational studies have shown that BMI pro-
by weight loss medications does not appear to
vides an acceptable approximation of total body
improve blood glucose levels any better than
fat for the majority of patients. Because there are
weight loss through lifestyle therapy in over-
no published studies that compare the effective-
weight persons both with and without type 2
ness of different measures for evaluating changes
diabetes. Based on a full review of the data in
in body fat during weight reduction, the panel
these 17 RCT articles, the panel makes the fol-
bases its recommendation on expert judgment
lowing recommendation:
from clinical experience:
Weight loss is recommended to lower ele-
Practitioners should use the BMI to assess
vated blood glucose levels in overweight
overweight and obesity. Body weight alone
and obese persons with type 2 diabetes.
can be used to follow weight loss, and to
Evidence Category A.
determine efficacy of therapy. Evidence
Category C.
B M EASUREMENT OF D EGREE OF
2. BMI To Estimate Relative Risk
O VERWEIGHT AND O BESITY
In epidemiological studies, BMI is the favored
Patients should have their BMI and levels of measure of excess weight to estimate relative risk
abdominal fat measured not only for the initial of disease. BMI correlates both with morbidity
assessment of the degree of overweight and obe- and mortality; the relative risk for CVD risk fac-
sity, but also as a guide to the efficacy of weight tors and CVD incidence increases in a graded
loss treatment. Although there are no RCTs that fashion with increasing BMI in all population
review measurements of overweight and obesity, groups. Moreover, calculating BMI is simple,
the panel determined that this aspect of patient rapid, and inexpensive, and can be applied gen-
care warranted further consideration and that erally to adults. The panel, therefore, makes this
this guidance was deemed valuable. Therefore, recommendation:
the following four recommendations that are
included in the Treatment Guidelines were based
xxiii

26. patient is very short, or has a BMI above the 25
to 34.9 range, waist cutpoints used for the gen-
The BMI should be used to classify over-
eral population may not be applicable. Based on
weight and obesity and to estimate rela-
the evidence from nonrandomized studies, the
tive risk of disease compared to normal
panel makes this recommendation:
weight. Evidence Category C.
For adult patients with a BMI of 25 to
3. Assessing Abdominal Fat
34.9 kg/m2, sex-specific waist circumference
For the most effective technique for assessing
cutoffs should be used in conjunction with
abdominal fat content, the panel considered
BMI to identify increased disease risks.
measures of waist circumference, waist-to-hip
Evidence Category C.
ratio (WHR), magnetic resonance imaging
(MRI), and computed tomography. Evidence
from epidemiological studies shows waist cir-
cumference to be a better marker of abdominal C G OALS FOR W EIGHT L OSS
fat content than WHR, and that it is the most
The general goals of weight loss and manage-
practical anthropometric measurement for
ment are to reduce body weight, to maintain a
assessing a patient’s abdominal fat content before
lower body weight over the long term, and to
and during weight loss treatment. Computed
prevent further weight gain. Evidence indicates
tomography and MRI are both more accurate
that a moderate weight loss can be maintained
but impractical for routine clinical use. Based on
over time if some form of therapy continues. It
evidence that waist circumference is a better
is better to maintain a moderate weight loss over
marker than WHR—and taking into account
a prolonged period than to regain from a
that the MRI and computed tomography tech-
marked weight loss.
niques are expensive and not readily available for
clinical practice—the panel makes the following 1. Initial Goal of Weight Loss from Baseline
recommendation: There is strong and consistent evidence from
randomized trials that overweight and obese
patients in well-designed programs can achieve a
The waist circumference should be used to weight loss of as much as 10 percent of baseline
assess abdominal fat content. Evidence weight. In the diet trials, an average of 8 percent
Category C. of baseline weight was lost. Since this average
includes persons who did not lose weight, an
individualized goal of 10 percent is reasonable.
4. Sex-Specific Measurements The panel, therefore, recommends that:
Evidence from epidemiological studies indicates
that a high waist circumference is associated
with an increased risk for type 2 diabetes, dys- The initial goal of weight loss therapy
lipidemia, hypertension, and CVD. Therefore, should be to reduce body weight by approx-
the panel judged that sex-specific cutoffs for imately 10 percent from baseline. With
waist circumference can be used to identify success, further weight loss can be attempt-
increased risk associated with abdominal fat in ed if indicated through further assessment.
adults with a BMI in the range of 25 to 34.9. Evidence Category A.
These cutpoints can be applied to all adult eth-
nic or racial groups. On the other hand, if a
xxiv

27. 2. Amount of Weight Loss weight loss than lower-fat diets alone. Further,
Randomized trials suggest that weight loss at the VLCDs produce greater initial weight losses
rate of 1 to 2 lb/week (calorie deficit of 500 to than LCDs (over the long term of >1 year,
1,000 kcal/day) commonly occurs for up to 6 weight loss is not different than that of the
months. LCDs). In addition, randomized trials suggest
that no improvement in cardiorespiratory fitness
as measured by VO2 max appears to occur in
Weight loss should be about 1 to 2 lb/week obese adults who lose weight on LCDs alone
for a period of 6 months, with the subse- without physical activity. The following recom-
quent strategy based on the amount of mendations are based on the evidence extracted
weight lost. Evidence Category B. from the 48 accepted articles:
LCDs are recommended for weight loss in
D H OW T O A CHIEVE W EIGHT L OSS overweight and obese persons. Evidence
The panel reviewed relevant treatment strategies Category A. Reducing fat as part of an
designed for weight loss that can also be used to LCD is a practical way to reduce calories.
foster long-term weight control and prevention Evidence Category A.
of weight gain. The consequent recommenda-
tions emphasize the potential effectiveness of Reducing dietary fat alone without reduc-
weight control using multiple interventions and ing calories is not sufficient for weight loss.
strategies, including dietary therapy, physical However, reducing dietary fat, along with
activity, behavior therapy, pharmacotherapy, and reducing dietary carbohydrates, can facili-
surgery, as well as combinations of these strate- tate caloric reduction. Evidence Category A.
gies.
1. Dietary Therapy A diet that is individually planned to help
The panel reviewed 86 RCT articles to deter- create a deficit of 500 to 1,000 kcal/day
mine the effectiveness of diets on weight loss should be an intregal part of any program
(including LCDs, very low-calorie diets aimed at achieving a weight loss of 1 to 2
(VLCDs), vegetarian diets, American Heart lb/week. Evidence Category A.
Association dietary guidelines, the NCEP’s Step
I diet with caloric restriction, and other low-fat
regimens with varying combinations of 2. Physical Activity
macronutrients). Of the 86 articles reviewed, 48 Effects of Physical Activity on Weight Loss
were accepted for inclusion in these guidelines. Twenty-three RCT articles were reviewed to
These RCTs indicate strong and consistent evi- determine the effect of physical activity on
dence that an average weight loss of 8 percent of weight loss, abdominal fat (measured by waist
initial body weight can be obtained over 3 to 12 circumference), and changes in cardiorespiratory
months with an LCD and that this weight loss fitness (VO2 max). Thirteen of these articles
effects a decrease in abdominal fat; and, were accepted for inclusion in these guidelines.
although lower-fat diets without targeted caloric A review of these articles reveals strong evidence
reduction help promote weight loss by produc- that physical activity alone, i.e., aerobic exercise,
ing a reduced caloric intake, lower-fat diets with in obese adults results in modest weight loss and
targeted caloric reduction promote greater that physical activity in overweight and obese
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28. adults increases cardiorespiratory fitness, inde- physical activity produces greater weight loss
pendent of weight loss. Randomized trials sug- than diet alone or physical activity alone, and
gest that increased physical activity in over- that the combination of diet and physical activi-
weight and obese adults reduces abdominal fat ty improves cardiorespiratory fitness as measured
only modestly or not at all, and that regular by VO2 max in overweight and obese adults
physical activity independently reduces the risk when compared to diet alone. The combined
for CVD. The panel’s recommendation on phys- effect of a reduced calorie diet and increased-
ical activity is based on the evidence from these physical activity seemingly produced modestly
13 articles: greater reductions in abdominal fat than either
diet alone or physical activity alone, although it
has not been shown to be independent of weight
Physical activity is recommended as part of
loss. The panel’s following recommendations are
a comprehensive weight loss therapy and
based on the evidence from these articles:
weight control program because it: (1)
modestly contributes to weight loss in over-
weight and obese adults (Evidence
The combination of a reduced calorie diet
Category A), (2) may decrease abdominal
and increased physical activity is recom-
fat (Evidence Category B), (3) increases
mended since it produces weight loss that
cardiorespiratory fitness (Evidence Category
may also result in decreases in abdominal
A), and (4) may help with maintenance of
fat and increases in cardiorespiratory fit-
weight loss (Evidence Category C).
ness. Evidence Category A.
Physical activity should be an integral part
of weight loss therapy and weight mainte- 3. Behavior Therapy
nance. Initially, moderate levels of physical Thirty-six RCTs were reviewed to evaluate
activity for 30 to 45 minutes, 3 to 5 days whether behavior therapy provides additional
a week, should be encouraged. All adults benefit beyond other weight loss approaches, as
should set a long-term goal to accumulate well as to compare various behavioral tech-
at least 30 minutes or more of moderate- niques. Of the 36 RCTs reviewed, 22 were
intensity physical activity on most, and accepted. These RCTs strongly indicate that
preferably all, days of the week. Evidence behavioral strategies to reinforce changes in diet
Category B. and physical activity in obese adults produce
weight loss in the range of 10 percent over 4
months to 1 year. In addition, no one behavior
therapy appeared superior to any other in its
Effects of Physical Activity and Diet on Weight
Loss (Combined Therapy)
effect on weight loss; multimodal strategies
Twenty-three RCT articles were reviewed to appear to work best and those interventions with
determine the effects on body weight of a com- the greatest intensity appear to be associated
bination of a reduced-calorie diet with increased with the greatest weight loss. Long-term follow-
physical activity. Fifteen of these articles were up of patients undergoing behavior therapy
accepted for inclusion in the guidelines. These shows a return to baseline weight for the great
articles contain strong evidence that the combi- majority of subjects in the absence of continued
nation of a reduced-calorie diet and increased behavioral intervention. Randomized trials sug-
gest that behavior therapy, when used in combi-
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