ENDORSED 18 SEPTEMBER 2003
Clinical Practice Guidelines for the Management
of Overweight and Obesity in Adults
© Commonwealth of Australia 2003
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Disclaimer
This document is a general guide to appropriate practice, to be followed only subject to the clinician’s
judgement in each individual case.
The guidelines are designed to provide information to assist decision-making and are based on the best
information available at the date of compilation.
It is planned to review this Guideline in 2006. For further information regarding the status of this
document, please refer to the NHMRC web address:
For copies of this document contact:
Phone: 1800 020 103 extension 8654 (toll free number)
Email:
Website: www.obesityguidelines.gov.au
C O N T E N T S
Preface vii

CONTENTS
Clinical Practice Guidelines for the Management of Overweight and Obesity in Adults
iii
CONTENTS
Clinical Practice Guidelines for the Management of Overweight and Obesity in Adults
iv
CONTENTS
Clinical Practice Guidelines for the Management of Overweight and Obesity in Adults
v
5 Treatment: energy intake 65
5.1 Existing evidence of the effectiveness of diet therapy 66
5.2 Recent evidence on dietary therapy 67
5.3 Types of dietary approaches 67
5.4 Summary 80
5.5 Gaps in knowledge 80
6 Treatment: physical activity 91
6.1 Secular changes in obesity and physical activity 92
6.2 Recent ndings on physical activity 94
6.3 Summary 109
6.4 Gaps in knowledge 109
7 Treatment: behavioural therapy 119
7.1 Approaches to behavioural therapy 119
7.2 Behavioural treatment outcomes 121
7.3 Behavioural-drug combination therapy 129
7.4 Other psychological factors 129
7.5 Gaps in knowledge 131
8 Treatment: pharmacotherapy 137
8.1 Who should be treated with pharmacotherapy? 139
8.2 Pharmacotherapy treatment options 139
8.3 Drugs that inhibit nutrient absorption 145

Appendix F Orlistat therapy evidence 238
Appendix G Surgical treatment evidence 246
Appendix H Sources for appendixes 258
PREFACE
Clinical Practice Guidelines for the Management of Overweight and Obesity in Adults
vii
P R E FA C E
In recent decades the number of Australians who are overweight or obese has
continued to increase: in 1999-2000 an estimated 67 per cent of adult males and
52 per cent of adult females were classied as overweight or obese. In 1992-93,
it was estimated that obesity was costing Australia $840 million a year, of which
about 63 per cent was being directly borne by the health care system.
In 1997 the National Health and Medical Research Council’s Expert Panel on
Prevention of Obesity and Overweight prepared Acting on Australia’s Weight: a
strategic plan for the prevention of overweight and obesity. The primary outcomes
of that plan were the goals to ‘prevent further weight gain in adults and eventually
reduce the proportion of the adult population that is overweight or obese; and to
ensure healthy growth of children’.
Undoubtedly, most of the work required to tackle overweight and obesity in
Australia will take the form of population-wide strategies seeking to modify the
‘obesogenic’ modern social environment. However, during the development of Acting
on Australia’s Weight and the subsequent strategy, the need for clinical practice
guidelines for the management of overweight and obesity in Australian adults and
children became apparent. So, in 2000, in collaboration with the Population Health
Division of the Commonwealth Department of Health and Ageing, the NHMRC
initiated the development of the guidelines.
In working on the project, and having determined that separate guidelines were
required for adults and for children and adolescents, the NHMRC researched
practices for managing overweight and obesity and ensured that the practices
identied were multi-faceted—for example, strategies that span physical activity,

This epidemic of overweight and obesity is part of a worldwide trend, and it is
contributing to increasing levels of non-communicable metabolic and mechanically
induced disorders such as diabetes, cardiovascular disease, joint problems,
obstructive sleep apnoea, and some cancers.
While the causes of the problem are diverse, it is the interaction between humans’
varying levels of genetic, cultural and socio-economic predisposition to weight
gain, and an increasingly ‘obesogenic’ modern environment, that is propelling the
epidemic and explains the inter-individual differences in response.
A SS E S S ME N T
As well as the assessment of weight related co-morbidities (such as dislipidaemia,
hypertension and hyperglycaemia), clinical assessment of overweight and obesity
requires two other important aspects: examining energy intake and physical activity
levels to assess how energy imbalance has occurred; and considering the nature
of the environment, personal reasons and other factors to understand why it has
occurred.
Clinicians should take into account a person’s weight history, background, family,
work and social environments, the presence of medical co-morbidities, motivation
and readiness to change, and the costs and benets of weight loss before prescribing
any treatment.
M EA S U R EM E N T
There are no perfect measures of overweight and obesity in the clinical situation.
The most useful absolute indicator of risk and relative change is a combination
of anthropometric measures such as body mass index (BMI) or weight and waist
circumference.
SUMMARY
Clinical Practice Guidelines for the Management of Overweight and Obesity in Adults
ix
SUMMARY
Clinical Practice Guidelines for the Management of Overweight and Obesity in Adults
x

(BMI >30 or BMI >27 with risk factors)
InterventionTarget population
SUMMARY
Clinical Practice Guidelines for the Management of Overweight and Obesity in Adults
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SUMMARY
Clinical Practice Guidelines for the Management of Overweight and Obesity in Adults
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T RE AT ME N T: E N ER GY I N TA K E
The effectiveness of any diet depends on the energy imbalance produced by a
reduction in energy intake in relation to energy expenditure. This can be done in
many ways, but some methods are more effective and have less deleterious effects
than others.
A variety of diets involving a reduction in energy intake lead to short-term weight
loss. The current evidence base indicates that low-fat ad libitum eating plans,
resulting in a daily energy reduction of 2 to 4 megajoules a day, in combination with
increased physical activity, appear to be the most effective for long-term weight loss.
It is possible that the primary mechanism through which low-fat diets exert their
inuence is reduction of energy density. Other forms of low-energy density diets
are being researched and may prove equally effective. However, the evidence
is not currently available.
Low-energy (that is, 4 to 5 megajoules a day) and very low energy (1.7 to 3.3 megajoules
a day) formula diets can lead to signicant weight loss in the short term in motivated
people under strict supervision. In the long term (say, ve years), however, they
result in no greater weight losses than an ad libitum low-fat eating plan.
T RE AT ME N T: E N ER GY E X PE ND I T U RE
It is more difcult to cause an energy imbalance leading to short-term weight loss
through physical activity than it is through dietary restriction. A regular pattern
of physical activity is, however, one of the key factors involved in long-term
maintenance of weight loss.

35 and serious medical co-morbidities, although it is increasingly being used
in patients with BMIs lower than this.
Surgically induced weight loss results in a marked reduction in some of the
co-morbidities associated with obesity (particularly diabetes) and an improvement
in quality of life.
Although it may appear expensive relative to other treatments, obesity surgery
is one of the most cost-effective treatments available.
A LT ER NAT I VE T R EAT M EN TS
At present no herbal or other over-the-counter supplements demonstrate sufcient
evidence of long-term weight loss and lack of signicant side effects.
D EA L I N G W I T H C O - MO RB I D I TI ES
The severity of a co-morbidity will determine the type of treatment, but weight loss
should nevertheless be a primary consideration when dealing with all co-morbidities
related to obesity.
In cases of moderately elevated risk factors (such as raised blood sugars or
cholesterol), attempts should be made to manage weight through lifestyle change
before resorting to more intensive treatments.
S UM M A RY O F T R E AT M E N TS
The following table summarises the effect of weight-loss treatments in overweight or
obese adults.
SUMMARY
Clinical Practice Guidelines for the Management of Overweight and Obesity in Adults
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SUMMARY
Clinical Practice Guidelines for the Management of Overweight and Obesity in Adults
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The effects of weight-loss treatments in overweight or obese adults: a summary
Treatment Weight loss/gain (kg) Weight loss/gain (kg) Ability to prevent regain?
over 1-2 years
a

-5.5 (-3.0 to -7.7) -6.5 (-4.2 to -9.5) over 4-5 years Yes, based on limited
-6.0% evidence
Low-glycaemic index, Not known Not known Not known
high-protein or high-
mono-unsaturated
fatty acid diets
Physical activity -1.8 (-5.8 to +0.7) -1.3 (-3.1 to +1.0) over 2-6 years Yes, if 80 minutes or more
-2.1%
f
of daily activity
Diet plus activity -7.5 (-15.2 to -4.2) -3.1 (-9.9 to 0) over 2-6 years Yes, to some degree
-8.1%
Behaviour -4.7 (-12.9 to -0.2) -2.8 (-9.6 to-0.2) over 3-5 years Yes, to some degree
-5.1%
Pharmacological
Diethylpropion -6.5 (-1.9 to -13.1) Not known Yes, while drug is taken
Phentermine -6.3 (-3.6 to -8.8) Not known Yes, while drug is taken
Sibutramine -5.6 (-7.9 to -3.8) Not known Yes, while drug is taken
6.0%
Sibutramine plus -10.8 (-16.6 to -5.2) Not known Yes, while drug is taken
lifestyle modication 10.7%
Orlistat plus a mildly -8.4 (-13.1 to -6.2)
g
-6.9
h
Yes, while drug is taken
hypocaloric diet -8.6% with a normal energy diet
Surgery
Gastric bypass -46 (-53 to -35) -42 (-62 to -29) over 3-14 years Yes
-36%

The grades of recommendation are less formally determined, being based on
previous guidelines.
B AC K G RO UN D
Overweight and obesity are becoming an increasingly serious problem in Australia,
causing more and more, and graver, ill-health. This is part of a worldwide trend
towards obesity, and it is associated with modernisation and changing lifestyles.

Evidence-based statements Evidence level
Overweight and obesity are present in epidemic proportions throughout III-2
Australia: it is estimated that over 67 per cent of adult males and
52 per cent of adult females were overweight or obese in 1999–2000
Overweight poses a health burden at all ages, being associated with a III-2
number of diseases caused by metabolic complications or the excess
weight itself, or both.
A modest weight loss of 5 to 10 per cent of starting body weight III-2
is sufficient to achieve clinically relevant health benefits.
A SS E S S ME N T
Clinical assessment involves two aspects: examining energy intake and expenditure
to determine how energy imbalance has occurred; and considering the nature of
the environment and personal and other factors to understand why it has occurred.
Factors such as a person’s motivation, co-morbidities, and the costs and benets of
weight loss also need to be considered.
Evidence-based statement Evidence level
Food intake and levels of physical activity can be estimated only III-2
approximately in a clinical setting.
Recommendation: level B
• Although it may be necessary to evaluate food intake and energy expenditure in the
clinical situation, the currently available measures should be interpreted with caution.
EVIDENCE-BASED STATEMENTS AND RECOMMENDATIONS
Clinical Practice Guidelines for the Management of Overweight and Obesity in Adults

• A person’s current medication use should be assessed as a potential
cause of weight gain or failure to lose weight.
EVIDENCE-BASED STATEMENTS AND RECOMMENDATIONS
Clinical Practice Guidelines for the Management of Overweight and Obesity in Adults
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EVIDENCE-BASED STATEMENTS AND RECOMMENDATIONS
Clinical Practice Guidelines for the Management of Overweight and Obesity in Adults
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Evidence-based statements Evidence level
Obesity in childhood and adolescence is a risk factor for III-2
obesity later in life.
The tracking of childhood obesity into adult obesity is stronger III-2
for older children than for younger ones.
Recommendation: level B
• When treating adults for overweight or obesity, the past history should
include height and weight in childhood.
Evidence-based statements Evidence level
Pregnancy and menopause are critical periods for weight gain III-2
in women.
It appears that a change in weight at menopause can be prevented II
by lifestyle change.
Hormone replacement therapy after menopause can result in II
reduced body-fat gain (particularly on the upper body)
when compared with a placebo.
Certain life events—for example, marriage, holidays, and giving IV
up sport—can have an influence on body fatness.
Quitting smoking can cause significant weight gain—on I
average 5 to 6 kilograms in the first year.
Recommendation: level B
• Instituting a weight-loss program at the time of quitting smoking may

the population level and can be used to estimate the relative
risk of disease in most people. However, it is not always an
accurate predictor of body fat or fat distribution, particularly
in muscular individuals, because of differences in body-fat
proportions and distribution.
Recommendation: level B
• Interpret BMI with caution when this is the only measure of body fatness
in a person, particularly when measuring older people and muscular,
mesomorphic individuals such as athletes.
Evidence-based statement Evidence level
Waist circumference is a valid measure of abdominal fat III-2
mass and disease risk in individuals with a BMI less than 35.
If BMI is 35 or more, waist circumference adds little to the
absolute measure of risk provided by BMI.
Recommendations: level B
• To reduce the risk of disease, Caucasian men should aim for a waist circumference
of less than 102 centimetres and women less than 88 centimetres. In Asians and
Indians the target could be 10 centimetres lower, and in Pacic Islanders it could
be signicantly higher.
• If patients wish to be measured, a combination of BMI and waist circumference,
or weight and waist circumference, should be used.
EVIDENCE-BASED STATEMENTS AND RECOMMENDATIONS
Clinical Practice Guidelines for the Management of Overweight and Obesity in Adults
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EVIDENCE-BASED STATEMENTS AND RECOMMENDATIONS
Clinical Practice Guidelines for the Management of Overweight and Obesity in Adults
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Recommendations: level D
• Both weight and waist circumference should be used to assess relative changes
in body fatness over time.

Clinical Practice Guidelines for the Management of Overweight and Obesity in Adults
xxi
Statement
As a complex disorder with multiple causes, obesity often Expert opinion
calls for multi-disciplinary attention.
Recommendations: level D
• If needed, clinicians should seek assistance from health professionals in other
disciplines with specialist knowledge in obesity management.
• The health benets and personal costs involved in weight loss vary considerably
between individuals, so consideration of treatment should take into account the
number of quality life-years to be gained, co-morbidities, the potential for successful
change, and the patient’s motivation.
Statement
There is no single effective treatment for long-term Expert opinion
weight loss. Lifestyle changes underlie all currently
effective treatments and should be emphasised.
T RE AT ME N T: E N ER GY I N TA K E
The effectiveness of any changes to eating behaviour depends on the
energy imbalance produced by a reduction in energy intake relative
to energy expenditure. There are many ways of achieving this, although
some of them are potentially dangerous.
Evidence-based statement Evidence level
The main requirement of a dietary approach to weight I
loss is a reduction in total energy intake.
Recommendation: level A
• A reduction in total energy intake remains the basic mechanism whereby all dietary
weight loss occurs. Evidence to date shows that low-fat ad libitum diets can result
in long-term weight loss. Other strategies have shown short-term effectiveness but
have not yet been assessed for long-term effect.
Evidence-based statements Evidence level

and success is more likely if behavioural or drug therapy is
used as a follow-up.
Recommendation: level B
• Very low energy diets can result in quick, short-term weight losses, but they
should be closely monitored and should not be used for extended periods.
Behavioural or drug therapy as a follow-up increases the likelihood of maintaining
some of the weight loss.
Evidence-based statement Evidence level
Use of meal replacements for one to five years can II
produce weight losses of 3.0 to 9.5 kilograms and significant
improvements in several co-morbid factors in overweight
and obese people.
Recommendation: level B
• Clinically significant weight loss can be achieved using meal-replacement programs.
EVIDENCE-BASED STATEMENTS AND RECOMMENDATIONS
Clinical Practice Guidelines for the Management of Overweight and Obesity in Adults
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EVIDENCE-BASED STATEMENTS AND RECOMMENDATIONS
Clinical Practice Guidelines for the Management of Overweight and Obesity in Adults
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Statement Evidence level
There is curently no long-term evidence supporting the use Long-term
of 'popular'diets (for example, low-carbohydrate diets and evidence
single-food diets). Some diets—such as those involving modified not available
fats, increased protein and a low glycaemic index—show
promise in short-term studies. No long-term data are available.
Although epidemiological studies show little relationship between III-I
alcohol intake and BMI in men, and even an inverse relationship
in women, experimental studies suggest that alcohol energy
is additive to the normal diet, and that it contributes

EVIDENCE-BASED STATEMENTS AND RECOMMENDATIONS
Clinical Practice Guidelines for the Management of Overweight and Obesity in Adults
xxiii
Evidence-based statement Evidence level
Lifestyle-based increases in physical activity—as opposed II
to a structured exercise program—are likely to be more
successful for weight loss in the long term.
Recommendation: level B
• Patients should be advised to comply with the National Physical Activity Guidelines
and the National Dietary Guidelines as a minimum requirement for body-weight
maintenance.
Recommendations: level C
• Lifestyle-based changes that increase the physical activity volume signicantly above
the baseline level are likely to be the most successful for long-term weight loss.
• Patients should be encouraged to increase their physical activity level in order to gain
associated health benefits, even in the absence of significant losses in body weight.
Evidence-based statement Evidence level
There is no single ‘best’ exercise for weight loss. Resistance III-1
training may provide benefits in terms of retention of lean body
mass, but it offers no apparent extra advantages, for either
weight loss or fat loss, over accumulated aerobic activity.
Recommendations: level D
• Depending on initial tness, health status, personal preferences, and lifestyle, any
of several types of physical activity may be the right one for a particular individual.
• It is important to prescribe physical activity that a patient prefers and is therefore
likely to maintain in the long term.
• For very immobile obese patients, a reduced weight-bearing form of activity
(such as swimming, walking in water, or cycling) may be best in the early stages
of a weight-loss program, until their fitness increases and weight-bearing activities
(such as walking) can be more easily carried out.

that associated with no treatment at all.
Recommendation: level B
• Physical activity should be a component of any weight-loss program, particularly for
improving the effectiveness of weight maintenance.
T RE AT ME N T: B E HAV I O UR A L TH E R A PY
Behavioural therapy can increase the effectiveness of other weight-loss treatments;
the duration of the therapy is related to the extent of weight-loss maintenance.
Evidence level
Overall, behavioural therapy used in combination with II
other weight-loss approaches can induce a mean weight
loss of about 5 kilograms, although this is variable
(0 to 13 kilograms). Three to five years after intervention
ceases, weight loss falls to about 3 kilograms (0 to 10 kilograms).
Recommendation: level B
• For optimal results, aspects of behavioural therapy should be combined
with nutrition and physical activity.
EVIDENCE-BASED STATEMENTS AND RECOMMENDATIONS
Clinical Practice Guidelines for the Management of Overweight and Obesity in Adults
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EVIDENCE-BASED STATEMENTS AND RECOMMENDATIONS
Clinical Practice Guidelines for the Management of Overweight and Obesity in Adults
xxv
Evidence-based statements Evidence level
Long-term (more than a year) behavioural therapy used in II
combination with other weight-loss interventions can be
associated with reductions in abdominal fat, even in the absence
of weight loss.
Behavioural therapy can
• improve compliance with dietary and physical activity requirements II
• reduce blood pressure II

kilogram more than placebo), but are currently indicated only
for short-term use.
Some SSRI (selective serotonin re-uptake inhibitor) II
antidepressant medications can result in weight loss in some
people under well-controlled conditions, although the effect
may be transient despite continued use of drugs.
Sibutramine can lead to a weight loss of 5.6 kilograms or about I
6 per cent (4.3 kilogram more placebo), and improve some co-morbid
factors after one to two years of treatment. If it is preceded by, or
combined with, lifestyle and dietary modifications, weight loss in some
individuals can almost double, to 10.8 kilograms, ranging from 5 to
17 kilograms (4 to 5 kilogram above placebo), or about 10.7 per cent.
The safety of prolonged (more than two years) therapeutic
use of sibutramine has, however, not been demonstrated.
The medication should be used with caution in patients
with a history of hypertension, and its use is not recommended
in patients with coronary artery disease, arrhythmias,
congestive heart failure, or stroke.
Orlistat combined with a low-energy, low-fat diet can I
lead to a weight loss of 8.4 kilograms ranging from 6 to
13kilograms (1.1 to 4.5 kilogram above placebo), or about
8.6 per cent, and improve some co-morbid factors after one
to two years of treatment. Two-thirds of this weight loss is
the result of diet modification.
A recently completed study published in abstract format Level of evidence
has shown efficacy and safety in patients over a four-year yet to be assigned
treatment period.
Both sibutramine and orlistat can increase the likelihood I
of long-term maintenance of weight loss while the drug
is being taken.

in the incidence and severity of some of the co-morbidities
associated with obesity (particularly diabetes) and improved
quality of life.
Obesity surgery may prove cost-effective in morbidly obese IV
patients after two years.
In patients with acceptable operative risks, mortality as a III-2
consequence of bariatric surgery is low. Bariatric surgery is,
however, often associated with impaired absorption of micronutrients,
which requires lifelong monitoring and often folate or vitamin B
supplementation.
Recommendation: level B
• Assessing both peri-operative risk and possible long-term complications
is important; the risk-benefit ratio should be assessed in each case.