Dietary Approaches to Overweight
JOANNA MCMILLAN-PRICE, MD
JENNIE BRAND-MILLER, MD
Abstract. For years dietary guidelines for the treatment of overweight and obesity have advised a low-fat, high carbohydrate diet.
Recent meta-analyses have shown that weight loss achieved with ad libitum low-fat diets is typically in the range of 3–4 kg.
Although clinically significant, this weight loss is modest, usually regained on cessation of the intervention and the low-fat
messages have not impacted on the ever increasing rates of overweight and obesity. Alternative approaches include low-glycemic
index and high protein diets. Both effectively reduce the glycemic load of the diet and early studies suggest they may be effective
in increasing satiety, reducing ad libitum energy intake and may improve fat oxidation by reducing insulin demand. Both
approaches can be used within the context of a reduced-fat diet, with evidence emerging to suggest this may improve weight and
body composition outcomes.
ates of obesity and overweight remain on the
increase in most Western countries despite the
well-intentioned efforts of millions of individu-
als. Effective action by governments and health care
providers has not been effective and may have even
been counterproductive. In the United States, Europe,
and Australia, more than 40% of adults are now over-
weight or obese, a rate almost double that of the previ-
ous few decades.
The underlying reasons for this
global pandemic are complex. Although genetic suscep-
tibility plays a part, changes in gene frequency cannot
explain the dramatic rise in obesity rates over the last
10–15 years. The combination of reduced physical ac-
tivity; an abundance of easily available, affordable, en-
ergy-dense, overly palatable food; and social and eco-
nomic influences has likely contributed to the rising
prevalence. There are currently a myriad of dietary
approaches to treat and prevent overweight and obe-
sity, as witnessed by the sheer number of popular diet
books and regimens. The conventional approach used
by dietitians, physicians, and public health authorities
has been to concentrate on reducing the total fat in the
diet, replacing the fat with carbohydrate-rich foods.
This approach has come under increasing scrutiny in
recent years, however, and various alternatives, includ-
ing low–glycemic index diets and high-protein diets,
have been proposed. This article gives an overview of
each of these different approaches and reviews the
evidence and hypotheses for each.
Reducing fat intake has been the primary focus of di-
etary prevention and treatment of overweight and obe-
sity for more than 20 years. The basis of this advice is
simple—namely, that because fat has more than double
the energy per gram than carbohydrate or protein, a
reduction in fat intake will result in a reduced energy
intake. Moreover, dietary fat is efficiently stored as
body fat and may also lower energy expenditure, via a
lower thermogenic (food-induced energy expenditure)
effect compared with that of carbohydrate or protein.
Finally, high-fat foods are relatively less satiating than
equal-calorie portions of high-carbohydrate or high-
Four meta-analyses of controlled trials comparing
low-fat diets with normal-fat diets as a control and
under ad libitum conditions consistently showed that
reduction of dietary fat without restriction of total en-
ergy intake causes a reduction in energy intake and
weight loss in a dose-dependent fashion, and may pro-
duce modest weight loss in overweight subjects.
Many, but not all, epidemiologic studies support these
findings and demonstrate that relatively high dietary
fat intake corresponds with increased obesity rates.
Typical weight losses produced by ad libitum low-fat
diets are in the range of 3–4 kg. Although clinically
significant, these losses are modest, and weight is fre-
quently regained on cessation of the intervention. How-
ever, some have suggested that this is an underestimate
and that losses are greater in those who comply more
fully with the dietary recommendations. Swinburn et
stratified subjects according to compliance and
found that the range of weight loss ranged from 1 kg in
the poorly compliant group to about 6 kg in the most
compliant group over 1 year. Nevertheless, in all sub-
jects weight regain occurred as soon as the intervention
From the Human Nutrition Unit, School of Molecular and Microbial
Biosciences, University of Sydney, Sydney, Australia.
Address correspondence to Dr. Jennie Brand-Miller, University of Syd-
ney, School of Molecular and Microbial Biosciences, Human Nutrition Unit,
Building G08, Sydney NSW 2006, Australia.
E-mail address: firstname.lastname@example.org
© 2004 by Elsevier Inc. All rights reserved. 0738-081X/04/$–see front matter
360 Park Avenue South, New York, NY 10010 doi:10.1016/j.clindermatol.2004.01.010