Sydney: Severe diets don't necessarily lead to binge eating and could be used
to treat obesity without risking the disorder, according to new
research from the University of Sydney's Charles Perkins Centre and the University of Western Sydney. The
surprising discovery suggests that severe diets, such as those
involving meal-replacement shakes, don't necessarily exacerbate
binge-eating behaviour. The findings could provide additional
treatment options for health professionals, who have generally hesitated
to prescribe such extreme diets for obese patients due to concerns
about potential adverse effects on eating behaviour.
"Intuitively,
one would expect that such extreme diets would result in compensatory
binge eating," said lead author of the study Associate Professor Amanda Salis from the University of Sydney's Charles Perkins Centre and Boden Institute of Obesity, Nutrition, Exercise & Eating Disorders.
"However,
most studies showed that for people who were obese and binge eating
before the diet, their binge eating actually declined during and just
after the diet.
"For people who were obese and did not have any
binge eating behaviour before the diet, some studies showed no change in
binge eating, while other studies of lower quality showed a transient
increase in binge eating, usually just after the diet, in 10 to 15 per
cent of dieters."
Published online in Obesity Reviews,
the research involved a systematic review of clinical trials that
measured binge eating before and after semi-starvation diets in people
with obesity and people who did and did not have problems with bingeing
before the diet.
"When clinically supervised, low or very low
energy diets are an important treatment option for obesity. The results
from this study show that these diets are not necessarily a trigger for
binge eating, although eating behaviour should be monitored during their
use," Associate Professor Salis said.
The diets under
investigation replaced meals and snacks with nutritionally balanced
products, typically in the form of shakes. Such diets are called low
energy diets when they deliver less than 5000 kilojoules per day, and
very low energy diets when they deliver less than 3300 kilojoules per
day. This is less than 20 to 50 per cent of the daily energy
requirements of most people who are obese.
Associate Professor
Salis emphasises that while these extreme diets come with the advantages
of rapid weight loss and practicality, they are only recommended for
people with a body mass index in the obese range (30 and over), or those
with a body mass index of 27 or more who have risk factors for
cardiovascular disease.
"An important caveat is that the long-term
consequences of extreme diets on binge eating are unknown, as all but
one of the studies we reviewed followed participants for less than 18
months," she said.
"Also, all of the extreme diets under
investigation were done within the context of carefully controlled
clinical trials, which is completely different from 'do it yourself'
starvation diets without clinical supervision, which have been linked to
binge eating."
To fill the gap in knowledge of the
long-term effects of very low energy diets, Associate Professor Salis is
seeking post-menopausal women from the Sydney metropolitan area for a
clinical trial of the long-term (three-year) effects of semi-starvation
versus conventional diets on binge eating behaviour in obesity. Women
with or without binge eating behaviour are required.
For more information, contact Associate Professor Salis' team ontempo.diet@sydney.edu.au