Yo-yo dieting and middle age waistlines
A number of sportsmen and women have to compete in a weight
class (rowers, boxers, judokas etc), an aspect of sport that has
major implications for weight control. In most of these sports, a
bodyweight near the maximum permitted for a particular class is
advantageous; a common practice, therefore, is to shed weight
before the ‘weigh-in’ in order to drop a few pounds to dip under
the maximum permitted weight. The downside of this practice is
that it tends to lead to ‘weight cycling’ – periods of significant
weight gain, which then require later dieting and weight loss.
In the general population, studies have shown that repeated
cycles of weight gain followed by dieting and weight loss tends to
increased BMI (Body Mass Index – a measure of fatness related
to height). The theory is that during the dieting phases, lean
muscle tissue is shed along with body fat. This muscle loss
lowers the resting metabolic rate so when normal eating is
resumed, fat gain occurs more easily than had that individual not
dieted in the first place. One question that some researchers
have asked is whether a history of weight cycling for sport leads
to an increased risk of weight gain once an athlete has retired,
and this is what French researchers have been investigating in a
To do this, 136 retired French athletes who participated in
major international competitions in weight class sports (rowers,
wrestlers, boxers, and judokas) were included. On average, the
athletes had been retired from sport for 22 years. The subjects’
former and current body mass and height were recorded. Also
recorded was information about their dietary habits during their
sports careers (ie how many times a year they had to weight
cycle and how much weight they typically had to lose). In
addition, the subjects’ current physical activity levels were
investigated as well as their current eating habits and attitudes
towards food. The researchers collated the data and then looked
for correlations between their current BMI and the type of sport
the retired athletes had pursued, the number of weight cycles
and their current activity levels.
The first finding was that the recorded weight changes did not
seem to depend upon the amount of time elapsed since
retirement. Overall, between the ages of 18 and 50 years the
athletes’ average increase in BMI was 3.2kg/metre2. This
compares favourably with the typical increase in the same age
group of the general population, which is around 4.2kg/metre2.
Secondly, the increase in BMI that was observed did not appear
to be linked to number of diets that an athlete had followed
during his or her career. A third finding was that the retired
athletes were currently spending around 4.8 hours a week doing
physical activity – significantly higher than the levels reported in
the general population.
The evidence gathered from retrospective studies where
correlations are sought is never as solid as a properly constructed
clinical trial. However, this study seems to suggest that weight
cycling in an earlier sporting career does not automatically lead
to a greatly increased risk of BMI gains in later life. One thing to
bear in mind, though, is that in this study, the athletes had
maintained high levels of physical activity since retirement, and
this probably played a major role in keeping their waistlines trim!
BMC Public Health. 2013 May 27;13(1):510.
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