Females May Be More
Susceptible To Overindulge “Sweet Tooth” Cravings Than Males
While
exercise decreases overeating in both sexes, less of a reduction is seen in
females
BETHESDA, Md. – It is well known that obesity has
reached epidemic proportions. As waistbands expand, so do the number of
health gurus heralding the benefits of portion control and exercise to keep
obesity at bay. But with some studies indicating that the rate of obesity
is greater in women than in men, could it be that women are at a
disadvantage when it comes to these obesity avoidance tactics? Is it
possible that females are predisposed to succumb to the temptation to
overeat? And could exercise be a less effective method of appetite
suppression in women than in men? Researchers at The Florida State
University say the answer could be yes.
Overeating (hyperphagia) and sedentary behavior are
known risk factors for obesity, but research in these areas – especially
overeating – has been studied almost exclusively in males. In the new
animal study “Diet-induced hyperphagia in the rat is influenced by sex and
exercise,” Lisa A. Eckel and Shelley R. Moore (The Florida State University
Program in Neuroscience and Department of Psychology) found that:
-
rats
overate when given access to a highly palatable diet containing a greater
portion of sugar than their normal diet
-
when
a sweet diet is freely available, female rats consumed more calories per
day than male rats
-
when
given a chance to exercise, overeating was reduced in both sexes of rats,
but
-
he
caloric intake reduction associated with the exercise was much less
dramatic in the female rats, and
-
unlike male rats, female rats exercised less when sweet foods were
available than when sweet foods were not available.
The researchers concluded that female rats are more
susceptible than male rats to over consume a palatable, sweetened diet, and
that female rats are less likely than male rats to use exercise as a means
to control appetite in the presence of such a diet.
The results of their study were published in the
American Journal of Physiology – Regulatory, Integrative and Comparative
Physiology (August 5, 2004 Article in Press).
Abstract
Rats increased their caloric intake
when fed a diet containing greater fat or sugar than that found in regular
laboratory chow. Because such diet-induced hyperphagia has been studied
primarily in sedentary male rats, the researchers’ goal was to investigate
the effects of gender and exercise on caloric intake of a diet (chow
supplemented with a supply of liquid sweetened condensed milk), chosen for
its ability to stimulate hyperphagia. Rats were housed individually in cages
that provided access to running wheels. Daily caloric intake of chow alone
and then chow plus sweet milk was monitored during sedentary and active
conditions.
In sedentary rats (where the
running wheel was blocked), chow intake was greater in males, compared to
females. In other phases, wheel running produced similar decreases in chow
intake in both sexes. Availability of the chow plus milk diet increased
caloric intake, compared to that observed in chow-fed rats. This
diet-induced hyperphagia was significantly greater in sedentary females
(35.7 ± 3.1% increase), relative to sedentary males (9.1 ± 2.2% increase).
Wheel running decreased intake of
the chow plus milk diet in both sexes. In active males, diet-induced
hyperphagia was abolished and caloric intake was reduced to that observed
during chow feeding. In active female rats, diet-induced hyperphagia was
attenuated, but not abolished, and caloric intake of the chow plus milk diet
remained greater than that observed during chow feeding. The researchers’
conclude that female rats are more vulnerable than male rats to this “sweet”
form of diet-induced hyperphagia.
Source:
The article “Diet-induced hyperphagia in the rat is influenced by sex
and exercise” is online in the
American Journal of Physiology – Regulatory, Integrative and Comparative
Physiology, and is scheduled to appear in
the November issue, published by the American Physiological Society.
A copy of the abstract is available to the public at
www.the-aps.org.
Editors’ note:
A copy of the research paper by Eckel and Moore is available to the media.
Members of the media are encouraged to obtain an electronic version and to
interview members of the research team. To do so, please contact Stacy
Brooks in the APS Communications Office (301-634-7253 or
sbrooks@the-aps.org).
Upcoming APS Intersociety Meeting:
INTEGRATIVE BIOLOGY OF EXERCISE MEETING -
Oct. 6-9, 2004 - Austin, Texas (Co-sponsored by the American
Physiological Society, Canadian Society for Exercise Physiology and the
American College of Sports Medicine. More information:
http://www.the-aps.org/meetings/aps/austin/index.htm)
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