Scientists at Florida State University say that while overeating (hyperphagia) and sedentary behaviour are known risk factors for obesity, research in these areas - especially overeating - has been studied almost exclusively in males.
They set out 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.
Consumer organisations and governments are pushing food makers to help tackle the global obesity epidemic. According to the World Health Organisation, approximately 300 million people worldwide are believed to be obese and a massive 750 million overweight. A growing body of science suggests that obesity significantly increases the risk of heart disease, diabetes and other life-threatening conditions.
From this latest animal study Lisa Eckel and Shelley Moore conclude 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.
For the study, male and female 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.
"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 per cent increase), relative to sedentary males (9.1 ± 2.2 per cent increase)."
Full findings of the study "Diet-induced hyperphagia in the rat is influenced by sex and exercise" are available on the online edition of the American Journal of Physiology - Regulatory, Integrative and Comparative Physiology.
There are signs that the 'sweet tooth', for whatever sex, may becoming more cautious, driven by a desire to eat more healthily.
Growth in confectionery across Europe is slated to slow down with value sales likely to reach £3.9 billion by 2007, an increase of just 4 per cent from 2003 value of £3.7 billion, according to market analysts Datamonitor.
"This is very much a consequence of the maturity of the western markets. Major manufacturers have experienced declining value sales," said John Band, consumer markets analyst at Datamonitor.