Losing weight and staying fit is certainly an unending struggle, especially
for women. A recent study suggests that there could be a reason why females
find it more difficult to lose weight than men.
Researchers say hormones responsible for regulating appetite, physical
activity and energy expenditure work differently in the sexes.
‘Sex difference in physical activity, energy expenditure and body weight is driven by a specific source of protein in the brain.’
The teams from the University of Aberdeen, University of Cambridge and the University of Michigan, used a
mouse model to study how weight gain differs in each sex depending on physical
activity and energy expenditure.
During the study, researchers were able to transform obese male into lean,
healthy mice, but the same transformation did not occur in the female mice.
"Cells in this brain region make important brain hormones called
pro-opiomelanocortin (POMC) peptides that are responsible for regulating our
appetite, physical activity, energy expenditure and body weight.
In female mice the hormones only regulated appetite - they did not have the
extra benefits. This study reveals that a sex difference in physical activity,
energy expenditure and body weight is driven by a specific source of brain POMC
This could have broad implications for medications used to combat obesity,
which at present largely ignore the sex of the individual.
Professor Lora Heisler, Rowett Institute of Nutrition and Health, University
of Aberdeen said, "The World Health Organisation reports higher rates of obesity
in women worldwide, reaching twice the prevalence of men in some parts of the