A new study from the University of Aberdeen claims that the hormones regulating appetite and energy expenditure work differently between the sexes, making it more difficult for women to lose weight.
Photo via Flickr user Frédéric BISSON
With more than half of the UK population classified as either overweight or obese (and the rest most likely guilt-cramming health foods), maintaining a healthy weight in these food-saturated times is a universal struggle.
And yet the cliched image of the perpetually dieting, weight-worried individual is almost always female. Entire industries are built on female-targeted diet products and GettyImages heaves with photos of women holding cupcakes and looking guilty.
But could the old trope of the woman struggling to lose weight while her boyfriend happily devours a family-sized pizza without gaining a pound be more than just a cultural stereotype?
A new study from the University of Aberdeen claims that the hormones responsible for regulating appetite and energy expenditure work differently in men and women, making it more difficult for women to lose weight.
Using mice to examine how weight gain differs between the sexes depending on physical activity and energy expenditure, researchers were able to turn obese male mice into lean, healthy specimens. This transformation didn't occur in their female counterparts.
According to the study, this could be down to POMC peptides: neurons in the brain responsible for controlling appetite, increasing energy expenditure, and encouraging movement. Researchers found that female mice only had the hormones that regulate appetite, making weight loss more difficult.
The University of Aberdeen's professor Lora Heisler, who led the study said: "What we have discovered is that the part of the brain that has a significant influence on how we use the calories that we eat is wired differently in males and females."
This could be why some obesity medication such as lorcaserin, which targets the chemicals in the brain linked to appetite, has less of an impact on women.
Working with teams from the University of Cambridge and the University of Michigan, the researchers tested this theory on mice.
Heisler explained the outcome: "While the subset targeted by obesity medication lorcaserin influences appetite in both males and female mice, in males, this subset has the added benefit of also modulating physical activity and energy expenditure. In female mice, this source of POMC peptides does not strongly modulate physical activity or energy expenditure."
She added that while medications that target POMC peptides may reduce appetite in women, they will not "tap into the signals in our brain that modulate physical activity and energy expenditure."
Heisler hopes that the study's findings will lead to more effective, sex-specific ways of treating obesity in women, which the World Health Organisation reports is more prevalent than in men.
She said: "This could have broad implications for medications used to combat obesity, which at present largely ignore the sex of the individual."
While higher rates of obesity in women can also be linked to social factors such as financial income and access to healthy food options, the research at least offers a new approach to tackling the burgeoning "obesity crisis."