You watch every morsel you put into your mouth, you hit the gym with unflinching regularity and you haven’t missed a yoga class in six months. Why aren’t you losing weight?

We all know that exercise alone can’t help you lose weight but perhaps your gender is to blame!

A study, carried out at Rowett Institute of Nutrition and Health at the University of Aberdeen, has revealed that weight loss is more challenging for women than men. The researchers say this is because the hormones that regulate the appetite, physical activity and energy expenditure work differently in both sexes. The study was published in the journal Molecular Metabolism and could lead to the development of new sex-specific obesity medications.

The University of Aberdeen team partnered with teams at the University of Cambridge and the University of Michigan for the study. They used a mouse model and examined how weight gain differs in each sex based on physical activity and energy expenditure. As part of the study, researchers could transform obese male into lean healthy mice, but could not manage the same transformation in female mice.

Current obesity medications stimulate the production of pro-opiomelanocortin (POMC) peptides in the brain. These peptides are responsible for regulating the appetite, physical activity, energy expenditure and body weight.

But not every POMC neuron performs the same function.

Researchers found that the hormones only regulated appetite in female mice; they did not have the extra benefits.

Professor Lora Heisler, who led the study, has said: “So while medications targeting this source of POMC peptides may effectively reduce appetite in females, our evidence suggests that they will not tap into the signals in our brain that modulate physical activity and energy expenditure.”

What this essentially means is that women’s brains are not wired for weight loss. This makes losing those kilos tougher in spite of the same amount of dieting and exercise as compared to men.

But Heisler believes that this discovery could change the way obesity is tackled through targeted medication. “This could have broad implications for medications used to combat obesity, which at present largely ignore the sex of the individual,” she said.

“Currently, there is no difference in how obesity is treated in men and women. However, 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,” she has said.

Women and weight loss don’t seem to go hand in hand. A 2015 study has revealed that birth order may influence a woman’s weight. The research showed that firstborn women are slightly more likely to be overweight or obese as adults as compared to their younger sisters.