A team of researchers in Japan has discovered a key biological reason that may help explain why women tend to burn more calories from fat than men, a finding that could help pave the way for new treatments for obesity and related diseases.

The study, published Monday in the journal Nature Communications, was led by researchers at the Institute of Science Tokyo in collaboration with the University of Tokyo.

While men typically have a high proportion of muscle that helps them burn more calories in total, recent studies have shown that women burn more calories from fat specifically. For this study, the team focused on brown adipose tissue (known as BAT), a special type of fat in the body that burns energy to produce heat. Previous studies have shown that women have more active BAT than men and are less likely to develop Type 2 diabetes or other metabolic disorders. But until now, the reason behind this difference was unclear.

Using mice, the researchers found that a protein called PGC-1alpha plays a key role in boosting calorie consumption in females. The protein helped power up mitochondria 〞 the parts of cells that turn nutrients into energy, commonly referred to as the powerhouse of the cell 〞 in their bodies by encouraging the production of specific fats that support mitochondrial function. The result was more energy burned as heat.

When the scientists removed the PGC-1alpha protein, female mice showed a sharp drop in mitochondrial performance and calorie-burning ability, while male mice were largely unaffected. This suggests that PGC-1alpha works in a female-specific way to enhance fat metabolism.

The study also revealed that estrogen, the primary female sex hormone, works together with PGC-1alpha to activate genes involved in fat processing. In female mice, this combination triggered higher levels of key molecules that help BAT burn calories.

By mapping these differences at the molecular level, the researchers were able to show that women may have a built-in advantage when it comes to energy expenditure linked to both hormones and genetic regulators.

While the current findings are based on animal models, scientists say the results could help explain why women are typically less prone to weight-related conditions and may lead to new therapies that target calorie-burning mechanisms.

※The findings of this study provide a new understanding of sex differences in energy metabolism,§ the team said in a statement. ※This is a breakthrough achievement ... that could help elucidate mechanisms of obesity and contribute to the development of new methods and drugs to restore metabolic health.§