Washington, USA: A recent US scientific study has revealed a hidden factor driving obesity that may not be linked solely to diet but can also result from a disruption in the body's circadian rhythm of stress hormones.
A study conducted by researchers at Weill Cornell Medicine in the US suggests that the underlying cause of obesity can influence how the body processes fat and insulin, implying that obesity resulting from hormonal imbalances differs from obesity linked to a high-fat diet.
The researchers investigated this by conducting experiments on laboratory mice, comparing the effects of a high-fat diet with the effects of disrupting the circadian rhythm of glucocorticoid hormones that help the body regulate its stress response and various metabolic processes.
The findings showed that mice exposed to disrupted hormonal rhythms became obese despite not consuming a high-fat diet. However, they stored fat differently from mice whose obesity was diet-induced.
In the former group, fat accumulated mainly in adipose tissue, while the liver remained less prone to fat buildup. By contrast, a high-fat diet led to greater overall fat accumulation and was more strongly associated with fatty liver development.
When a high-fat diet was combined with hormonal rhythm disruption, the mice recorded the highest levels of fat accumulation.
The scientists also found during the study a difference in the way insulin resistance appeared; in mice that were subjected to hormonal rhythm disruption, insulin resistance was mainly concentrated in the muscles, while adipose tissue remained responsive to insulin and continued to store fat, which may help prevent fat from being redirected to the liver and accumulating there.
Dr. Mary Teruel, who led the research team, said: "We should stop treating obesity as one thing," adding that "We should stop treating insulin resistance as one thing too. Our preclinical results show that muscle, fat and liver can respond very differently to insulin depending on what is driving the metabolic change.”
"It’s not just how many calories they were eating. The timing of the hormonal signals changed how the body handled those calories and where the energy was stored," Teruel said.
The scientific findings concluded that obesity is linked to the circadian rhythm of the hormone cortisol, indicating that changes in this rhythm occur among individuals suffering from chronic stress or working shifts, factors beyond diet alone.
