Study links disrupted stress hormones to higher obesity risk

A new study by researchers at Weill Cornell Medicine has found that obesity may not be linked to diet alone, as it can also result from disruptions in the body's daily rhythm of stress hormones.

The study explained that the type of obesity determines how the body handles fat and insulin, with hormone-related obesity differing from that caused by a high-fat diet.

Study details and experiments on mice

The research team conducted experiments on mice, comparing the effects of a high-fat diet with disruptions to the daily rhythm of glucocorticoid hormones, which regulate the body's stress response and various metabolic processes.

The results showed that mice exposed to disrupted hormone rhythms developed obesity even without consuming a high-fat diet. In these mice, fat was mainly stored in adipose tissue, while the liver was less prone to fat accumulation.

By contrast, a high-fat diet led to greater overall fat buildup and significant fat accumulation in the liver. When both factors were present, the mice recorded the highest levels of fat accumulation.

Effects on insulin resistance

The study noted that insulin resistance in mice with disrupted hormone rhythms appeared mainly in muscle tissue, while adipose tissue continued to respond to insulin and store fat. This may help prevent fat buildup in the liver.

These findings support a previous 2022 study by the same team, which showed that disrupting glucocorticoid hormone rhythms led to significant fat gain in mice without increased food intake.

Implications for humans and need for further research

Previous human studies have indicated a link between disrupted cortisol rhythms and obesity, especially among people experiencing chronic stress or working night shifts.

Study lead Dr. Mary Teruel emphasized that obesity is not a single condition with one cause, and that insulin resistance may vary depending on the affected tissue and underlying factor. The researchers highlighted the importance of understanding other contributors to obesity, such as sleep disruption, stress, and the timing of hormonal signals, and called for further studies to determine how these findings apply to humans.