Why Does Abdominal Fat Increase In Middle Age?

For years, the general belief was that weight gain with age was an inevitable and passive process. However, recent research published in Science challenges that idea: the body appears to intentionally “manufacture” abdominal fat in middle age thanks to the action of a previously unknown type of stem cell.

The study, led by the City of Hope Science Center in California, identified adipose progenitor cells activated in midlife (APCs) as responsible for this phenomenon.

These cells, far from decreasing their activity over the years, become more dynamic and promote the accumulation of visceral fat, a tissue linked to insulin resistance and metabolic diseases such as type 2 diabetes.

Mice, aging, and visceral fat

The experiments began with laboratory mice. Upon reaching 12 months of age—equivalent to middle age in humans—the males showed significant growth in their abdominal fat. More than 80% of the fat cells present in this area were newly formed, which surprised the researchers.

Furthermore, these animals showed a decrease in caloric expenditure and an increase in insulin resistance. Both factors are considered warning signs for the development of disorders such as obesity, metabolic syndrome, and cardiovascular problems.

The LIFR receiver, the key to the mechanism

One of the most significant discoveries was the identification of the LIFR (leukemia inhibitory factor receptor) as the key activator of APCs. When scientists blocked this signaling in mice, abdominal fat accumulation decreased significantly.

This discovery opens the door to future development of LIFR-targeted therapies to control age-related obesity, an approach that could transform the way we prevent abdominal fat and its health complications.

Beyond aesthetics: a health risk

The accumulation of fat in the midsection doesn’t just alter the body’s silhouette. According to Dr. Qiong Wang, co-author of the study, the truly worrying aspect is that “although body weight may remain stable, what changes is its composition: muscle mass decreases and internal fat increases.”

This invisible phenomenon on the scale increases the risk of chronic inflammation, cardiovascular disease, and metabolic decline, making it a public health issue rather than an aesthetic one.

From mice to humans: shared evidence

Although the bulk of the research was conducted in rodents, the specialists also confirmed the existence of these cells in human tissue. Even when transplanted into young organisms, the A-PCs maintained their ability to generate fat, indicating that their behavior is linked to the age of the cell’s origin and not to the environment in which it develops.

With this discovery, scientists are rethinking the relationship between aging and metabolism. The challenge now lies in designing new medical strategies that can prevent or slow the harmful effects of visceral fat at critical stages of life.