Nutrition research shows all body fat isn’t created equal

photo of Michelle Foster
Michelle Foster (click to enlarge)

What makes one fat deposit “good” and the other so “bad”?

This question has inspired the research of Department of Food Science and Human Nutrition assistant professor Michelle Foster, who studies the behavioral differences between visceral fat (central body or belly fat) and subcutaneous fat (fat on the lower abdomen, rear and legs).

With obesity-related diseases like hypertension and type 2 diabetes more prevalent in those with visceral fat, Foster is investigating why certain fat deposits carry a higher risk for these diseases. Research has shown that subcutaneous fat, considered “good fat” or “protective fat,” is not associated with the same health risks. By removing different fat deposits, Foster can see what the fat’s effect is on the entire body.

Foster has studied fat deposits in mice to better understand why certain fat deposits cause health issues. By studying two groups of mice – one group with gradual accumulation of body fat being fed a Western diet (butter and sugar) and a lean group fed a chow diet (low-fat) – Foster learns how the body reacts to subcutaneous fat removal. When fat is removed from one part of the body, fat redistribution occurs and can potentially affect several different tissues within the body.

‘Protective’ fat

Supported by a Colorado Nutrition Obesity Research Center grant and the National Institute of Diabetes and Digestive and Kidney Disease within the National Institutes of Health, Foster’s research has revealed that subcutaneous fat protects the muscle closest to it. Mice that had “protective” subcutaneous fat removed from their legs had a decline in glucose tolerance and increased insulin resistance, as well as higher fat content in leg muscles close to the area of fat removal.

“We learned that the subcutaneous leg fat was protecting the muscle,” Foster explains. “When it was removed, the muscle next to the missing fat increased its fat storage and had a decline in insulin sensitivity.”

The behaviors of certain fats will provide insight into glucose intolerance and insulin resistance in patients with high amounts of visceral fats. Foster’s research is beginning to focus on mechanisms for gaining visceral fat and how to avoid the growth of these fat deposits.

“Body fat regulation is all about how fat deposits communicate with one another,” says Foster. “By understanding this communication, we can hopefully learn how best to decrease the bad fat and promote the good.”

Foster’s research appeared in the journal Adipocyte.