People with higher concentrations of brown fat in their bodies have better blood sugar control, higher insulin sensitivity, and a better metabolism for burning off fat.

The findings, made by researchers at the University of Texas Medical Branch at Galveston, suggest brown fat has the ability to help the body fight diabetes.

"We showed that exposure to mild cold raised whole body energy expenditure, increased glucose removal from the circulation and improved insulin sensitivity in men who have significant amounts of brown adipose tissue depots," said UTMB's Labros Sidossis, professor of Internal Medicine, Division of Geriatric Medicine. "These results support the notion that brown adipose tissue may function as an anti-obesity and anti-diabetic tissue in humans."

People have two types of fat: white and brown. Excessive white fat tissue is associated with negative health effects such as decreased insulin sensitivity, which contributes to diabetes.

The new study, published in the journal Diabetes, compared men with either low or high levels of brown fat on their resting energy expenditure, glucose usage and insulin sensitivity. The men were placed in either an environment with a normal temperature or a mildly cold temperature for between five and eight hours. The team collected body and breath samples to observe changes in glucose and insulin concentrations. They also looked at the differences in cellular energy production and gene expression in both the brown and white tissue samples.

"In this study we show that, when activated via mild cold exposure, brown adipose tissue can increase energy expenditure and burn calories. This is good news for overweight and obese people," said Sidossis. "Of even greater clinical significance maybe the finding that brown fat can help the body regulate blood sugar more effectively. This is great news for people with insulin resistance and diabetes and suggests that brown fat may prove to be an important anti-diabetic tissue."