New research out of the University of Kentucky suggests that cold temperatures can trigger the body to burn calories. More specifically, exposure to cold can convert white fat tissue from the thighs and belly to what’s known as beige fat. This type of fat actually burns calories to generate heat.
However, researchers say that this biological response (known as browning fat tissue) is blunted in those who are obese.
“Browning fat tissue would be an excellent defense against obesity,” study author Philip A. Kern, M.D. said in a statement. “It would result in the body burning extra calories rather than converting them into additional fat tissue.”
To see if people showed more evidence of browning during cold-weather months, researchers took a close look at samples of fat tissue taken from 55 different people in the winter and compared them to samples taken in the summer. They found that belly fat tissue had elevated levels of genetic markers for beige fat. This was even stronger in the thigh tissue samples.
This suggests a seasonal effect of fat browning – but this effect was hampered in obese people.
The idea that cold weather may aid in weight loss is nothing new. But the findings do shed light on how the process might be different for obese people. Previous research out of UC San Francisco found that shivering actually leads to weight loss. Another 2013 study suggests that spending time in a 60-degree room at increasing intervals over a 10-day period may aid in weight loss in a similar way. A different study found that people who spent time in a 63-degree room for two hours a day over a six-week period actually decreased their body fat mass by roughly 5 percent.