Brown fat, a fatty tissue that burns sugar and fat and that has shown to be linked to obesity, may be linked to ethnicity as well, The Huffington Post reports. A study in The Lancet recruited 12 caucasian men and 12 men of South Asian decent and looked at activity of brown fat in the two groups. The men were placed in a very cold environment to the point of shivering so that their brown fat would begin to burn fatty acids and glucose for warmth. They were then injected with radioactively labeled glucose which clung to brown fat and showed up on a PET scan. Researchers found that “South Asian participants not only used 32 percent less energy than the Caucasian group, but their brown fat was also 34 percent smaller in volume.” The study has important implications for a genetic basis for obesity and may explain ethnic disparities in obesity rates.