weight loss diet We have two types of fat, white and brown. White fat is the troublesome fat in our bellies, hips, thighs, and elsewhere. White fat stores calories in the unlikely event that you won’t have enough to eat in the future. It was useful for our ancestors who had to rely on an uncertain food supply. It helped them survive famines, but it’s less helpful for most of us who rarely miss a meal. The other type, brown fat, doesn’t store calories but rather burns them to create heat.
Brown fat is found in hibernating animals and human babies. Babies, who don’t have much hair for insulation, use brown fat to cope with the change in temperature after birth. The brown fat uses calories to produce heat keeping babies warm until they adjust to the temperature outside the womb. After the baby acclimates, the proportion of brown fat decreases so there’s not much left in adulthood. You probably retain some remnants of brown fat in your upper chest and neck.
Cold increases brown fat activity. Research suggests that less brown fat activity is associated with a higher BMI. If you could activate your brown fat, it’s likely that you’d burn more calories which might help with weight control. One National Institutes of Health review of the research concluded that being cold could use an extra 25 to 400 calories per day. Cold also increases glucose and lipid disposal which might help in treating diabetes. Still, the researchers at the NIH meeting concluded that more research is needed, it’s too early to tell if cold stimulation would be a useful strategy for weight loss.
If you’d like to experiment you don’t need to move to Antarctica or live in an igloo to activate your brown fat. Over time small reductions in the temperature of your environment could add up. A recent study found that two hours at 66 degrees Fahrenheit (19 C) was helpful.
As I’m writing this it’s 95 degrees in Northern California and we’ve been told to cut back air conditioning to avoid overloading the power grid so blasting the air conditioning isn’t a great idea. Still, when the weather gets cooler you might consider putting away your long johns and turn the thermostat down a few degrees. Shivering isn’t necessary and you don’t have to freeze but you’ll save on your energy bill and the cooler temperature just might help with weight control.
Cypess, A.M., Haft, C.R., Laughlin, M.R., & Hu, H.H. (2014). Brown fat in humans: consensus points and experimental guidelines. Cell Metabolism 20, 408–415.