We’ve excerpted a section on calorie-burning brown fat from George L. King, M.D.’s Reverse Your Diabetes in 12 Weeks, which aims to help you avoid, control, and even reverse Type 2 diabetes. To read more about the method, click here. 

Brown fat is a special type of body fat, found in small amounts in most (and perhaps all) people, that burns calories at a very high rate when activated by cold temperatures or other triggers—as much as several hundred calories a day. Some scientists believe that if we could all learn to activate our brown fat on a regular basis, it could help put an end to America’s obesity epidemic.

3 Ways to Increase Your Own Brown Fat Activity

Although some people have dismissed brown fat as a biological novelty, I believe its promise as an important tool for fighting type 2 diabetes and obesity is very real. If someone is able to burn an extra two or three hundred calories per day, that’s enough to shed a pound of body fat in just a couple of weeks. As Americans get older, we typically add ten pounds of weight per decade. The calorie-burning boost from brown fat could be enough to reverse this weight gain and help older individuals maintain the body weight they had as young adults. By revving up metabolic activity, brown fat could also help combat the metabolic slowdown that occurs when people start dieting—the set point phenomenon described previously, which is one of the most difficult obstacles to losing weight.

Activating your brown fat is probably not going to bring someone from an obese state to a healthy body weight on its own, but if brown fat activation is combined with exercise and diet, it could make a major difference in terms of helping the one fourth of the U.S. population who are significantly overweight drop down to a normal, healthy weight.

One thing that’s clear from studies done so far, though, is that you have to find a way to trigger activity in your brown fat cells in order to experience their calorie-burning effect. On the other hand, as Dr. Cypess has shown in his cool-vest experiments, under the right conditions, activation of your brown fat can occur very quickly. Here are some suggested ways to stimulate your own brown fat cells to begin burning calories. As always, I want to stress that everyone’s physiology is slightly different and that some of these approaches may work better for you than others.

1. Expose Your Skin to Cooler Temperatures

The most proven way to activate brown fat is to expose your skin to relatively cool temperatures. Colder temperatures send a signal to your brain, which then acts to stimulate brown fat activity in two ways: by acting on your vascular system directly to increase blood flow to your brown fat stores and by sending nerve impulses to brown fat cells that stimulate an additional boost in cellular activity.

How cool do you have to be? In addition to their studies with vests containing 57°F water, Drs. Kahn and Cypess have also found that sitting in a 59°F room for two hours wearing summer clothing will stimulate brown fat to burn an extra 100 to 250 calories, depending on the individual. A Japanese research team put subjects in an even milder setting of 66°F, and found that more than half of subjects under age thirty-eight showed signs of brown fat activation. (For the over-thirty-eight group the results were less impressive, with fewer than 10% showing any brown fat effect.) In another study conducted by a group of Canadian researchers, subjects wearing a suit containing tubes filled with 64°F water burned about 250 extra calories over three hours, most of which appeared to be the result of increased brown fat activity.

What to Do

These experiments indicate that lowering the thermostat of your residence to the mid-60s or below may be enough to stimulate at least some brown fat activity. You can also activate your brown fat by dressing more lightly in cool weather. For people willing to expose themselves to even cooler temperatures, a number of cooling vests are available. Research is also now underway to investigate whether exposing just one part of the body to cooler temperatures (by wearing a cooling band around your arm or leg, for example) might be enough to stimulate brown fat activity.

Activity Tip: You can boost the amount of calories you burn during exercise by stimulating your brown fat stores during your workout. Make a point of exercising in relatively cool temperatures—62°F to 64°F or lower. Making sure your skin is exposed while you’re exercising may be even more beneficial because the evaporation of sweat as you exercise adds to the cooling effect. What you don’t want to do is try to increase how much you perspire by turning up the heat when you’re exercising because this hotter environment will actually shut down brown fat activity.

2. Eat foods that may activate your brown fat

Although there’s no firm evidence that any specific foods or nutrients can activate brown fat, it’s interesting to note that radiologists—who want to decrease brown fat activity when doing scans of cancer patients because the heat generated by activated brown fat makes it harder to see tumor-related activity—routinely recommend that patients eat a high-fat, low-carbohydrate diet before such scans, on the grounds that this reduces brown fat activation. This suggests, of course, that eating a low-fat, high-carbohydrate diet will boost brown fat activity.

In addition, animal studies have found that the herb bitter melon appears to increase activity of brown fat and that ursolic acid—a substance that occurs in high concentrations in apple peels—increases brown fat and muscle mass, while at the same time reducing obesity and improving glucose tolerance. Other foods containing ursolic acid include cranberries, blueberries, plums, and prunes, as well as the herbs oregano, thyme, lavender, holy basil, bilberry, devil’s claw, peppermint leaves, periwinkle, and hawthorn. Ursolic acid is also available in supplement form.

3. Exercise

Although the benefits of exercise for your cardiovascular health, glucose control, and weight management are well known, researchers are now discovering that working out may have a positive effect on brown fat activity as well: Studies have found that irisin, a newly identified hormone that is produced during exercise, actually works to convert white fat into a variation of brown fat known as beige fat.

These findings show that both brown and beige fat can burn calories and, even more exciting, that the two types of fat are activated in different ways—with cool temperatures inducing brown fat to become active and exercise transforming white fat into beige fat. This suggests that there are actually multiple ways to increase your calorie-burning fats and reduce the amount of unhealthy, calorie-storing white fat in your body.