How to Activate the Good Kind of Body Fat

When it comes to talking about weight loss and fat, the conversation usually goes in one of two directions. Either you’re discussing the benefit of adding healthy fat into a diet to lose weight, or you’re talking about decreasing body fat percentage, which some experts note can be a better way of tracking progress than overall weight or BMI.

But there’s a third, much less discussed, type of fat you should know: brown fat.

Although it’s not trackable in the same way overall body fat percentage might be, implementing strategies to boost your brown fat can be helpful for weight loss, according to Candice Seti, PsyD, licensed clinical psychologist, certified personal trainer and certified nutrition coach, who’s known as “The Weight Loss Therapist.”

“When we talk about body fat, we are almost always talking about white fat, or white adipose tissue,” she says. “It is the kind that sits right under our skin that we are always trying to reduce.” Part of this type of white fat, she adds, is visceral fat, which wraps around internal organs and can do significant damage, especially to your cardiovascular system.

But brown fat, or brown adipose tissue, lies mainly in the neck and shoulder region, and only makes up a few ounces of body weight. What it lacks in mass, though, it makes up for in power.

“Brown fat creates heat, in a process called thermogenesis, which burns calories in the process,” Seti says. “In fact, brown fat can create more heat than any other substance in the body and burn a massive amount of calories in the process.”

Everyone is born with a big store of brown fat, but it decreases as we age. Experts have noted that babies are more susceptible to cold than adults because of immature nervous system development, less body hair and less muscular development — for example, they can’t shiver as a way to warm up. So, the brown fat helps babies regulate heat until they get older.

Just because you may have long ago outgrown your baby brown fat stores doesn’t mean you can’t turn on the brown fat furnace you have now, though. Here are five main strategies for activating that big-time calorie burner:

Exposure to cold is the number 1 way to build brown fat, because your body needs to heat itself in response to the cold, and it will recruit other available fat if possible.

That means when you get cold, your body may switch white fat to brown, which increases your calorie burn rate. There’s no need to risk hypothermia to get the effect, either. You can just turn the thermostat down, stay outside longer when it’s cold out or spend a few seconds at the end of your shower in cold water instead of hot.

Brown fat can be created when the body reaches a satiation point when eating, says Seti. Aim for a comfortable, satisfied feeling after eating. If you’re still a little hungry, you may not have eaten enough to kick on your brown-fat transformation.

Plus, the more you work on eating the right amount, the better this process becomes. Recent research found brown fat works with a certain hormone in the gut to control hunger signals (see number 4 below). So it can actually help you develop better habits when it comes to selecting the right portions.

Maybe the old saying should get revised to “an apple a day keeps the pounds away.” Just make sure you’re including the peel.

Apples with the peel offer ursolic acid, a natural compound that’s been shown not only to increase brown fat, but also to increase muscle mass and strength. This is particularly important for weight loss because muscles also burn calories at a faster rate, so you’re getting a two-fer calorie burner with one humble apple.

Preliminary research in mice found secretin, a gut hormone released after a meal, interacted with brown fat to signal fullness to the brain. Secretin also acted as an appetite suppressant to increase the amount of heat brown fat produced. It’s important to note mice have more brown fat than humans, says Eric Ravussin, PhD, associate executive director for clinical science at the Pennington Biomedical Research Center, who studies the subject.

“Secretin secretion is sensitive to nutrients, so eating the right starter could be helpful in promoting satiation and result in reduced meal size and caloric intake,” adds study co-author Martin Klingenspor, PhD. Some evidence shows oleic acid, found in foods like olive oil, meat, cheese, nuts and sunflower seeds, helps boost secretin levels. While more research in humans is needed, it’s possible eating foods that activate secretin could help burn an extra 50–150 calories per day, he says.

There are tons of reasons to include more physical activity in your day, from improved mood to better memory to lower risk of chronic conditions and reduced risk of obesity. Now you can add “brown fat creator” to the list.

“This one should be a no-brainer as it’s on the list for everything health related,” says Seti. “But this may be beneficial here because of an enzyme called irisin. This enzyme is released when we exercise and it has been shown to convert white fat cells to brown.”

But be sure not to exercise in the heat, she adds. That actually prevents the activation of brown fat, so do your workout in the coolest temperature possible.

Originally published September 2019, updated with additional reporting by Jodi Helmer