When talking about body fat, you likely lament those areas of excess cellular collection — such as your saddlebags, belly pooch and side-boob areas. This overage can be annoying when it comes to physique goals, and excessive amounts of fat are hazardous to your health.
But not all body fat is bad news, and you are host to a spectrum of adipose tissues, including white, brown and beige varieties. And while having too much of certain kinds can increase your risk for disease, other kinds have the exact opposite effect.
First things first: Body fat and dietary fat are not the same thing. “Dietary fat is a calorie-dense macronutrient found in food, while body fat is [energy] stored in the human body,” explains Corey Phelps, an NASM-certified personal trainer and nutritional expert. Healthy dietary fat comes from foods such as olive oil, avocado and nuts, and it assists with a host of metabolic functions, including metabolism, nutrient transport, and hormone creation and regulation.
White Fat (WAT)
Body fat, for the most part, is the physical manifestation of stored energy — extra ingested calories that the body did not have an immediate use for at the time of their consumption and that are now in holding cells (literally) until it’s time to burn them off. This kind of fat is called white adipose tissue, or WAT, and is what composes that cringe-worthy subcutaneous bulge you see in high-def when trying on a body-hugging garment. WAT contains fewer mitochondria — the brown, calorie-burning powerhouses of cells — making the tissue appear white.
But while unsightly, WAT actually has several functions within your body: It insulates and protects your organs, regulates body temperature and balances hormones such as cortisol, growth hormone and leptin. However, where you store WAT on your person is of primary concern, especially if your body tends to house it viscerally — around your organs. An excess of visceral fat is associated with metabolic dysfunction, heart disease, cancer, Type 2 diabetes and other serious conditions.
Brown Fat (BAT)
Brown adipose tissue, or BAT, is the subject of many current studies, and for a while, it was believed that only babies harbored this kind of fat, which helped them to stay warm. But as it turns out, human beings of all ages have BAT, which is found along the front and back of your neck and in your upper back. Because it contains a lot of mitochondria, BAT is brown in appearance, and unlike WAT, BAT is a highly active tissue, and its purpose is to generate — not store — energy: When you’re cold, BAT fires up to generate heat within your body, which in turn burns a ton of calories and contributes to a leaner body composition, improved blood sugar control and reduced overall bodyweight. In other words, the more BAT you have, the leaner you will be.
According to the Endocrine Society, women are more than twice as likely as men to have substantial amounts of brown fat. Experts theorize that because women tend to have less muscle mass overall, they need more brown fat to generate heat and keep warm.
While someone may carry about 20 or 30 pounds of white adipose tissue, they only house about 2 to 3 ounces of brown fat. But those few ounces have the potential to burn 300 to 500 calories a day!
The amount of brown fat you have may decrease as you age, but there are several ways to increase and activate this kind of fat:
Turning down the thermostat or going outside in cooler weather can help activate brown fat and even boost its production: Studies published in the New England Journal of Medicine found the sweet spot for BAT activity landed between 61 and 66 degrees. This is where the mitochondria kick in and contribute to the calorie burn, heating you up from the inside out to maintain a normal body temperature.
Sleep On It
Sleep has also been shown to boost BAT production: The more melatonin you produce as a result of quality sleep, the more activated brown fat you have and the higher your calorie-burning capacity, according to a study published in the Journal of Pineal Research.
Feed Your Fat
Some foods take more energy to digest than others, and brown fat appears to play a role in heat generation because of muscle activity in the intestines and other digestive processes, according to researchers from the Technical University of Munich. That same study found that eating a carbohydrate-rich meal had the same thermogenic effect — and activation of brown fat — as did exposure to cold.
Work It Out
Exercise can contribute to the reduction of white adipose tissue, but it also can stimulate the conversion of white fat cells to brown cells: Evidence suggests that exercising boosts uncoupling protein 1, a protein that is present only in brown and beige fat cells, which redirects the energy flow in mitochondria so they produce heat, according to research published in Nature Medicine.
There is a third kind of body fat that exists in pockets within white adipose tissue called beige fat. This specialized tissue contains more mitochondria than WAT but less than BAT, giving it a beige appearance. According to a study published in the International Journal of Obesity, beige cells have the ability to harness heat production by incinerating excess glucose, and more recent research published in PLOS Biology found that blocking certain hormones can boost the activity of beige fat and increase its potential to burn energy.
Brown and beige fat cells have thermogenic properties, meaning they burn rather than store calories.
Besides working to increase your brown-fat percentage, you also can try to boost your beige, further improving metabolism, body composition and overall health:
The best way to boost your beige fat cell percentage is to exercise. The hormone irisin is secreted from muscles in response to exercise and actually converts white fat cells to beige, effectively turning them into furnaces rather than storage units. And according to research, the best form of exercise to increase irisin production is high-intensity interval training.
Studies show that performing aerobic exercise two to three times per week can help decrease visceral fat without dieting.
Cuckoo for Cocoa
Outside of exercising, a very recent study published in the June 2019 issue of Molecular Nutrition & Food Research suggests that supplements also might be of use: Scientists discovered that the phenolic compounds in cocoa bean shells can cause the browning of white fat cells, and further studies are being done to determine whether these shells can help assist in the fight against obesity.