Brown fat and why you want more
You have two types of fat in your body: White fat is the jiggly stuff that most of us want to lose, because it secretes hormones that tell the glands governing your metabolism to slow down and conserve energy. Brown fat, on the other hand, actually speeds your metabolism up.
Exercise is important on the Fast Metabolism Diet, and when I have clients who are stuck on a plateau, I ask if they’re exercising – and if they’re doing the right exercise on the right phase. Exercise is good for your heart, mind and metabolism, but here’s more motivation: Moderate exercise has been shown to spur the development of brown fat.
Brown fat vs. white fat
White fat is the fat under your skin (called subcutaneous fat) and around your organs (called visceral fat). White fat helps maintain your body temperature and protect your organs. White fat also secretes some hormones, and regulates the output of others, and these hormones communicate directly with the adrenals, the pituitary, and the hypothalamus.
White fat’s other purpose is to hang out in your body, storing energy “just in case” there’s an emergency. Your body protects itself by stashing energy in those fat reserves. When your metabolism slows down, your body produces even more white fat, packing it in around your butt, hips and belly.
Unlike white fat, instead of storing energy, brown fat seems to prefer to burn through it – it’s thermogenic. Brown fat also helps stimulate the metabolism by warming the body, increasing blood flow, and making it easier to deliver nutrients to the white fat. Brown fat also helps balance your lipids (your cholesterol and triglycerides), and move wastes through your body. Brown fat metabolizes and stores carbohydrates, storing them as glucose for your red blood cells and brain. And brown fat also releases hormones – hormones that prompt your body to burn off the white fat it had been keeping on hand as energy stores.
Where is my brown fat?
Until recently, scientists thought that only infants and young children had brown fat — but they’ve discovered that adults have it too, mostly around our shoulders blades, neck, spine, and around our collarbones. The leaner you are, the more brown fat you’re likely to have — but the really amazing thing is that under the right circumstances, your body can turn unhelpful white fat into metabolism-boosting brown fat.
Exposure to cold does the trick, probably because before babies develop the ability to shiver, they depend on brown fat to regulate their body temperature. You don’t have to be so cold that you’re shivering for your body to start developing brown fat; in some tests, a drop of about 5 degrees was enough to trigger the hormone-like proteins that create brown fat.
Moderate exercise has also been shown to develop your stores of brown fat. So when you go out for that workout, you’re giving your body exactly what it needs to keep your metabolism burning red-hot.
Mind you, we do all need some white fat to regular our body temperature and store energy in case of emergency; it’s having more than you need that throws your metabolism out of balance. And the more scientists learn about brown fat, the more it looks like this mitochondria-rich fat is the missing link that helps keep everything else in balance.