In the past few years, researchers have discovered that, like khakis at the Gap, fat comes in many different shades—each with unique molecular properties and health implications. From reddish brown to beige, fat is more complicated than we might think. What does the fat rainbow mean for you? Here’s everything you need to know.
Brown fat: Good
Brown adipose tissue is found in the back of the neck, and serves to convert food to heat. It acts like a muscle when stimulated by cold environments, burning calories for fuel. An adult of normal or below-normal weight naturally stores about 2–3oz of brown fat—enough to burn 250 calories over the course of three hours when stimulated. As for standing in a cold shower to lose weight, it could work, but “shivering yourself skinny” has yet to be proven effective.
Beige fat: Good
At least in mice, this mix of brown and white fat shows huge potential for weight management. According to the Dana-Farber Cancer Institute, when mice exercise their muscle tissue releases the hormone irsin, which converts white fat into brown fat. Since humans have the same hormone in their blood, researchers suspect that humans also produce beige fat through exercise. This fat stores the energy that would otherwise wind up in your belly.
Subcutaneous white fat: Neutral
Dubbed “the inch you can pinch,” this kind of white fat lies directly under the skin. A study published in the New England Journal of Medicine in 2004 found that liposuction removal of subcutaneous fat (up to 23lbs of it) in 15 obese women had no effect after three months on their blood pressure, blood sugar, or cholesterol. So while a muffin top might not be on your list of fashion do's, it’s not high on the list of health don’ts. It’s not making your abs any more visible, though.
Visceral white fat: Bad
This “deep fat” wraps around the inner organs and gives off toxins and fatty acids that are swept up by the blood and dumped into the liver. Research suggests that visceral fat pumps out chemicals that can increase the risk of cardiovascular disease by promoting insulin resistance and chronic inflammation. Because of its rich blood flow, visceral fat is very responsive to exercise—far more so than stubborn subcutaneous fat.