Those extra pounds should be avoided at all costs, right? Actually, while being overweight isn't generally good for our health, not all fat is created equal-some may even be beneficial.
There are two major kinds of body fat. White fat, the most abundant type, is what you feel when you squeeze your midsection. Brown fat, found mainly in the neck region, burns energy rather than storing it the way white fat does. Brown fat may also help avoid diabetes. According to a study in Cell Metabolism, individuals with higher amounts of brown fat had smaller changes in blood sugar and thus a reduced risk of developing diabetes. Infants have high levels of brown fat, which helps regulate their body temperature. Sadly, we lose it as we age, and adults have only small amounts.
Adults can increase brown fat by exposing themselves to cold temperatures. In a recent study, people who slept in a mildly cold room (about 66 degrees F) increased the amount and activity of their brown fat by up to 40 percent. Sleeping in mild warmth (81 degrees F), however, decreased their amount of brown fat. Cold showers don't seem to affect it.
Brown fat does have its drawbacks. Radiologists don't like it, because the heat it causes makes it harder for body cans to detect activities in patients. Although there's no firm evidence that any specific foods or nutrients can activate brown fat, radiologists routinely recommend that patients eat a high-fat, low-carb diet before scans on the grounds that this reduces brown fat activation.
Just as brown fat isn't perfect, neither is white fat all bad. Even though people tend to hate it, white fat delivers important health benefits. It protects our vital organs, helps keep us warm, and stores calories for later use, keeping us from starving when food is scarce.
White fat can sometimes be turned into brown-it's then called beige or brite ("brown in white") fat. Like brown fat, beige fat burns energy and can thus help fight against obesity. Scientists are still trying to figure out how the change happens; one study points to a hormone called irisin, which our muscles produce when we exercise.
Fat cells' sensitivity to temperature changes means there's more than one way we can get rid of unwanted fat. Cooling treatments, for instance, freeze fat cells to death. The body removes these damaged cells over several months.
