Science says fat is bad, right? Not really. Body fat can boost your sex drive, fend off a chill, and more


Fat gets a bad rap. Studies have shown that carry too much weight can increase your risk of heart disease or add inches to your waistline-but not all body fat is evil.

Case in point: Adipocytes, fat cells that reside under the skin, appear to protect your body against infection, according to researchers from the University of California, San Diego. They believe that adipocytes trigger the production of immune cells known to kill bacteria and other harmful microbes.

But fat's good for more than immunity. Here, four other reasons to love a little padding. (And in the meantime, read about five other Things You Don't Know About Body Fat.)

It Boosts Your Sex Drive

"When your body fat percentage is too low, your sex drive has a tendency to plummet," explains Jessi Kneeland, a trainer at Peak Performance Gym in New York City. But too much body fat can also put a damper on libido (and body confidence), Kneeland notes. For women, the American College of Sports Medicine says anything from 20 percent to 32 percent is considered to be satisfactory for good health, though depending on how fit you are, you can dip down as low as 12 percent. To help you figure out where you stand, check out The Best And Worst Ways to Measure Body Fat.

It Keeps You Warm

A healthy amount of body fat acts sort of like another layer of clothing, keeping you toasty, says Kneeland. The "good" type of fat-brown fat-is especially good at generating heat. But again, she warns, too much body fat will also backfire, making you feel sweaty or overheated with little exertion.

It Delivers Nutrients to Your Body

"We know that low body fat negatively effects the delivery of vitamins to your organs and throughout your body," says personal trainer Cathy Leman, M.A., R.D., L.D., owner of NutriFit, Inc. She's talking about fat-soluble vitamins like A, D, E, and K, which are stored in your body's fatty tissue.

It Aids with Fertility

Fat is good for the entire reproductive system-from having a normal menstrual cycle to getting pregnant, says Leman. If you maintain too low of a body fat percentage, she adds, you may experience menstrual irregularities. (Low body fat is a key risk factor for the Female Athlete Triad, a health problem that occurs when you're not eating enough to sustain your activity level, leading to irregular periods, loss of bone density, and nutritional deficiencies.) If you're a gym rat and your menstrual cycle becomes erratic, see your doc. Learn about 10 Other Everyday Things That Can Affect Your Period.