Extra pounds can mean extra years.
Both skinny and obese people have higher risks of premature death than people who are considered "overweight," according to a recent study in the Journal of the American Medical Association. "Overweight," according to this study, means a body-mass index (BMI) of 25 to 29.9: For a 5'6" woman, that's between 155 and 185 pounds. Calculate your own BMI here.

Dieting can be bad for your health.
When scientists observed nearly 3,000 overweight Finnish twins, they saw that those who had previously dieted were more likely to die during the 18 years of the study than those who simply maintained the same weight. Researchers suspect that yo-yo dieting places so much stress on your body that it can outweigh the benefits of slimming down.

Guys think you're hotter.
A woman is most attractive when her BMI is 20.85, according to a British study that asked people their perceptions of women of different weights. That's not heavy (a 20.85 BMI equals about 129 pounds for a 5'6" woman), but it is bigger than most celebs, whose BMIs often register under 18 (that's less than 112 pounds for a 5'6" woman). Women who weighed more than that ideal were considered to be less attractive - but super-skinny girls were rated lowest of all.

People like you better than if you're ultra-thin.
Very slender women can be perceived as "annoying," says Cheryl Dellasega, Ph.D., author of Mean Girls Grown Up: Adult Women Who Are Still Queen Bees, Middle Bees, and Afraid-to-Bees. "To anyone who's not so slim, the skinny girl can be a walking reminder of all our struggles with our own bodies," she says. But average-weight women, or even those slightly above their ideal weight, may be able to escape that type of negativity.

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