Why Guys Lose Weight Faster…

By Rob Medich

You and your man forge a pact: Together, you'll each drop pounds before bathing-suit season. Here's a tip: Do it his way. Because through a twist of biological and sociological fate, he's much more primed to succeed.

You've probably already noticed: He just gives up beer and -- bam! -- 10 pounds, gone. But why is it so much easier for him? First, there are the natural reasons: "Men have considerably more muscle than women," explains Adam Campbell, sports and nutrition editor of Men's Health magazine. "Muscle is the primary fat-burner in the human body, so if you have more, you can burn a greater amount of fat."

Second, women store more body fat for proper reproduction, according to sports nutritionist Cassandra Forsythe, a doctoral researcher at the University of Connecticut. "We need body fat to sustain a baby." And let's not forget, adds Campbell, "Men weigh considerably more than women. It takes a lot more calories to support the mass of a 225-pound man than it does to support that of a 150-pound woman."

Finally, "starting early on, boys are more physically active for the most part," says Forsythe. "The girls would play with Barbies, the guys would go out and climb in a tree fort." So while you can't change biology, you can adopt some of the following guy-like behaviors that foster weight loss:

Diet and Eat: "Women are more likely to go on a 'starvation' diet than men," says Campbell. "That quickly lowers their metabolism. So not eating is a bad approach for weight loss."

Go Pro: "Eat more protein," says Campbell. "Meat and eggs have long been considered guy foods, but they're packed with protein -- in particular, an amino acid called leucine, which is critical for boosting metabolism and preserving muscle." Adds Forsythe, "Women crave chocolates and sweets, which affects insulin and other fat storage hormones in your body and causes you to have a sugar crash and crave more food soon after."

Add Weights to Lose Weight: "Women should absolutely be lifting weights," says Campbell. "Weight loss is typically 75 percent fat, and 25 percent muscle. So if muscle's the primary fat-burner in the human body, and you lose it, then your progress will slow dramatically."

Get in It to Win It: "Men push themselves more than women," says Forsythe. "At the gym, women typically do an easy cardio session on some sort of cross-trainer while guys push themselves harder by running or sprinting and hitting the weights. Men are more aggressive, more competitive when they work out, when they play."

When it comes to weight loss, though, we know which sex is more determined.