You've been sweating away on the elliptical for months and obsessing over your diet (kale again?), and the scale is at a standstill. Meanwhile, your husband announces his desire to get in shape. He swears off beer and voilà —two weeks later, his spare tire is gone. What gives?
Unfortunately for us, "weight loss is stacked in favor of men on account of differences in hormones, metabolism and muscle mass," explains Sean Bourke, MD, co-founder of JumpstartMD, a group of medical weight-loss clinics in the San Francisco Bay Area. Thanks to a biological edge (think more testosterone—which helps build muscle, which in turn helps burn more calories), men will lose 1 to 2 more pounds a week than women who are the same age and starting weight if they're following the same routine, Dr. Bourke says.
Still, that doesn't mean you have to stand back and let him be the biggest loser. Learn the science behind men's seemingly random strategies, and you can optimize them for your own body.