Illustration: Joel Holland
To keep your metabolism in gear, you need to combine exercise with simple dietary changes. For starters, eat 200 fewer total calories a day than you did in your 20s. (That means 1,800 to 2,200 calories, depending on how active you are.) Make sure your diet includes metabolism-boosting foods like peppers; research subjects who took a supplement with a compound like the one that gives chilies their spice burned about 100 extra calories a day. And don't forget to load up on protein (a minimum of 46 grams daily), which requires at least twice as many calories to digest as carbs. Try this tuna-vegetable wrap for a protein-packed meal with a kick.