35. You down a sports drink after your 30-minute workout

THE RESULT: More liquid calories than you need.

THE FIX: Sports drinks contain carbohydrates and electrolytes, such as sodium, potassium, and chloride, and are designed to rehydrate and keep energy levels high. Electrolytes assist in cellular function and regulate fluid balance—life-saving in cases of severe fluid loss. They’re also lost through sweat during exercise. How-ever, unless you’re active at a high intensity for more than 60 minutes per workout or are exercising in very hot conditions, you don’t need sports drinks. Water and a balanced diet will keep you hydrated and supply all the electrolytes you need. If you’re concerned about calories— and that’s one reason you’re at the gym in the first place—read the labels. To provide bona fide energy, a drink must contain calories, and that usually means sugar. Some beverages have two to three servings per bottle. If you drink the whole bottle, that can easily translate to more than 200 calories, which could be more than you burned during your workout.