Do you really need to exercise to lose weight?

No doubt you'll be frustrated if you go to the gym over and over again and get no results. A bunch of studies show that eating habits are the most critical factor in losing weight (and keeping it off), but a new study from St. Louis University says you shouldn't discount proper exercise. People who lost weight through cardio exercise alone or a range of cardio exercises lost the same number of calories (about 7 percent of their body weight over four months) as those on a diet.

But there's a big "BUT?" The first two groups lost more fat and retained more muscle mass - something that helps you burn more calories at rest, gives you more energy and can prevent injury. Try adding a moderate amount of walking, running, or biking to your plan (the group in the study we talked about did this for about four hours a week).