And on the flip side, it’s all too easy to gain weight eating low sugar, low calorie health food, or eating mostly protein, if you eat too much of it. In fact, some studies have shown that for some people, exercise and healthy eating can lead to weight gain. Why ?Because it can encourage people to reward themselves with too many extra snacks or treats. Not that eating mostly junk food is a good idea, even if you eat portions small enough to avoid weight gain. Do that and you’ll be lacking important nutrients found in other foods. So in the end, balance is important for general health. But if losing weight is your goal, the solution is simple: whatever you eat, eat less of it.