Water Retention After Exercise Since water weighs something, you may notice temporary weight gain after exercise. Don't get too concerned about this water weight, though, because it's not that you're gaining fat, which is what we're really concerned about when it comes to your health.

Trust us, nothing works better than resistance weight training if your goal is to build a healthy muscle mass. In fact, several studies including the one published in the Journal of the American Medical Directors Association, found that skinny women quickly gained muscle when they did weight training regularly.

To lose weight, exercise more or eat fewer calories than is recommended. To gain weight, increase the number of calories you eat while maintaining a moderate activity level. Read more about making smart food choices and find recommendations of how much to eat, organized by activity level.