Balance the food you eat with physical activity to maintain or improve your weight. Many Americans gain weight in adulthood, increasing their risk for high blood pressure, heart disease, stroke, diabetes, certain types of cancer, arthritis, breathing problems, and other illness. Therefore, most adults should not gain weight. If you are overweight and have one of these problems you should try to lose weight, or at the very least, not gain weight. If you are uncertain about your risk of developing a problem associated with overweight, you should consult a health professional

How to maintain your weight
   In order to stay at the same body weight, people must balance the amount of calories in the foods and drinks they consume with the amount of calories the body uses. Physical activity is an important way to use food energy. Most Americans spend much of their working day in activities that require little energy. In addition, many Americans of all ages now spend a lot of leisure time each day being inactive; for example, watching television or working at a computer. To burn calories, devote less time to sedentary activities like sitting. Spend more time in activities like walking to the store or around the block. Use stairs rather than elevators. Less sedentary activity and more vigorous activity may help you reduce body fat and disease risk. Try to do 30 minutes or more of moderate physical activity on most – preferably all – days of the week.
   The kinds and amounts of food people eat affect their ability to maintain body weight. High-fat foods contain more calories per serving than other foods and may increase the likelihood of weight gain. However, even when people eat less high-fat food, they still can gain weight from eating too much of foods high in starch, sugars, or protein. Eat a variety of foods, emphasizing pasta, rice, bread, and other whole-grain foods as well as fruits and vegetables. These foods are filling, but lower in calories than foods rich in fats or oils.
   The pattern of eating may also be important. Snacks provide a large percentage of daily calories for many Americans. Unless nutritious snacks are part of the daily meal plan, snacking may lead to weight gain. A pattern of frequent binge-eating, with or without alternating periods of food restriction, may also contribute to weight problems.
   Healthy weight ranges for adult men and women of all ages are shown in the chart above. See where your weight falls on the chart for people of your height. The health risks due to excess weight appear to be the same for older as for younger adults. Weight ranges are shown in the chart because people of the same height may have equal amounts of body fat but different amounts of muscle and bone. However, the ranges do not mean that it is healthy to gain weight. The higher weights in the healthy weight range apply to people with more muscle and bone.
   Weights above the healthy weight range are less healthy for most people. The further you are above the healthy weight range for your heights, the higher your weight-related risk. Weight slightly below the range may be healthy for some people but are sometimes the result of health problems, especially when weight loss is unintentional.