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 (box 5).
The kinds and amounts of food people eat affect their ability to maintain 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.
Maintaining weight is equally important for older people who begin to lose weight as they age. Some of the weight that is lost is muscle. Maintaining muscle through regular activity helps to keep older people feeling well and helps to reduce the risk of falls and fractures.
Healthy weight ranges for adult men and women of all ages are shown in figure 3. 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, even within the same weight range. 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 height, the higher your weight-related risk (figure 3). Weights slightly below the range may be healthy for some people but are sometimes the result of health problems, especially when weight loss is unintentional.
Research suggests that the location of body fat also is an important factor in health risks for adults. Excess fat in the abdomen (stomach area) is a greater health risk than excess fat in the hips and thighs. Extra fat in the abdomen is linked to high blood pressure, diabetes, early heart disease, and certain types of cancer. Smoking and too much alcohol increase abdominal fat and the risk for diseases related to obesity. Vigorous exercise helps to reduce abdominal fat and decrease the risk for these diseases. The easiest way to check your body fat distribution is to measure around your waistline with a tape measure and compare this with the measure around your hips or buttocks to see if your abdomen is larger. If you are in doubt, you may wish to seek advice from a health professional.
Being too thin can occur with anorexia nervosa, other eating disorders, or loss of appetite, and is linked to menstrual irregularity and osteoporosis in women, and greater risk of early death in both women and men. Many people -- especially women -- are concerned about body weight, even when their weight is normal. Excessive concern about weight may cause or lead to such unhealthy behaviors as excessive exercise, self-induced vomiting, and the abuse of laxatives or other medications. These practices may only worsen the concern about weight. If you lose weight suddenly or for unknown reasons, see a physician. Unexplained weight loss may be an early clue to a health problem.
You do not need to lose weight if your weight is already within the healthy range in the figure, if you have gained less than 10 pounds since you reached your adult height, and if you are otherwise healthy. If you are overweight and have excess abdominal fat, a weight-related medical problem, or a family history of such problems, you need to lose weight. Healthy diets and exercise can help people maintain a healthy weight, and may also help them lose weight. It is important to recognize that overweight is a chronic condition which can only be controlled with long-term changes. To reduce caloric intake, eat less fat and control portion sizes (box 6). If you are not physically active, spend less time in sedentary activities such as watching television, and be more active throughout the day. As people lose weight, the body becomes more efficient at using energy and the rate of weight loss may decrease. Increased physical activity will help you to continue losing weight and to avoid gaining it back (box 5).
Many people are not sure how much weight they should lose. Weight loss of only 5-10 percent of body weight may improve many of the problems associated with overweight, such as high blood pressure and diabetes. Even a smaller weight loss can make a difference. If you are trying to lose weight, do so slowly and steadily. A generally safe rate is 1/2-1 pound a week until you reach your goal. Avoid crash weight-loss diets that severely restrict calories or the variety of foods. Extreme approaches to weight loss, such as self-induced vomiting or the use of laxatives, amphetamines, or diuretics, are not appropriate and can be dangerous to your health.
Children need enough food for proper growth. To promote growth and development and prevent overweight, teach children to eat grain products; vegetables and fruits; low fat milk products or other calcium-rich foods; beans, lean meat, poultry, fish or other protein-rich foods; and to participate in vigorous activity. Limiting television time and encouraging children to play actively in a safe environment are helpful steps. Although limiting fat intake may help to prevent excess weight gain in children, fat should not be restricted for children younger than 2 years of age. Helping overweight children to achieve a healthy weight along with normal growth requires more caution. Modest reductions in dietary fat, such as the use of low fat milk rather than whole milk, are not hazardous. However, major efforts to change a child's diet should be accompanied by monitoring of growth by a health professional at regular intervals.
Try to maintain your body weight by balancing what you eat with physical activity. If you are sedentary, try to become more active. If you are already very active, try to continue the same level of activity as you age. More physical activity is better than less, and any is better than none. If your weight is not in the healthy range, try to reduce health risks through better eating and exercise habits. Take steps to keep your weight within the healthy range (neither too high nor too low). Have children's heights and weights checked regularly by a health professional.