Although no one is without health risk—even the fittest person can have a heart attack, diabetes, or cancer—health and well-being are apt to be in less jeopardy if BMI, body shape, and family health history do not indicate problems.

However, if your BMI is 25 or more, if your fat is primarily located in your upper body, and if you have a personal or family history of diabetes, heart disease, high blood pressure, or sleep apnea, losing weight can greatly improve your health. Keep in mind that BMI and waist circumference are just starting points.

Other factors also are important. When in doubt, seek a medical evaluation by your physician. A thorough history, examination, and blood studies can clarify whether your weight is having adverse effects on your health. The appropriate plan of action then can be tailored to meet your individual needs.

Losing body fat and keeping it off are not easy. Losing weight and then maintaining a healthful weight require collaboration with knowledgeable health care professionals. Obesity is not only a medical issue but also is a lifestyle issue.

Your habits can help you maintain a desirable body weight or they can hamper your efforts to lose weight or even cause you to gain further weight. The types and amounts of food you eat and the exercise you perform will determine whether you gain, lose, or maintain your weight.

Therefore, experts recommend that any weight loss program should consist of three main components: nutrition, exercise (or activity), and behavior modification.

Nutrition

Liquid meals, over-the-counter diet pills, and special combinations of foods promising to “burn” fat are not the answers to long-term weight control and better health. Learning to eat differently—to enjoy a well-balanced diet of fewer calories— is the best strategy to achieve health and weight goals.

You should begin by substituting the words “healthful nutrition program” for “diet.” Most people try to lose weight by eating 1,000 to 1,500 calories a day. In many instances, eating fewer than 1,400 calories makes it difficult to eat a balanced diet containing the recommended levels of nutrients.

Therefore, nutrition programs that are too low in calories may be hazardous to your health. You can lose weight by eating fewer calories or by increasing exercise. A caloric deficit of 3,500 calories is required to lose 1 pound of fat.

Over 7 days, this can be achieved by cutting 500 calories each day from your usual food intake or by cutting 250 calories each day (such as one or two fewer cookies) and burning an additional 250 calories with exercise (such as by walking briskly for 30 minutes).

The good news is that a relatively small loss of weight can make a big difference in reducing the risk of health complications from obesity. Even a 10 percent weight loss can lead to improvement in your blood sugar level, lipid values, and blood pressure.

Once this degree of weight loss has been achieved, further weight loss goals can then be set, if needed. Rather than aiming for an “ideal” weight, which may not be achievable or desirable, focus on achieving and maintaining a healthful weight.

A healthful diet for controlling weight includes foods from all food groups in the Food Guide Pyramid—ensuring balance and variety—in sensible amounts. It is helpful to review the energy density of the food consumed. Fat contains 9 calories/gram, protein 4 calories/gram, and carbohydrates 4 calories/gram.

Alcohol contributes 7 calories/gram. For most people, the volume of food consumed determines how full you feel. Therefore, eating a small amount of an energy-dense food (such as fat) is usually not filling, whereas eating a large enough amount to fill you up results in a very large calorie intake.

To lose weight, decrease your total calories by cutting back on the fat while filling up on low-calorie high-nutrient foods such as vegetables, fruits, and grains. You also can eat lower-fat versions of foods. However, be careful, because low-fat is not always lowcalorie.

Healthful eating habits also avoid the feast or famine phenomenon. Distributing food selections throughout the day provides nourishment to support daily activities and can help to eliminate energy highs and lows. Three meals and occasional snacks also keep one’s appetite in check.

It is also important to avoid the hazards of repeatedly losing and gaining weight. Although repeated dieting is still a matter of debate, some studies suggest that it may lower the rate at which calories are burned.

When a person is off the diet and more food is eaten, the body stores fat faster and more efficiently. This effect causes regain of the lost weight. In this circumstance, the amount of weight regained often is more than that lost in the first place.

Physical Activity

Improved eating habits in combination with decreased calorie intake and calorie-burning exercise is the best way to lose weight and maintain the results. In addition to enhancing weight loss efforts, physical activity promotes loss of body fat, increases muscle mass, and increases cardiovascular fitness.

Regular exercise not only helps you lose weight by increasing the number of calories you burn but also makes it easier to keep off the weight that you have already lost. Walking is a good choice for getting started on an exercise plan. A daily 2-mile walk burns approximately 1,000 to 1,200 calories per week.

In addition, do not discount the physical activity that is part of ordinary activities of daily living—housework, climbing stairs, gardening— all important forms of exercise that can contribute to weight loss. It may be easier to maintain a schedule if you exercise with a friend. Many experts recommend that you also participate in resistance (or strength) training.

Resistance training can increase your muscle mass (which, as discussed previously, increases your basal metabolic rate), your bone density (which can help protect against osteoporosis), and your balance and coordination (which can lower the risk of injury), and it can help improve your posture.

People who are overweight, have been inactive, or have medical problems should check with their physician before starting an exercise program. An exercise stress test may be helpful because it can measure the response of the heart to exercise and help establish a safe starting level.

Behavior Modification

Behavior modification programs help identify triggers and treatments for unhealthful eating habits—such as uncontrolled snacking or late night eating. Such programs often explore the reasons behind an inactive lifestyle.

Food diaries and activity logs frequently are used to heighten your awareness of what and how much is eaten and the type and amount of exercise done daily. These journals often provide insight into what triggers undesirable eating and what can be done to avoid or change this behavior.

Other key behavioral elements needed for success include: Commitment—There must be personal motivation to change—to eat healthfully and to get regular physical activity. Priorities—It takes significant mental and physical energy to change deeply ingrained habits.

If other major issues or life stresses are present, it is important to seek help for dealing with them. When balance in life is regained, you can focus on healthful nutrition more effectively. Realistic goals—The best goals are those that can be achieved. Set daily or weekly goals that allow progress to be measured and rewarded.

Aim to lose about 1 to 2 pounds weekly. It is important to know that small losses of weight— or improvements in physical activity—can improve health. Measurements of blood pressure, blood sugar level, and blood cholesterol and triglyceride values are more important in terms of health than the number on the scale.

Accept the fact that there will be setbacks. Instead of becoming frustrated or angry, resume your health program once again. Group support—Joining with people facing the same challenges can promote sharing of ideas and facilitate commitment.