Obesity

Definition

Obesity is a term used to describe body weight that is much greater than what is considered healthy. If you are obese, you have a much higher amount of body fat than is healthy or desirable.

Adults with a body mass index (BMI, calculated as weight in kilograms divided by height in meters squared) greater than 25 kg/m² but less than 30 kg/m² are considered overweight.

Adults with a BMI greater than 30 kg/m² are considered obese.

Anyone who is more than 100 pounds overweight or who has a BMI greater than 40 kg/m² is considered morbidly obese.

Alternative Names

Morbid obesity; Fat - obese

Causes, incidence, and risk factors

Consuming more calories than you burn leads to being overweight and, eventually, obesity. The body stores unused calories as fat. Obesity can be the result of:

• Eating more food than your body can use
• Drinking too much alcohol
• Not getting enough exercise

An underactive thyroid (hypothyroidism) may lead to weight gain, but usually only 5 - 10 pounds of weight. Some antidepressants and antipsychotic medicines may also contribute to weight gain and obesity. Genetic factors play some part in the development of obesity -- children of obese parents are 10 times more likely to be obese than children with parents of normal weight.

People who are at higher risk for obesity include:

• Lower income groups
• Former smokers
• People with chronic mental illness
• People with disabilities
• People with a sedentary lifestyle

Signs and tests

The health care provider will perform a physical exam and ask questions about your medical history, eating habits, and exercise routine.

Skin fold measurements may be taken to check your body fat percentage.

Blood tests may be done to look for thyroid or endocrine problems, which could lead to weight gain.

Treatment

DIET

A combination of dieting and exercise (when you stick to it) appears to work better than either one alone. Sticking to a weight reduction program is difficult and requires a lot of support from family and friends.

When dieting, your main goal should be to learn new, healthy ways of eating and make them a part of your everyday routine. Work with your doctor and nutritionist to set realistic, safe daily calorie counts that assure both weight loss and good nutrition. Remember that if you drop pounds slowly and steadily, you are more likely to keep them off. Your nutritionist can teach you about healthy food choices, appropriate portion sizes, and new ways to prepare food.

Even modest weight loss can improve your health. Most people can lose weight by eating a healthier diet, exercising more, and adopting new behaviors such as keeping a food diary, avoiding food triggers, and thinking positively.

The decision to keep fit requires a lifelong commitment of time and effort. Patience is essential.

See also: Sweeteners

Several simple behavioral changes can have an impact on your weight loss success:

• Eat only at the table. No snacking in front of the TV, in bed, while driving, or while standing in front of the open refrigerator.
• Learn about appropriate portion sizes.
• Choose low-calorie snacks, such as raw vegetables.
• Consider learning meditation or yoga as a way of managing stress, rather than snacking.
• Find ways to socialize and enjoy your friends and family that don't involve a meal or dessert.
• Consider keeping a diet and exercise journal. This may help you identify overeating triggers in your life.
• Find a support group or consider psychotherapy to help support you in the difficult but worthy goal of weight loss.

EXERCISE

Exercise is a major mood lifter, a great way to burn energy, and a way to strengthen your bones. Exercise can also help you manage high blood pressure, heart disease, or diabetes.

Avoid a sedentary lifestyle by increasing your activity level.

• Perform aerobic exercise for at least 30 minutes a day, three times a week.
• Increase your physical activity by walking, rather than driving.
• Climb stairs instead of using an elevator or escalator.
• Always talk to your health care provider before starting an exercise program.

MEDICATIONS AND HERBAL REMEDIES

There are many over-the-counter diet products. Most do not work and some can be dangerous. Before using one of these products, talk to your health care provider.

Several prescription weight loss drugs are available. Such medicines include subutramine (Meridia) and orlistat (Xenical). Ask your health care provider if these are right for you.

Usually, you can lose between 5 and 10 pounds by taking these drugs. People usually regain the weight when they stop taking the medication, unless they have made lasting lifestyle changes.

SURGERY

Weight-loss surgery may be an option if you are very obese and have not been able to lose weight through diet and exercise. However, these surgeries are not a "quick fix" for obesity. You must still be committed to diet and exercise after the surgery.Talk to your doctor to learn if this is a good option for you.

The two most common weight-loss surgeries are:

• Laparoscopic gastric banding -- the surgeon places a band around the upper part of your stomach, creating a small pouch to hold food. The band limits the amount of food you can eat by making you feel full after eating small amounts of food.
• Gastric bypass surgery -- helps you lose weight by changing how your stomach and small intestine handle the food you eat. After the surgery, you will not be able to eat as much as before, and your body will not absorb all the calories and other nutrients from the food you eat.

Support Groups

Many people find it easier to follow a diet and exercise program if they join a group of people with similar problems.

See: Eating disorders - support group

Complications

Obesity is a significant health threat. The extra weight puts added stress on all parts of your body.

Medical problems commonly resulting from untreated obesity and morbid obesity include:

• Type 2 diabetes and metabolic syndrome
• High blood pressure, heart disease, and stroke
• Obstructive sleep apnea and other sleep disorders
• Certain cancers, including breast and colon
• Depression
• Osteoarthritis

Extreme obesity can lead to a gradual decrease in the level of oxygen in your blood, a condition called hypoxemia. Decreased blood oxygen levels and sleep apnea may cause a person to feel sleepy during the day. These conditions may also lead to high blood pressure and pulmonary hypertension. In extreme cases, especially when left untreated, this can lead to right-sided heart failure and ultimately death.

Calling your health care provider

Schedule an appointment with your health care provider if you or your child are obese or gaining weight at an extremely rapid rate. Remember that catching the problem early is much simpler than trying to fix it after the person has gained an excessive amount of weight.

References

Leslie D, Kellogg TA, Ikramuddin S. Bariatric surgery primer for the internist: keys to the surgical consultation. Med Clin North Am. 2007;91:353-381.

Richards WO, Schirmer BD. Morbid Obesity. In: Townsend CM Jr., Beauchamp RD, Evers BM, Mattox KL, eds. Sabiston Textbook of Surgery. 18th ed. Philadelphia, Pa: Saunders Elsevier;2007:chap 17.

Gardner CD, Kiazand A, Alhassan S, et al. Comparison of the Atkins, Zone, Ornish, and LEARN diets for change in weight and related risk factors among overweight premenopausal women: the A TO Z Weight Loss Study: a randomized trial. JAMA. 2007;297(9): 969-977.

Hughes AR, Stewart L, Chapple J, et al. Randomized, controlled trial of a best-practice individualized behavioral program for treatment of childhood overweight: Scottish Childhood Overweight Treatment Trial (SCOTT). Pediatrics. 2008;121(3):e539-546.

Thompson WG, Cook DA, Clark MM, et al. Treatment of obesity. Mayo Clin Proc. 2007;82(1):93-101

Svetke, LP, Stevens VJ, Brantley PJ, et al. Comparison of strategies for sustaining weight loss: the weight loss maintenance randomized controlled trial. JAMA. 2008;299(10):1139-48.

Kaplan LM, Klein S, Boden G, Brenner DA, Gostout CJ, Lavine JE, Popkin BM, Schirmer BD, Seeley RJ, Yanovski SZ, Cominelli F. Report of the American Gastroenterological Association (AGA) Institute Obesity Task Force. Gastroenterology. 2007;132(6):2272-5.