Obesity is a complex disorder involving an excessive amount of body fat. Obesity isn't just a cosmetic concern. It increases your risk of diseases and health problems, such as heart disease, diabetes and high blood pressure. Being extremely obese means you are especially likely to have health problems related to your weight.
For adults 35 and older, having a BMI greater than 30 is considered obese. The body mass index is calculated using a person's height and weight. The body mass index (BMI) equals a person's weight in kilograms (kg) divided by their height in meters (m) squared. Since BMI describes body weight relative to height, it is strongly correlated with total body fat content in adults. An adult who has a BMI of 25-29.9 is considered overweight, and an adult who has a BMI over 30 is considered obese. A BMI of 18.5-24.9 is considered normal weight.
Even though medications and diets can help, the treatment of obesity cannot be a short-term "fix" but has to be a lifelong commitment to proper diet habits, increased physical activity, and regular exercise. Obesity is difficult to treat and has a high relapse rate. Most people who lose weight regain the weight within five years. For patients with a BMI over 40, life expectancy is reduced significantly.
Obesity also increases the risk of developing a number of chronic diseases, including the following:
Insulin resistance. Insulin is necessary for the transport of blood glucose (sugar) into the cells of muscle and fat (which is then used for energy). By transporting glucose into cells, insulin keeps the blood glucose levels in the normal range. Insulin resistance (IR) is the condition whereby the effectiveness of insulin in transporting glucose (sugar) into cells is diminished. Fat cells are more insulin resistant than muscle cells; therefore, one important cause of insulin resistance is obesity. The pancreas initially responds to insulin resistance by producing more insulin. As long as the pancreas can produce enough insulin to overcome this resistance, blood glucose levels remain normal. This insulin resistance state (characterized by normal blood glucose levels and high insulin levels) can last for years. Once the pancreas can no longer keep up with producing high levels of insulin, blood glucose levels begin to rise, resulting in type 2 diabetes, thus insulin resistance is a pre-diabetes condition.
Type 2 (adult-onset) diabetes. The risk of type 2 diabetes increases with the degree and duration of obesity. Type 2 diabetes is associated with central obesity; a person with central obesity has excess fat around his/her waist, so that the body is shaped like an apple.
High blood pressure (hypertension). Hypertension is common among obese adults. A Norwegian study showed that weight gain tended to increase blood pressure in women more significantly than in men.
High cholesterol (hypercholesterolemia)
Stroke (cerebrovascular accident or CVA)
Heart attack. A prospective study found that the risk of developing coronary artery disease increased three to four times in women who had a BMI greater than 29. A Finnish study showed that for every 1 kilogram (2.2 pounds) increase in body weight, the risk of death from coronary artery disease increased by 1%. In patients who have already had a heart attack, obesity is associated with an increased likelihood of a second heart attack.
Congestive heart failure
Cancer. Obesity has been linked to cancer of the colon in men and women, cancer of the rectum and prostate in men, and cancer of the gallbladder and uterus in women. Obesity may also be associated with breast cancer, particularly in postmenopausal women. Fat tissue is important in the production of estrogen, and prolonged exposure to high levels of estrogen increases the risk of breast cancer.
Gout and gouty arthritis
Osteoarthritis (degenerative arthritis) of the knees, hips, and the lower back
What causes obesity?The balance between calorie intake and energy expenditure determines a person's weight. If a person eats more calories than he or she burns (metabolizes), the person gains weight (the body will store the excess energy as fat). If a person eats fewer calories than he or she metabolizes, he or she will lose weight. Therefore the most common causes of obesity are overeating and physical inactivity. Ultimately, body weight is the result of genetics, metabolism, environment, behavior, and culture.
Genetics. A person is more likely to develop obesity if one or both parents are obese. Genetics also affect hormones involved in fat regulation. For example, one genetic cause of obesity is leptin deficiency. Leptin is a hormone produced in fat cells and also in the placenta. Leptin controls weight by signaling the brain to eat less when body fat stores are too high. If, for some reason, the body cannot produce enough leptin or leptin cannot signal the brain to eat less, this control is lost, and obesity occurs. The role of leptin replacement as a treatment for obesity is currently being explored.
Overeating. Overeating leads to weight gain, especially if the diet is high in fat. Foods high in fat or sugar (for example, fast food, fried food, and sweets) have high energy density (foods that have a lot of calories in a small amount of food). Epidemiologic studies have shown that diets high in fat contribute to weight gain.
A diet high in simple carbohydrates. The role of carbohydrates in weight gain is not clear. Carbohydrates increase blood glucose levels, which in turn stimulate insulin release by the pancreas, and insulin promotes the growth of fat tissue and can cause weight gain. Some scientists believe that simple carbohydrates (sugars, fructose, desserts, soft drinks, beer, wine, etc.) contribute to weight gain because they are more rapidly absorbed into the bloodstream than complex carbohydrates (pasta, brown rice, grains, vegetables, raw fruits, etc.) and thus cause a more pronounced insulin release after meals than complex carbohydrates. This higher insulin release, some scientists believe, contributes to weight gain.
Frequency of eating. The relationship between frequency of eating (how often you eat) and weight is somewhat controversial. There are many reports of overweight people eating less often than people with normal weight. Scientists have observed that people who eat small meals four or five times daily, have lower cholesterol levels and lower and/or more stable blood sugar levels than people who eat less frequently (two or three large meals daily). One possible explanation is that small frequent meals produce stable insulin levels, whereas large meals cause large spikes of insulin after meals.
Physical inactivity. Sedentary people burn fewer calories than people who are active. The National Health and Nutrition Examination Survey (NHANES) showed that physical inactivity was strongly correlated with weight gain in both sexes.
Medications. Medications associated with weight gain include certain antidepressants (medications used in treating depression), anticonvulsants (medications used in controlling seizures such as carbamazepine [Tegretol, Tegretol XR , Equetro, Carbatrol] and valproate [Depacon, Depakene]), some diabetes medications (medications used in lowering blood sugar such as insulin, sulfonylureas, and thiazolidinediones), certain hormones such as oral contraceptives, and most corticosteroids such as prednisone. Weight gain may also be seen with some high blood pressure medications and antihistamines. The reason for the weight gain with the medications differs for each medication. If this is a concern for you, you should discuss your medications with your physician rather than discontinuing the medication, as this could have serious effects.
Psychological factors. For some people, emotions influence eating habits. Many people eat excessively in response to emotions such as boredom, sadness, stress, or anger. While most overweight people have no more psychological disturbances than normal weight people, about 30% of the people who seek treatment for serious weight problems have difficulties with binge eating.
Diseases such as hypothyroidism, insulin resistance, polycystic ovary syndrome, and Cushing's syndrome are also contributors to obesity.
Social issues: A link between social issues and obesity has been established. Lack of money to purchase healthy foods or lack of safe places to walk or exercise can increase the risk of obesity
What is the role of physical activity and exercise in obesity?
The National Health and Examination Survey (NHANES I) showed that people who engage in limited recreational activity were more likely to gain weight than more active people. Other studies have shown that people who engage in regular strenuous activity gain less weight than sedentary people.
Physical activity and exercise help burn calories. The amount of calories burned depends on the type, duration, and intensity of the activity. It also depends on the weight of the person. A 200-pound person will burn more calories running 1 mile than a 120-pound person, because the work of carrying those extra 80 pounds must be factored in. But exercise as a treatment for obesity is most effective when combined with a diet and weight-loss program. Exercise alone without dietary changes will have a limited effect on weight because one has to exercise a lot to simply lose 1 pound. However regular exercise is an important part of a healthy lifestyle to maintain a healthy weight for the long term. Another advantage of regular exercise as part of a weight-loss program is a greater loss of body fat versus lean muscle compared to those who diet alone.
Other benefits of exercise include
- Improved blood sugar control and increased insulin sensitivity (decreased insulin resistance),
- Reduced triglyceride levels and increased "good" HDL cholesterol levels,
- Lowered blood pressure,
- Reduction in abdominal fat,
- Reduced risk of heart disease,
- Release of endorphins that make people feel good.
- Remember, these health benefits can occur independently (with or without) achieving weight loss. Before starting an exercise program, talk to a doctor about the type and intensity of the exercise program.
General exercise recommendations
- Perform 20-30 minutes of moderate exercise five to seven days a week, preferably daily. Types of exercise include stationary bicycling, walking or jogging on a treadmill, stair climbing machines, jogging, and swimming.
- Exercise can be broken up into smaller 10-minute sessions.
- Start slowly and progress gradually to avoid injury, excessive soreness, or fatigue. Over time, build up to 30-60 minutes of moderate to vigorous exercise every day.
- People are never too old to start exercising. Even frail, elderly individuals (70-90 years of age) can improve their strength and balance.
- Exercise precautions
The following people should consult a doctor before vigorous exercise:
Men over age 40 or women over age 50
Individuals with heart or lung disease, asthma, arthritis, or osteoporosis
Individuals who experience chest pressure or pain with exertion, or who develop fatigue or shortness of breath easily
Individuals with conditions or lifestyle factors that increase their risk of developing coronary heart disease, such as high blood pressure, diabetes, cigarette smoking, high blood cholesterol, or having family members with early onset heart attacks and coronary heart disease
A patient who is obese
General diet guidelines for achieving and (just as importantly) maintaining a healthy weight
A safe and effective long-term weight reduction and maintenance diet has to contain balanced, nutritious foods to avoid vitamin deficiencies and other diseases of malnutrition.
Eat more nutritious foods that have "low energy density." Low energy dense foods contain relatively few calories per unit weight (fewer calories in a large amount of food). Examples of low energy dense foods include vegetables, fruits, lean meat, fish, grains, and beans. For example, you can eat a large volume of celery or carrots without taking in many calories.
Eat less "energy dense foods." Energy dense foods are high in fats and simple sugars. They generally have a high calorie value in a small amount of food. The United States government currently recommends that a healthy diet should have less than 30% fat. Fat contains twice as many calories per unit weight than protein or carbohydrates. Examples of high-energy dense foods include red meat, egg yolks, fried foods, high fat/sugar fast foods, sweets, pastries, butter, and high-fat salad dressings. Also cut down on foods that provide calories but very little nutrition, such as alcohol, non-diet soft drinks, and many packaged high-calorie snack foods.
About 55% of calories in the diet should be from complex carbohydrates. Eat more complex carbohydrates such as brown rice, whole-grain bread, fruits, and vegetables. Avoid simple carbohydrates such as table sugars, sweets, doughnuts, cakes, and muffins. Cut down on non-diet soft drinks, these sugary soft drinks are loaded with simple carbohydrates and calories. Simple carbohydrates cause excessive insulin release by the pancreas, and insulin promotes growth of fat tissue.
Educate yourself in reading food labels and estimating calories and serving sizes.
Consult a doctor before starting any dietary changes. You doctor or a nutritionist should prescribe the amount of daily calories in your diet.
What is the role of medication in the treatment of obesity?
Medication treatment of obesity should be used only in patients who have health risks related to obesity. Medications should be used in patients with a BMI greater than 30 or in those with a BMI of greater than 27 who have other medical conditions (such as high blood pressure, diabetes, high blood cholesterol) that put them at risk for developing heart disease. Medications should not be used for cosmetic reasons.
Medications should only be used as an adjunct to diet modifications and an exercise program.
Like diet and exercise, the goal of medication treatment has to be realistic. With successful medication treatment, one can expect an initial weight loss of at least 5 pounds during the first month of treatment, and a total weight loss of 10%-15% of the initial body weight. It is also important to remember that these medications only work when they are taken. When they are discontinued, weight gain often occurs.