Reasons for the growth in girth are debated
Obesity means having excess body fat. For adults 35 and older, having a BMI greater than 30 is considered obese.
Obesity is Common, Serious and Costly
More than one-third of U.S. adults (35.7 percent) are obese. It has reached epidemic proportions in this country has has been increasing worldwide for the past 20 years.
Obesity-related conditions include heart disease, stroke, type 2 diabetes, sleep apnea, high blood pressure, osteoarthritis and certain types of cancer, some of the leading causes of preventable death. About 300,000 deaths per year are directly related to obesity, and more than 80 percent of these deaths are in patients with a BMI higher than 30. For patients with a BMI greater than 40, life expectancy is reduced significantly (as much as 20 years for men and five years for women).
In 2008, medical costs associated with obesity were estimated at $147 billion; the medical costs for people who are obese were $1,429 higher than those of normal weight.
Obesity Affects Some Groups More Than Others
Black folks have the highest age-adjusted rates of obesity (49.5 percent) compared with Mexican Americans (40.4 percent), all Hispanics (39.1 percent) and non-Hispanic whites (34.3 percent). African-American women have the highest rates overweight and obesity compared to other groups in the U.S. About 4 in 5 African-American women are overweight or obese.
Obesity and Socioeconomic Status
Among non-Hispanic black and Mexican-American men, those with higher incomes are more likely to be obese than those with low income.
Higher-income women are less likely to be obese than low-income women.
There is no significant relationship between obesity and education among men. Among women, however, there is a trend—those with college degrees are less likely to be obese compared with less educated women.
Between 1988-1994 and 2007-2008 the prevalence of obesity increased in adults at all income and education levels.
What Causes Obesity?
Put simply: If a person eats more calories than he or she burns, the person gains weight (the body stores the excess energy as fat). If a person eats fewer calories than he or she metabolizes, he or she will lose weight. So 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.
Overeating. Overeating leads to weight gain, especially if a person eats a high-fat diet. Foods high in fat or sugar (think: fast food, fried food and sweets) have high energy density (foods that have a lot of calories in a small amount of food). Studies show diets high in fat contribute to weight gain.
Carbohydrates. The role of carbohydrates in weight gain is less clear. Carbs increase blood glucose levels, which 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) and thus cause a more pronounced insulin release after meals than complex carbohydrates. This higher insulin release, some scientists believe, contributes to weight gain.
Slow metabolism. Women have less muscle than men. Muscle burns more calories than other tissue. As a result, women have a slower metabolism than men and have a tendency to put on more weight than men. As we age, we tend to lose muscle and our metabolism slows; therefore, we tend to gain weight as we get older, particularly if we do not reduce our daily caloric intake.
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, anticonvulsants, diabetes medications 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.
Psychological factors. Some folks eat too much in response to boredom, sadness, stress or anger.
Illness. Diseases such as hypothyroidism, insulin resistance, polycystic ovary syndrome, and Cushing’s syndrome are also contributors to obesity.
What Can Be Done About Obesity?
Too often, folks who are obese go on a strenuous diet in hopes of reaching the “ideal body weight.” Some amount of weight loss may be accomplished this way, but the lost weight usually returns. Studies show more than 95 percent of the people who lose weight regain the weight within five years.
We need to learn more about the causes of obesity, and then we need to change the ways we treat it. When obesity is accepted as a chronic disease, it will be treated like other chronic diseases such as diabetes and high blood pressure. Obesity treatment must acknowledge that even modest weight loss can be beneficial. For example, a modest weight loss of 5 percent to 10 percent of the initial weight, and long-term maintenance of that weight loss can bring significant health gains, including
lowered blood pressure;
reduced blood levels of cholesterol;
reduced risk of type 2 (adult-onset) diabetes (In the Nurses Health Study, women who lost 11 pounds reduced their risk of diabetes by 50 percent or more.);
decreased chance of stroke;
decreased complications of heart disease;
decreased overall mortality.
The message: Don’t seek to achieve an “ideal weight.” Instead, the goal of treatment should be to reach and hold to a healthier weight. Commit to the process of lifelong healthy living, including eating more wisely and increasing physical activity.
Sources: Centers for Disease Control and Prevention; Office on Women’s Health