It seems that not a week goes by without a report from somewhere around the world stating that obesity is becoming a bigger epidemic. Obesity claims nearly 300,000 lives per year, health officials say. In fact more than one-third of U.S. adults (35.7%) are obese. And today, about one in three American kids and teens are overweight or obese; nearly triple the rate in 1963. An estimated $117 billion in direct (preventive, diagnostic, and treatment services related to weight) and indirect (absenteeism, loss of future earnings due to premature death) costs are attributed to obesity. This exceeds healthcare costs associated with smoking or problem drinking and accounts for 6 percent to 12 percent of national health care expenditures in the United States. Obesity is an excess proportion of total body fat. A person is considered obese when his or her weight is 20 percent or more above normal weight. The most common measure of obesity is the body mass index, or BMI. A person is considered overweight if his or her BMI is between 25 and 29.9; a person is considered obese if his or her BMI is over 30. Obesity occurs when a person consumes more calories than he or she burns. For many people, this comes down to eating too much and exercising too little, or not at all.
But there are other factors that play a role in obesity. These may include: age, gender, genetics, environment, physical activity, psychological factors, illness, and/or medication. As a person gets older, their body's ability to metabolize food slows down and they do not require as many calories to maintain their weight. This is why people note that they eat the same and do the same activities as they did when they were 20 years old, but at age 40, gain weight. Women tend to be more overweight than men. Men have a higher resting metabolic rate (meaning they burn more energy at rest) than women, so men require more calories to maintain their body weight. Also, when women become postmenopausal, their metabolic rate decrease, which is why many women gain weight after menopause. Obesity tends to run in families. In a study of adults who were adopted as children, researchers found that participating adult weights were closer to their biological parents' weights than their adoptive parents. The environment provided by the adoptive family apparently had less influence on the development of obesity than the person's genetic makeup. In fact, if your biological mother is heavy as an adult, there is approximately a 75 percent chance that you will be heavy. If your biological mother is thin, there is also a 75 percent chance that you will be thin. Nevertheless, people who feel that their genes have doomed them to a lifetime of obesity should take heart. Many people genetically predisposed to obesity do not become obese or are able to lose weight and keep it off. Although genes are an important factor in many cases of obesity, a person's environment can play a significant role. Environmental factors include lifestyle behaviors such as what a person eats and how active he or she is. Active individuals require more calories than less active ones to maintain their weight. Additionally, physical activity tends to decrease appetite in obese individuals while increasing the body's ability to preferentially metabolize fat as an energy source. Much of the increase in obesity in the last 20 years is thought to have resulted from the decreased level of daily physical activity. Psychological factors also influence eating habits and obesity. Many people eat in response to negative emotions such as boredom, sadness, or anger. People who have difficulty with weight management may be facing more emotional and psychological issues; about 30 percent of people who seek treatment for serious weight problems have difficulties with binge eating. During a binge-eating episode, people eat large amounts of food while feeling they can't control how much they are eating. Although not