Who becomes obese or overwight?

The World Health Organization now considers obesity to be a global epidemic and a public health problem as more nations become "Westernized." Globally, an estimated 250 million adults are now obese, and many more are overweight.

Obesity in American Adults

The prevalence of obesity (defined as a BMI of over 30) in the United States has risen dramatically over the past few years. It is now estimated that 61% of Americans are now overweight, up from 43% in the early 1940s. And according to a 2001 study, nearly 20% of American adults are obese (BMI over 30). Regionally, the prevalence of obesity is lowest in the Western states (13.8% in Colorado) and highest in the South (24% in Mississippi).

Gaining some weight is inevitable with age and adding about 10 pounds to a normal base weight over time is not harmful. The weight gain in American adults over 50, however, is significant, with 64% of women and 73% of men being seriously overweight. This condition is made worse by the fact that muscle and bone mass decrease with age, so the fat increase is actually about one and a half pounds. Some studies suggest that by age 55, the average American has added over 37 pounds of fat during the course of adulthood.

Obesity by Ethnic, Social, and Income Groups

Obesity is more prevalent in lower economic groups but it appears to be increasing in young adults with some college education. Obesity, in fact, has increased in every state, in both men and women, across all age groups, and in every ethnic group. Among ethnic groups, African American women are more overweight than Caucasian women but African American men are less obese than Caucasian men. Hispanic men and women tend to weigh more than Caucasians.

Weight Gain by Gender

In men, BMI tends to increase until age 50 and then it levels off; in women, weight tends to increase until age 70 before it plateaus. A 2000 study has found that there are three high-risk periods for weight gain in women.

• The first is at the onset of menstruation, particularly if it is early. (It should also be noted, that obesity in childhood may actually be a contributor to early puberty, which in turn increases the risk for more weight gain.)
• The second is after pregnancy, with higher risk for women who are already overweight.
• Finally, many women tend to gain weight after menopause.

These findings are significant because they may allow women to target high-risk times, and consequently prevent unnecessary weight gain.

Obesity in Children

More children and adolescents are overweight in America than ever before. According to a 2001 report based on a study of 8,000 children, the rate of overweight children among African-American and Hispanics increased by more than 120% and among Caucasian children by 50% between 1986 and 1998. In the study, 22% of African-American and Hispanic children were overweight, while about 12% of Caucasian children were overweight. Other studies have estimated that about 35% of children were either at risk for being overweight or are overweight. And the problem is becoming global.