Obesity simply means an accumulation of body fat.
To calculate your Body Mass Index, go to our Body Mass Index Calculator. Causes of Obesity in Adulthood Obesity in the United States is on the rise. In the United States, obesity is twice as common among women in lower socioeconomic groups that in higher ones. Why this occurs is not fully understood, however, women in higher socioeconomic groups tend to have more time and resources for dieting and exercise. Obese people, particularly those who have been obese since childhood, may have five times more fat cells that people with normal weight.