CBO... From 1987 to 2007, the fraction of adults who were overweight or obese increased from 44 percent to 63 percent; almost two-thirds of the adult population now falls into one of those categories. The share of obese adults rose particularly rapidly, more than doubling from 13 percent to 28 percent. That sharp increase in the fraction of adults who are overweight or obese poses an important public health challenge. Those adults are more likely to develop serious illnesses, including coronary heart disease, diabetes, and hypertension. As a result, that trend also affects spending on health care...
...According to CBO's analysis of survey data, health care spending per adult grew substantially in all weight categories between 1987 and 2007, but the rate of growth was much more rapid among the obese (defined as those with a body-mass index greater than or equal to 30). Spending per capita for obese adults exceeded spending for adults of normal weight by about 8 percent in 1987 and by about 38 percent in 2007.
First, CBO assumed that there will be no future changes in the distribution of adults by body weight and, therefore, that the prevalence of obesity will remain at the 2007 rate of 28 percent. If so, per capita spending on health care for adults would rise by 65 percent—from $4,550 in 2007 to $7,500 in 2020,
Because lower rates of obesity are associated with better health and lower health care spending per capita, there is considerable interest in devising policies that would reduce the fraction of the population that is obese. Read more from CBO