Pushing the U.S. obesity rate down to 1987 levels by 2027 could cut per-capita health care spending 4% that year, according to the Congressional Budget Office.

CBO researchers make that suggestion in a brief on the effects of obesity on health care spending.

The percentage of U.S. adults who are overweight or obese increased to 63% in 2007, from 44% in 1987, researchers report.

Some scientists have speculated that the increase in obesity rates might be partly related to factors such as food additives or viruses, or to a decline in physical activity.

The CBO researchers cite an early study suggesting that the weight shift is “related mostly to an increase in caloric intake–and, in particular, an increase in calories from snacks–rather than to a decline in physical activity.”

The percentage of U.S. health care spending that appears to be the result of excess weight increased to 32% in 2007, from 18% in 1985, the researchers report.

If the country could reduce the percentage of adults who are obese to 20% in 2027, the inflation-adjusted increase in per-capital health care spending would be about $270 less than if the population weight distribution remains the same, and $530 per person less than if obesity rates continue to increase, the researchers say.

But, if falling obesity rates made Americans healthier, they might live longer, and that could increase the cost of Social Security and other retirement programs, researchers say.

Thinner, healthier Americans might spend more on health care on their extra years of life, the researchers add.

“As a result, the net impact of reductions in obesity rates on national health care expenditures and on federal budget deficits would depend on the magnitude of those various effects,” the researchers say.

-ab