The study, published in the journal Health Services, finds that overweight or obese elderly people will cost Medicare 6 percent to 17 percent more over a lifetime than treating an elderly person with a healthy weight.

The extra demands on the healthcare system by overweight and obese elderly amounts to Medicare's spending on average an extra $15,000 on overweight elderly individuals and an extra $26,000 on obese individuals.

"Our research provides valuable information for why the public and health policymakers need to pay attention to the financial burden of healthcare for overweight Americans besides it's being just a health issue," Zhou Yang of Emory University in Atlanta says in a statement.

"More aggressive public health campaigns or early behavioral or policy intervention to stop the obesity epidemic could be cost-effective as well as otherwise beneficial for society."

The researchers at Emory University and University of Florida used data from the longitudinal Medicare Current Beneficiary Survey from 1992 to 2001 to construct a model of the relationship between body weight and healthcare expenditures.