Lead study author Zhou Yang of the University of Florida said he found an elderly person who is overweight at 65 may spend $16,000 more -- and the obese person may spend $26,000 more -- than those who are a normal weight at age 65.

The study, published in the online issue of the journal Health Services Research, said 35 percent of U.S. adults are overweight and another 30 percent are obese -- and the total extra cost of treating them could jump to hundreds of billions of dollars as they age.

Life expectancy for a man of normal weight is 76.1 years; for an overweight man it’s 75.9 and for an obese man, it’s 74.2. For a woman of normal weight, life expectancy is 74 years; for an overweight woman it’s 72.7 and for an obese woman it’s 71.6, the study said.

"We must do a better job of informing the general public about the health risks associated with obesity and promote a healthy lifestyle," Yang said in a statement.