Marriage keeps you healthy, even though it can make men fat, U.S. government researchers said on Wednesday.

Married people are less likely to smoke, drink heavily or be physically inactive, the report from the National Center for Health Statistics shows.

They are less likely than singles, divorcees or widowed adults to be in fair or poor health, and are less likely to suffer from headaches or serious psychological distress.

But the report finds that married men are more likely to be overweight or obese than other men. “Never-married adults were among the least likely to be overweight or obese,” the report reads.

Health statistician Charlotte Schoenborn, who led the study, said more research is needed to understand just why, for instance, married men weigh more. “One can speculate based on one’s impression of humanity but we don’t have any data to back it up,” she said in a telephone interview.

“For the smoking rates between married and unmarried people, the differences were quite remarkable,” she added.

“One in five married adults were current smokers compared to four in 10 of those living with a partner. Married people are about half as likely to be current smokers as those who are divorced or living with a partner.”

The report from the National Center for Health Statistics, part of the Centers for Disease Control and Prevention, was based on interviews with 127,545 adults aged 18 and over.

It finds that 58.2 percent of adults are married, 10.4 percent are separated or divorced, 6.6 percent are widowed, 19 percent never married and 5.7 percent are living with a partner.

About 61 percent of whites, 58 percent of Hispanics and 38 percent of blacks are married, it found.

People living together but not married are more likely to have health problems than married adults, the survey found, and the findings hold firmest for the youngest adults.

The report, which can be found in the Internet at http:/www.cdc.gov/nchs, is in line with many other studies that show married people tend to be healthier. There are two major theories as to why, said the researchers.

“Marriage protection is the theory that married people have more advantages in terms of economic resources, social and psychological support, and support for healthy lifestyles,’ the report says.

“Marital selection is the theory that healthier people get married and stay married, whereas less-healthy people either do not marry or are more likely to become separated, divorced, or widowed.”

Schoenborn, who has been following U.S. health statistics for more than 20 years, said she was interested to find out if the “marriage effect” on health had changed as society’s view of single and divorced people changed.

“I was looking to find out where things are currently, but I wouldn’t say I was surprised. My personal impression is that marriage probably offers a level of stability,” Schoenborn said.