Years of being overweight not only contributes to health problems but also to a person’s economic woes, new research suggests.

Adults who have been overweight since high school are more likely to be unemployed or on welfare than those who gained weight gradually during their 20s and 30s, according to a study published in The American Journal of Epidemiology. People who have been persistently overweight since high school are also more likely to be single at 40 and have no more than a high school education, compared with those who have gained weight slowly over time, the study showed.

“We know a lot about the fact that obesity is associated with a lot of health problems later on,” said the lead author, Philippa J. Clarke of the Institute for Social Research at the University of Michigan. “But we tried to look at the social and economic consequences of being persistently overweight.”

The findings are based on a study of 5,000 high school graduates tracked for two decades. The researchers studied two groups: those who were overweight at age 19 and stayed overweight as adults, compared with those who had a healthy weight at graduation but gained weight over time.

Men and women who were persistently overweight from high school were also about three times as likely to have a chronic health problem like diabetes or high blood pressure by age 40. They were also 50 percent more likely to be receiving welfare or unemployment checks.

The researchers found that people with less educated parents were more likely to be overweight at a young age. But even controlling for parents’ lower socioeconomic status, the researchers found that the persistently overweight experienced more economic hardship than those who gained weight slowly over time, suggesting that weight status also can predict economic status.

Importantly, good grades in high school lowered a student’s risk for being persistently overweight as an adult, suggesting that schools present a unique opportunity for curbing lifelong weight problems.

“There is something about school attachment or getting kids to be more connected in school,” Dr. Clarke said. “It makes us think there is something about the school setting that can divert people form this high-risk weight gain category.”

The study was funded by the Robert Wood Johnson Foundation.