Being stressed out can cause people to pack on the pounds, with women’s weight more affected by life’s anxieties than men, according to Harvard University researchers. The nationally representative group of 1,355 men and women who were followed for more than nine years gained more weight while experiencing increased psychological stress if they already had higher body mass indexes. A similar weight-gain pattern was not found among lower-weight people who were dealing with the same types of stress, according to the study in the American Journal of Epidemiology.

The researchers say the study is believed to be one of the first of its kind to look at the relationship between weight gain and multiple types of stress in the U.S. population. The stress included job-related demands, difficulty paying bills, strained family relationships, depression or anxiety disorder.

"Today's economy is stressing people out, and stress has been linked to a number of illnesses—such as heart disease, high blood pressure and increased risk for cancer,” says Jason Block, who conducted the research as a Robert Wood Johnson Foundation Health & Society Scholar at Harvard University.

Researchers say women's waistlines are affected by more types of stress. In addition to weight gain associated with financial problems or a difficult job, women also gained weight when grappling with strained family relationships and feeling limited by life's circumstances, researchers say.

For men, they did not gain weight when facing difficult family relationships or feeling constrained by life circumstances, researcher say. Among men, lack of decision authority at work and lack of skill discretion—the ability to learn new skills on the job and to perform interesting job duties—was associated with greater weight gain.

The researchers say that individuals may change their eating behaviors when stressed out, leading to changes in weight. Stress-induced weight gain is influenced by a person's gender, what types of foods people eat when they change their eating behaviors, and whether the person is already overweight or obese, they say.

The researchers add that stress reduction may be an important part of weight-loss programs in the workplace and in clinical and public health programs. In the workplace, access to weight-loss programs, flexible work schedules, and exercise programs can help stressed-out workers, they say.

"This is one of the first studies to explore the relationship between stress and weight gain in a U.S. population," Block says. "Our findings show that stress should be recognized as a threat to the well-being of American adults, especially those who are already overweight."