Stress causes people to gain weight, but only if they’re overweight to begin with, according to a Harvard University Study published in the American Journal of Epidemiology.

To reach this conclusion, Jason Block and colleagues followed a nationally representative cohort of 1,355 US men and women for 9 years.

They examined the relation between body mass index changes and multiple domains of psychosocial stress including those related to finances, work, life constraints and personal relationships.

The scientists controlled for other factors known to be associated with weight gain.

For people who had normal BMI at study onset, there was no relationship between stress and weight gain.

Overweight men packed on additional pounds when exposed to stress associated with a lack of decision authority at work, a perceived inability to learn new skills on the job and to carry out fulfilling job responsibilities, as well as personal financial difficulties.

Overweight women also gained weight when encountering job-related and financial stress, but unlike men, also gained weight when confronted by perceived constraints in home life and strained family relations. 

“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,” Block told BurrillReport.

The scientists posit that individuals change their eating behaviors when they are under stress, and that precipitates weight gain. As a result, they recommend that stress reduction should become part of workplace-related weight-loss programs as well as various public health programs.

“Our findings show that stress should be recognized as a threat to the well-being of American adults, especially those who are already overweight,” Block concluded.