The study used data from a U.S. Department of Agriculture survey, focusing on purchases made by more than 5,000 employees from vending machines or cafeterias, as well as food available in the workplace for free.
Results suggest food purchased by employees tend to have lots of solid fats and/or added sugars. The food people get at work also tend to have high amounts of sodium and refined grains.
The study found that of the average 1,300 calories obtained weekly in workplace food, more than 70% came from free food.
"Since we found that a lot of the foods obtained by employees were free, employers may also want to consider healthy meeting policies to encourage healthy food options at meetings and social events," said Stephen Onufrak, an epidemiologist in the Division of Nutrition, Physical Activity, and Obesity at the Centers for Disease Control and Prevention, in a statement.
Results were presented at the American Society for Nutrition's annual meeting in Boston.
Researchers are now conducting a similar study focused more deeply on foods purchased at vending machines or cafeterias. They advise workplaces to offer more wellness programs to encourage healthier eating.
"We hope that the results of our research will help increase healthy food options at worksites in the U.S.," Onufrak said.