It could affect your food choices later.

It turns out what you eat during the work day may matter more than you think: A new study in the American Journal of Preventive Medicine finds that eating junk food and other unhealthy options at lunch can actually worsen the food choices you're likely to make later in the day. And those who eat "bad" lunches are more likely to be obese.

The study followed more than 600 employees at Massachusetts General Hospital in Boston. The employees participated in a work-sponsored healthy-eating campaign in which the hospital used color-coded labels on the food served at its five on-site cafeterias to indicate the food's healthfulness: Green stood for healthy, yellow stood for less healthy and red stood for unhealthy.

In addition to labeling food in easy-to-identify ways, the hospital also put the least healthy food options the farthest out of reach, to encourage the employees to make better choices.

The researchers tracked employees' purchases through their employee badges, and then analyzes them alongside the participants' overall diet as well as measured the participants' levels of obesity, diabetes, blood pressure, and cholesterol, among other factors.

They found that the employees who made the least healthy purchases also had the lowest overall dietary quality-i.e., they also didn't eat well outside of work-and had the highest risk for obesity, diabetes, and high blood pressure. On the flip side, those who made healthy purchases at work were more likely to eat healthfully outside of work, the researchers say, and had the lowest prevalence of obesity, hypertension, and prediabetes and diabetes.

While it may seem obvious-making poor dietary choices at work would indicate a likelihood of making poor dietary choices at home-the researchers were hopeful that addressing one may improve the other, writing, "These results suggest that improving the healthfulness of worksite food choices could improve dietary quality, reduce cardiometabolic risk factors, and slow or prevent weight gain."

It's important to know that, while finding a correlation between lunch choices and obesity, the study doesn't show causation. In other words, it's unclear whether people who make unhealthy food choices make those same choices outside of work because they ate poorly at work-or simply that these people are inclined to eat unhealthy options wherever they are.

One thing does seem clear, however: Making good decisions anywhere can help fight weight gain and other negative impacts of unhealthy eating, such as hypertension and diabetes.

And the researchers think more workplaces should help employees start making better decisions in the lunch cafeteria.

"Employer-sponsored programs to promote healthy eating could reach millions of Americans and help to curb obesity, a worsening epidemic that too often leads to diabetes, cardiovascular disease, and cancer," lead investigator Anne N. Thorndike, M.D., M.P.H. says.

But if your workplace isn't offering anything more than a vending machine, you can still make healthy decisions during the day by packing healthy snacks and a healthful lunch. Here are cheap and healthy lunch ideas for work, and the 10 best snacks for weight loss.

Person Eating a Sandwich
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