Do you eat to impress? A new study finds that sometimes people do.

What and how much we eat are determined by a multitude of factors that go well beyond physical sustenance.

Culture, religion, income level, family, cooking skills and accessibility are among them.

Social forces also play a significant role, especially when it comes to making healthier food choices. Studies have found that family, friends and co-workers all have a significant influence on the foods we choose.

And we often make inferences about the character of others based on their food choices. For example, people who eat “healthy” foods generally are viewed more positively than those who don’t.

Now, a study involving Northwestern University researchers has found that eating with people in different social groups, especially those outside of your social circle, also can influence healthy food choices.

The study, involving researchers from Oxford University, the Bayes Business School in London and Northwestern’s Kellogg School of Management found that people will choose healthier food options in the presence of outsiders to make a good impression and reduce anticipated negative judgment.

The study included four experiments and was based in a large American city and university and included 1,000 adults. The researchers looked at how different racial groups, university affiliations and workplace affiliation impacted participants’ food choices.

The first two parts of the research looked at food choices based on in-group versus influences outside of the group. Nearly 200 college students were given a choice of M&M’s or raisins. When in the presence of an unknown fellow student from one’s own university, only 12% of students selected the healthier raisins. This more than doubled, to 31%, when in the presence of an unknown student from another university.

The other two parts of the research sought to shed light on why this is the case and concluded it’s because of a fear of being negatively judged by outsiders.

The researchers found that, when people anticipate they might be negatively judged by outside groups, they might strategically make seemingly healthier food choices to counter this negativity and create a more positive impression.

This was demonstrated when a group of 200 people were told that others around them were either judgmental or tolerant. In the judgmental environment, subjects were more likely to choose carrots over cookies than in the tolerant environment.

Environmental Nutrition is an independent newsletter written by nutrition experts.