New research finds people eat more when a food is branded as "fit."

By Grace Elkus
Updated June 24, 2015
Joe Biafore/Getty Images

In an effort to attract physically active and heath-conscious consumers, some food brands use fitness-focused packaging (think: a runner emblazoned on the front of an energy bar). But instead of motivating consumers to get active, this “fitness branding” might actually undermine weight loss efforts, according to a new study published in the Journal of Marketing Research.

The authors, from the Pennsylvania State University and Technische Universität München (a research university in Munich), explored the effects this type of branding can have by studying diet and exercise habits in “restrained” eaters, or people who are chronically concerned about their body weight. They found that labeling a food as "fit" caused these eaters to consume more, unless the food was forbidden by their diet. “To make matters worse, these eaters also reduced their physical activity, apparently seeing the ‘fit’ food as a substitute for exercise,” wrote the authors.

The study was three-fold and involved more than 500 male and female participants. In the first phase, participants were told to pretend they were at home helping themselves to an afternoon snack. They were given snacks either labeled “Fitness” with a pair of running shoes pictured, or “Trail Mix.” They then had eight minutes to taste and rate the product, recording their thoughts in a 33-part questionnaire. In phase two, trail mix was promoted as healthy to one group and described as "dietary forbidden" to a second. In the third phase, participants were given the option to exercise on a stationary bike after eating the snack.

Not only did participants eat more of the snack labeled “Fitness,” but they also expended less energy after consuming it—presumably because they felt they didn't need to work out as vigorously.

The takeaway? While fitness-focused foods aren't necessarily bad, per se, they shouldn't be seen as a substitute for exercise. Pay attention to ingredient lists as well—because even so-called "healthy" foods can secretly sabotage your diet.