This One Grocery Trick Could Be Making You Gain Weight, Expert Says

Elizabeth Millard
·2 min read

Food marketing is so ubiquitous, we almost don't notice it anymore—all the ads in everything from grocery stores to magazines to billboards, and even on some gas pumps—but it turns out that it's succeeding, maybe a little too well.

A new study in the Journal of Consumer Psychology looked at how responsive people are to food marketing messages, and whether their buying habits might sync up based on weight. Turns out, that's true.

Researchers followed three groups: people with severe obesity before and after weight-loss surgery; people with obesity who weren't having surgery; and people categorized as normal weight. Each group was shown a breadth of branding and advertising messages and asked to estimate the calorie content in the foods and beverages they were being shown. (Related: The 7 Healthiest Foods to Eat Right Now).

Everyone in the study underestimated the calorie contents, but the effect was more significant in people with obesity. To delve deeper into whether this had an impact on actions, researchers asked participants to choose a portion of French fries based on different wording. For example, the amount of fries in a "mini" size were actually the same as one labeled "small."

"This is a marketing tactic that makes larger portions seem more reasonable," says lead researcher Yann Cornil, PhD, assistant professor at the University of British Columbia Sauder School of Business. "Those with obesity were more likely to follow this labeling as opposed to the actual information about quantity, and that could lead to them eating more than they'd planned."

By contrast, those in the normal-weight group were much less responsive to this marketing and tended to choose their fries portion based on actual quantity rather than labeling.

The good news, Cornil adds, is that weight loss seems to have an effect on those who are more prone to these marketing tricks. The group of participants who went through weight-loss surgery became less responsive to this marketing over time. A year after their surgery, their amount of responsiveness was about the same as those in the normal-weight group.

Keep in mind that the reasons are complex, says Cornil. For instance, people who experience weight loss have several physiological shifts—including hormonal changes and improvements to gut health—that could make them less likely to respond to food marketing. At the same time, they usually have a higher desire to change their habits and that could make them less prone to unhealthy food messaging.

Whatever the reason, it's helpful to remember that food marketing is exactly that: advertising designed to get you to eat more, all the time. And as you lose weight, it seems to lose its power.

For more, be sure to check out 10 Worst Snacks That Should Never Be In Your Pantry.