Individuals with obesity tend to be more swayed by food marketing—but when their weight drops, so does their responsiveness to marketing claims. This is according to a study in the Journal of Consumer Psychology. The research showed that both obese and normal-weight participants underestimated the calorie content of not-so-healthy snacks that were branded as healthy, but the effect was more pronounced in people with obesity than in those who had lost a significant amount of weight.

In theory, this difference in how food advertising is perceived could make it more challenging for overweight individuals to drop pounds. It’s not clear whether people become less susceptible to marketing because of physiological changes following weight loss—including hormonal changes, neurological shifts, or alterations to gut microbiota—or because of psychological changes, including an increased desire to alter lifestyles and habits.

See also: Modern Food Marketing Needs Old-Fashioned Nutrition Help