The liberating effect of weight loss supplements on dietary control: a field experiment

Taking weight-loss supplements may create illusion of protection against weight gain and thereby loosen subsequent dietary self-control. The current study examined whether taking weight-loss supplement would increase food intake and further tested whether positive attitudes toward supplements would increase susceptibility to overeating.

Participants were randomly assigned to take either a known placebo or a purported weight loss supplement (actually, the same placebo). After supplement provision, participants' actual food consumption at a reward buffet lunch was recorded.

Compared with controls, participants receiving a purported weight loss supplement ate more food at the reward buffet. Perceived progress toward the goal of weight reduction mediated the connection between use of weight loss supplements and subsequent food consumption. Participants with more positive attitudes toward weight loss supplements were more susceptible to the liberating effect of taking weight loss supplements on food intake.

Using weight loss supplements may produce unintended consequences on dietary self-regulation. The public should pay more attention to the notion of psychological liberation when using weight loss supplements.