In a volunteer sample of female undergraduates, concerns about eating, body weight and body shape were found to increase with the level of self-reported dietary restraint. These concerns were greatest, however, in a subsample of subjects who were currently dieting to lose weight, and greater than in equally restrained but non-dieting subjects. Furthermore, the dieting subjects performed less well on a demanding cognitive task than the non-dieting subjects. These results show that it is important to distinguish between dietary restraint and actual dieting behaviour. They also highlight the need for further research to examine the effects of dieting on cognitive functioning.