IMPAIRMENT OF COGNITIVE PERFORMANCE ASSOCIATED WITH DIETING AND HIGH-LEVELS OF DIETARY RESTRAINT

Seventy women students were tested on a short battery of tasks assessi ng cognitive performance. They also completed self-report ratings of m ood, the Dutch Eating Behaviour Questionnaire (DEBQ) to which was appe nded several additional items concerning their recent dieting behaviou r, and a 24-h dietary recall. Heart rate was measured before and after testing. Compared with nondieting subjects with low to moderate score s on the restraint factor of the DEBQ, subjects (n = 15) who reported that they were currently dieting to lose weight displayed impaired per formance on a vigilance task and also tended to show poorer immediate memory and longer reaction times. Highly restrained eaters who were no t dieting at the time of testing, on the whale, performed at an interm ediate level on these tests. In contrast, the dieters tended to show t he best performance on an undemanding finger tapping task, indicating that they were not slowed in their fine motor responses dr lacking in motivation to carry out the tasks. Poorer cognitive functioning during dieting could arise as a direct consequence of the effects of food re striction on energy metabolism or other physiological mechanisms-the d ietary records indicated that the current dieters were eating at about 70% of maintenance energy requirement. However, it is also possible t hat cognitive performance is impaired during dieting due to anxiety re sulting from stressful effects of imposing and maintaining dietary res traint.