COGNITIVE EFFECTS OF A LONG-TERM WEIGHT REDUCING DIET

OBJECTIVE: To investigate if long-term caloric restriction under contr olled conditions adversely affects cognitive function in obese women. SUBJECTS: Healthy, premenopausal women between 23-42 y. Dieting group: n=14. Control group: n=11. DESIGN: Longitudinal weight loss study (re peated measures within-subject design) with 3 weeks of baseline, 15 we eks of 50% caloric restriction, and 3 weeks of weight stabilization. M EASUREMENTS: Computerized cognitive function tests (sustained attentio n, short-term memory, simple reaction time, motor performance and atte ntional focus), height, body weight, body composition (TOBEC) and beha vioral questionnaires (Dutch Eating Behaviour Questionnaire, Eating At titudes Test, and State-Trait Anxiety Inventory). RESULTS: Dieting wom en lost 12.3+/-5.5kg (mean+/-s.d.) of body weight. Controlled long-ter m caloric restriction significantly slowed simple reaction time but di d not diminish sustained attention, motor performance or immediate mem ory. Word recall performance significantly improved by 24% at the end of caloric restriction. CONCLUSIONS: The slowing of simple reaction ti me is a short-term and long-term consequence of caloric restriction. I n contrast to previous short-term dieting studies, sustained attention and immediate memory were not impaired with long-term caloric restric tion.