Effects of Intentional Weight Loss on Physical and Cognitive Function in Middle-Aged and Older Obese Participants: A Pilot Study

Objectives: Obesity is a risk factor for cognitive decline and dementia. Whether weight loss improves cognition in older obese adults is not known. The objective was to investigate the effects of intentional weight loss on physical and cognitive function in middle-aged and older obese adults attending a weight loss clinic. Method: Eleven male and 39 female nonsmoking, adult obese (body mass index 30-50 kg/m(2)) participants were recruited. Participants were stratified by age: middle aged (30-59 years) and older aged (>= 60 years). The weight loss target for each subject was 8% to 12% of initial body weight. Information on anthropometry, bioelectrical impedance, hand-grip strength, Mini-Mental State Examination (MMSE), Short Portable Mental Status Questionnaire (SPMSQ), and Trail-Making Test (TMT) A and B were collected at baseline and after weight loss. Results: At baseline, older participants showed a nonsignificant trend for lower global cognitive function (MMSE, SPMSQ) and significantly slower processing speed (TMT-A). Twenty-one participants completed the weight loss study. The average weight loss relative to baseline was 9.7% +/- 2.1%. Weight loss was associated with significant improvements in hand-grip strength and cognitive function (MMSE, TMT-A, and TMT-B). MMSE scores improved significantly only in older obese participants (p < 0.05). Conclusions: Weight loss in middle-aged and in older obese participants has a beneficial effect on cognitive and physical function. If confirmed in future trials, weight loss can significantly affect public health strategies for the prevention of dementia as well as on the clinical management of obesity.