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Cognitive effects of a long-term weight reducing diet
M J Kretsch1, M W Green, A K Fong
1U.S. Department of Agricultural, Agriculture Research Service, Western Human Nutrition Research Center, Presidio of San Francisco, California 94129, USA.
Summary
Long-term caloric restriction in obese women slowed simple reaction time but did not impair sustained attention or immediate memory. Word recall improved, suggesting cognitive benefits alongside weight loss.
Area of Science:
- Nutrition Science
- Cognitive Neuroscience
- Obesity Research
Background:
- Caloric restriction (CR) is studied for health benefits, but its long-term effects on cognition in obese individuals are not fully understood.
- Previous short-term studies have yielded mixed results regarding cognitive function during dieting.
Purpose of the Study:
- To investigate the long-term impact of controlled caloric restriction on cognitive function in obese women.
- To determine if sustained weight loss through CR affects specific cognitive domains.
Main Methods:
- A longitudinal study involving healthy, premenopausal obese women (n=14 dieting, n=11 control).
- A 15-week period of 50% caloric restriction followed by weight stabilization.
- Cognitive tests assessed sustained attention, memory, reaction time, and motor performance; body composition and behavioral questionnaires were also used.
Main Results:
- Dieting participants lost an average of 12.3 kg.
- Simple reaction time significantly slowed, but sustained attention, motor performance, and immediate memory remained unaffected.
- Word recall performance showed a significant 24% improvement at the study's end.
Conclusions:
- Long-term, controlled caloric restriction can lead to a slowing of simple reaction time.
- Unlike short-term dieting, sustained attention and immediate memory were not impaired by long-term CR.
- Caloric restriction may offer cognitive benefits, such as improved word recall, in addition to weight loss.