This project aims to investigate the potential mediating role of circadian rhythms in the association between Body Mass Index (BMI) and cognitive functions. The objectives are to (1) collect high-quality data to better understand the relationships among BMI, circadian rhythms, and cognition, and (2) evaluate whether a nutritional intervention designed to strengthen circadian rhythms can improve cognitive functions.
In 2022, 2.5 billion adults were overweight, of whom 890 million were living with obesity (World Health Organization, 2025). Beyond the economic consequences of this epidemic, the health risks are numerous: obesity is associated with metabolic disturbances, cardiovascular and respiratory diseases, cognitive alterations, and disruptions in circadian rhythms, including disturbances of the sleep–wake cycle and altered eating patterns.
A growing body of evidence suggests that circadian rhythm disruptions may mediate the cognitive impairments associated with obesity. In children, a partial mediating role of sleep disturbances has been identified in the relationship between elevated BMI and reduced cognitive performance across multiple domains, including episodic memory and executive functions. Moreover, a nutritional intervention called time-restricted eating, known to strengthen circadian rhythms, has shown promising effects on cognition in animal models of obesity. These observations raise two questions: whether circadian rhythms could mediate the impact of obesity on cognition in adults, and whether practicing time-restricted eating could also have positive effects on cognition in humans.
To answer these questions, this project will be divided into two phases:
- Phase 1: an observational study aimed at characterizing the relationship between BMI, food intake timing, circadian rhythms, and cognition.
- Phase 2: an interventional study (time-restricted eating for 9 hours during the day and fasting for the remaining 15 hours, over 12 weeks) to evaluate the feasibility and potential effects of time-restricted eating on cognitive performance.
