The presentation by Isabel Beerman from the National Institute on Aging explores the effects of caloric restriction (CR) as a scientifically supported method to extend lifespan and delay ageing. With decades of promising research in model organisms, Beerman highlights efforts to translate these findings into human-relevant studies through experiments on non-human primates.

Key Points:

The research reinforces the potential of caloric restriction as a viable ageing intervention, offering insights into metabolic and microbiome-based mechanisms. While promising, future studies must address sex-specific responses and explore larger sample sizes to enhance translational relevance.

Caloric Restriction and Ageing: CR is established as one of the most effective interventions to extend lifespan across various species. However, translating these results to humans remains challenging due to adherence issues and physiological differences. Alternative methods, such as intermittent fasting or time-restricted diets, are being explored.

Non-Human Primate Studies: A midlife CR intervention (four days of restriction followed by ten days of normal feeding, repeated over 10 cycles) demonstrated sustained weight loss and improved metabolic and physical health in male primates. Females, however, showed weight regain, revealing significant sex-specific differences in response.

Mechanisms Underlying Effects: The intervention induced a shift in metabolism from carbohydrates to lipids during restricted periods. Males maintained lower body weight post-diet, potentially due to "metabolic resetting," while females displayed a compensatory mechanism favouring fat retention.

Microbiome and Health: CR was associated with increased diversity in gut microbiota, a marker of better health, alongside specific beneficial shifts, such as a rise in Akkermansia species. These microbiome changes were transient but built cumulatively over repeated cycles.

Potential Applications and Limitations: The study underscores the potential of short-term, cyclical CR interventions to produce long-lasting health benefits, particularly for males. However, the pronounced sex differences highlight the need for tailored approaches in human applications.