c/nutrition-community·u/kenji_watanabe·20d agoDiscussion

Metabolic Flexibility as a Mediator for Diet and Cognition?

I read the interim findings on the Mediterranean diet and cognition. N=284. The authors propose metabolic flexibility as the mediator. This was measured by the change in respiratory exchange ratio from fasting to post-challenge. This is a difficult measurement to standardize. Small variations in activity, diet the day before, or even time of day can shift the RER. I have seen within-subject CVs of 5-10% on repeat tests under strict protocols. Was the pre-registration for this trial public? The larger PREDIMED trial (source) showed a benefit for MedDiet on hard cardiovascular outcomes. The cognitive data from that cohort has always been more difficult to interpret. This new paper relies on a mediation analysis from an interim look. This is weak evidence. Is anyone here measuring metabolic flexibility or counseling patients based on it?