4. Discussion
Our study demonstrates that dietary advice aimed at increasing protein intake from an average of 0.8 g/kg aBW/day to 1.2 g/kg aBW/day in community-dwelling older adults did lead to an increase in protein intake, but does not affect gut microbiota composition, appetite, or brain activity in response to food-related stimuli. As the PROMISS study has shown that the intervention does improve 400 m walk time or leg strength [In our study we measured the effect of a dietary intervention on appetite using an adapted version of the SNAQ appetite questionnaire [We hypothesized that protein-induced changes in self-rated appetite or brain activity patterns would be partially mediated by the gut microbiota through the gut–brain axis. However, in addition to not affecting appetite or CNS responses to food cues, our intervention did not affect the composition of the gut microbiota. Neither the alpha diversity (within-sample diversity), nor the beta diversity (between-samples dissimilarity), nor the bacterial abundance of individual taxa were affected. This finding contradicts the study by David et al. [