In 2050, older adults (65+) will reach 20% of world population with sarcopenic individuals representing a third of them. Specific nutritional strategies based on proteins coupled or not with exercise have shown some beneficial effects to limit sarcopenia but depending of the physio-pathological state, they may not be optimal or not applicable in case of poor appetite or disabilities to perform exercise.Hence, complementary strategies independent of food intake need to be developed to limit sarcopenia. We recently observed on small intestine-resected patients a specific microbiota with a tremendous increased in Lactobacilli. Following the transfer of this specific microbiota in axenic rats, we showed an improved energy metabolism regulation which could be an adaptation of the gut physiology and metabolism to optimize the challenged utilization of nutrients in those patients. We hypothesized that this microbiota could be of interest to optimize energy utilization in malnourished frail elderly and then to limit sarcopenia.