A product for use in the treatment of obesity, the metabolic syndrome, type 2 diabetes, cardiovascular diseases, dementia, alzheimers disease and inflammatory bowel disease comprising at least one isolated bacterial strain from the species Prevotellaceae, wherein the strain is selected from the group consisting of Prevotella copri, Prevotella stercorea, Prevotella histicola, Prevotella ruminicola, Prevotella Bryantii 25A and Prevotella distasonis. The product may be a food product.
