A formulation to increase the ratio of gastrointestinal microbiota in phylum Bacteroidetes to microbiota of Firmicutes phylum preferably includes about 20-60 mg/kg of body weight of fermentable fiber, about 10-30 mg/kg of body weight of beta glucan and about 20-60 mg/kg of body weight of blueberry extracts or any fruit or berry ingredient preparation containing similar phenolics. This formulation is preferably used to control body weight, body composition, and blood glucose regulation, preferably in humans, and is preferably administered orally, preferably twice per day.