Impact of dietary fiber and fat on gut microbiota re-modeling and metabolic health

•Fiber is the main dietary component used to remodel gut microbiota composition.•Fiber amplify beneficial effects of healthy diets on body weight and metabolism.•Efforts are needed to identify functional synergy among certain bacterial species and fibers.•Adverse consequences of high-fat diets are aggravated by gut microbiota.•Effects of dietary fat on gut microbiota and metabolism are not fully understood.