Protein and fiber are two critical ingredients in maintaining a healthy body weight. Protein is used for every process the body undertakes. It is crucial that we get enough healthy protein in our diet to maintain our lean muscle mass. The other main ingredient in the FitSmart Bar is fiber. Fiber plays several important roles in maintaining healthy body weight. It helps to slow down the rate at which the body converts carbohydrates into sugar, making it a powerful weight management tool. Fiber has no calories and fills the stomach, making you feel fuller for longer periods of time.