Supplemental enzymes assist in breaking down the food you eat thus making the nutrients in the food bioavailable to your body. In other words, it makes your digestive system more efficient. When the food you eat is not properly digested, it can stay in your digestive tract too long where many undesirable things can happen. Undigested fat will turn rancid; undigested carbohydrates will ferment; and, undigested protein will putrify. Not only does this create an environment which can lead to various diesease, it certainly prevents the nutrients you are eating from helping to build muscle and body tissue. A more detailed explanation of this can be found by taking The Digestive Enzyme Tour.
Digestive enzymes help build and maintain a healthy body. In this regard, digestive enzymes help people to gain weight and they also help others lose weight. Unless there is a disease condition that upsets the balance, a healthy body will generally find its own balance, with weight control then becoming a function of how much you eat and how much exercise you get. Digestive enzymes assist the body to get back into its natural balance.