Carbohydrate supplements are a type of weight gain supplement that mainly consists of carbohydrates. Carbohydrates are an important source of energy in the body. These carbohydrate supplements can contain simple or complex carbohydrates, but are generally very low in fat. Taking carbohydrate supplements after exercise can create better recovery, and it is used by bodybuilders and serious athletes to gain weight. These supplements are especially interesting for so-called hard gainers who need a boost to their weight gain.