Complan contains protein for the growth and maintenance of muscle, B vitamins to help release energy, calcium and vitamin D for the maintenance of bones, and vitamin C and iron to help support the immune system. Complan contains the equivalent protein, carbohydrate, vitamins, and minerals of a light meal, along with some fats and sugars. Complan can be incorporated into your diet when your appetite is reduced, though a normal healthy diet should be resumed when possible.