text: hi i am 24, i want to gain weight and build my body , i just weigh about 45 kg.pls can anybody help me out? i feell low, would like to have tonic's name or any methods of geinning weight. sam,proteins are required for building muscles, so having high protein foods like eggs, milk,  peanut butter, protein shakes will help you. eat more of starchy foods.starchy foods contain a lot of carbohydrates. you can find more information to gain weight at  http://www.toloseweight.org/gainweight.html