If you don't train, just eat muscle-building powder, and your gastrointestinal absorption is ok, then muscle-building powder will make you gain a certain weight. If your absorption is not good, then muscle-building powder has little effect on you.

The main purpose of muscle training is to make your muscles hyperemia, let your muscles get nutrients in the blood, and let your stomach absorb nutrients better. Eating muscle-building powder in this way can be effectively absorbed, and it can also turn your body fat into muscle and make your muscles compact and expand.

The nutritional components of muscle-building powder are carbohydrate 80% and protein 20%.

Carbohydrate is equivalent to rice, and protein is like an egg. Without training, muscles can't effectively absorb the nutrients in the muscle-building powder.

So eating muscle-building powder is equivalent to eating rice, just turning rice into powder to make you absorb it better. If you eat two bowls of rice, it is equivalent to eating a spoonful of muscle-building powder, so you have no training and only eat muscle-building powder, which is equivalent to eating several bowls of rice more than usual.