Now you don't need to eat protein powder, the most important thing is carbohydrate intake. If you really want any tonic, you should add muscle powder. Eat three meals normally, you can eat every meal when you are full, and then add one or two extra meals. Details are available online, but don't learn that kind of cooking. Now you need to gain weight and ensure that you have excess calories every day. Boiled meals are low-fat foods that are not suitable for thin people to gain muscle. Just eat as usual, just eat one or two more meals. Of course, this should be added slowly, almost once every two or three months, and six meals a day if conditions permit.