My Niece's Weight Problems

Worried about her daughter being so skinny, my SIL did everything she can to help her gain more weight. She gave her vitamins and fed her nutritious food (that she rarely finish) but her weight remains the same. We didn't realize that gaining weight could be a problem too. If only I could exchange places with her (hahaha). We did some research on how to increase muscle mass and learned a lot of things. I hope the articles we found can help her start gaining weight.