With proper exercise fat can be converted to muscle. This isn't a question but I've been seeing mixed answers. Muscle building d
oes not convert fat into muscles. Sit-ups will build the abdominal muscles for sure. And sit-ups combined with a good diet will allow you to burn fat, making the abdominal fat eventually go away. But the fat did not become muscle.
If they want to gain loose weight then they would need to eat well, so taking in a normal amount of calories but exercising more. To gain wait, take in more healthy calories but not that much of an extreme work out.. Hope this helps.
