@indermitter It can take three months to gain 5 pounds of muscle. Eating 1,500 calories a day should cause her to stay the same weight. OP says they're gaining more and more weight. Something's not right.
@indermitter While that is true, it takes a lot of work to actually gain muscle. It doesn't happen as quickly as people think, and OP should seek medical advise if they are only taking in 1,500 calories are are still "gaining more and more weight."
@andrewmicheals DONT BE DISCOURAGED!
5 minutes today, 6 tomorrow, 7 the next, 7 the next, 8 the next, 8 the next, 9 the next, 10 the next, etc.
Just keep increasing and you'll be back to 45 in no time.