If she wants to get bigger, then I'd get her started with Greyskull LP. It's a fairly basic beginner weight lifting program that, when combined with a caloric surplus, will get good results for size and strength. There isn't much work involved (just three sets on 2-3 exercises; doing more is counterproductive for beginners) so it won't use as much energy as a cardio or circuit intensive routine.

A couple of protein shakes with milk/almond milk are enough to get a caloric surplus going. You only need 250-500 extra calories to make good gains, and you can easily get that with a shake or two.