Before she was just a dietitian at a hospital. Working for the AIS, I assume she specializes in sports performance, which would not make her regular.
You said you have to watch your Cals in because you can't do as much cardio due to injuries, In the context you'll get fat if you don't. It's not the lack of cardio, its too many calories in for the output.
Exercise is merely a way that allows/requires you to eat more calories, depending on goals, not the other way around.
edit: lifting heavy weights works you out enough for general fitness. It's not going to help with sport specifics. Again, weights won't make you look fit, a good diet does that.