Whether she sees a shrink, an orthopaedist, goes to zumba, has a personal trainer or nutritionist is irrelevant to this. She can do as she pleases outside of her duties although obviously an au pair with a PT will inevitably rub mums up the wrong way in nappy valley (how dare she)
Most young people eat a lot and given the chance will munch through anything and everything in the fridge, whether they work out or not.
Saying that, helping yourself to a pack of king prawns as a snack? Just no. Protect the prawns!
This is why is it imperative people work these details out BEFORE someone starts.
A friend gives her AP 30 per week, whether she is there or not. Even if family on holiday they will still need to eat