Hungry cat or just trying it on?

[craftysewer]

I have a young female cat 18 months old who has been given dried food ever since we got her. She very very rarely is given treats. Dish is always full of food and if we accidentally don't keep it filled she certainly lets us know . We went away for a week leaving her in the car of my 18 and 20 year old daughters and on our return she is always begging for food. I blamed the DD's at first but am wondering if something else is going on. Her food hasn't been changed for anything different. Had her to the vets this week for a lump on her right flank and she is currently being treated with antibiotics and painkillers. She has lost 10% of her body weight in the last few months. Vet said she's not too bothered and will weigh her again next week when we go back. Do I need to be supplementing her food with anything? She pinched a bit of pizza tonight and last night both her and the dog were sat looking at me in the kitchen with that 'feed me your food now' look even though she had food in her bowl.

[PigletJohn]

somebody has trained her to beg.