Fattening others

I want to fatten this girl up. The problem is, she already eats fast food pretty much every meal. She’s got a little heavier through out the years, maybe 15 pounds. What should I feed her that’s good for packing on pounds? Fast food?

ice cream, ultra processed foods, sweets.

Pizzas were my saviour. Heat 2 but always serve sliced and eat a few pieces yourself.
It's about denial on their part, they will want to believe it was just one pizza and you ate half haha.
It's works, xx

Variety variety variety. And always have more food available than she can finish. Even if she eats a lot, it doesn't even make much of a dent.