Big Boyfriend 😕

My boyfriend is quite large he keeps telling me he's got to lose weight but as soon as he says that he eats like a pig. I'm not thin myself but I've been trying but my weakness is that I struggle as I have a slipped disk in my back. He said that he was going to be a clothes size down for him going on holiday but he's still the exact same size or maybe bigger and he's going away in 3 days. It's really starting to get on my nerves as I try to lose weight but he just expects to wake up with a six pack 😒 what should I do or say to him?