I'm open to any ideas that you've experienced to motivate people to eat less and work harder.
Why do people like junk food? It's good. Why do we not like veggies and such? They don't taste as good. Children may be turned off to certain vegetables because of plant toxins.
Take the new school members out to an oriental restaurant. Let them sample the healthy stuff and find out that it can
be good. I love seafood and freshwater fish, rice, etc. I would live on a local restaurant's hot'n'spicy shrimp if I could afford it. If you're not familiar with this dish (I don't know the Chinese name) it's shrimp in an eye watering sauce mixed mixed with onion and broccoli. It comes with a side of sticky rice.
Keep up the tradition for special events- if a student should make a promotion, etc. Or just for the heck of it. Maybe even serve snacks afterward.
Look at the bright side though: At least these guys are getting up from the television, Nintendo, whatever, and are coming to a class where they can be active.