specific:

1. fruits & veggies (list at 1st page)
2. slurp (PM crazymouse or get it from Pet Shack)
3. mealworms

pre-canned or pre-packed foods aren't available at shopping malls/supermarkets.. Staple food available at some pet shops are also suspicious.. i mean in term of ingredients..

so it's just best to stick on fresh fruits & veggies, slurp and mealworms/crickets as basic diet for gliders..
p/s- it's great if you could solve the best diet for the gliders.. proper diets are important for glider and any other pet..