I'd agree, I tend to not give them anything with protein as too much will cause an issue with how their body stores it, which can then cause issues when fed to your dragon.
I give mine the veggies that start to get a little iffy or the stuff I bought for my dragon that they no longer like. I buy fresh greens weekly for the dragons, about 99c for a bundle of 1 fresh kind of green, and whatever's left over goes to the roaches when the new fresh greens are in. I try to only give the roaches enough to eat in a small time to not have molding food or increase the humidity too much.
I also feed them apples. I'll buy a bag of apples on sale and they keep in the fridge very well, so I'll cut them into slices and plop them in. Usually 1 apple at a time until it's all gone, for the above reasons