I use fish flakes to gutload my worms and roaches. I have used them in the past for crickets also.
This is one of my back up items I always keep on hand. Not being able to drive can sometimes be an issue when buying large amounts of baby food.
I also use Science Diet dog food for my crickets. In fact I use that as a staple for them, and feed my mad scientist mix only 24 hours prior to feeding time.