I used to have two German Shepherd x Australian Kelpies (lived to be 19) which were fed a variety of foods, mostly stuff we prepared ourselves.
The key to any good diet is to have a variety of ingredients to maximise the number of nutrients available.
We used to cook up some veggies (peelings, leftovers, just bought), some brown rice, 1 or 2 weet bix, some meat scraps & cut offs couple times a week. They used to get our dinner left overs nearly every night - potatoes, carrots, peas, beans, spinach, etc... Along with any cheap cuts of meat left raw.
They were given whole chicken carcasses, rabbits, prawns, shellfish, crab, & various cuts & types of fish. They also used to eat bananas, apples & grapes, along with all types of bone. Never given cooked chicken bones, though.
They also got 4 cups of dry food each day. I don't remember the old stuff we fed them, but we changed to something called 'Woof-Bix', which they enjoyed a lot. Neither of these dogs had food allergies, as they were raised to eat virtually anything & everything.
They were also exercised a lot, so there was never a weight problem.