I've always feed the dog left overs anything apart from chicken bones and chocolate (as there both bad for dogs) and she has never been overweight. Maybe going for 5mile+ walk and runs every day as helped that. She mainly eats complete dog food biscuits as there good for her teeth. Just supplementing her diet with two 120g tins of sardines a week until I see a veterinary surgeon on Wednesday.
They are called dogs for a reason and not humans or trashcans
The natural diet of dogs is completely different from humans, most of the table food that humans eat is actually quite bad for dogs and will lead to premature diseases in alot of cases specially when the said dog is prone to the disease ie. arthritis/diabetes etc.
A dogs really needs to stay at a strict diet throughout its life and just because your dog didnt get overweight doesnt ensure its been eating healthy. I definitely dont imply you mistreated your dog, just stating that even with good intentions the outcome can be extremely bad longterm.
I know of working dogs in Ireland that have never seen "proper" dog food in there whole lives. Dog's are naturally scavengers not just hunters and in their natural environment we eat anything edible. Giving them a lot fat diet is important tho.
Edit: Plus low salt diet
I think you misunderstood me, a domestic dog needs a healthy diet and a strict one since they dont have to fight day in/day out for "scavenged" food which a street dog might actually be "healthy" with. With proper dogfood I didnt refer to canned/bagged pellet as foodsource only.
A domestic dog is much more prone to diseases when eating whatever-they-can-get than 24/7 active wild dogs(if that is the point you tried to make), not to mention dogs are carnivores not omnivores, so they are not actually meant to eat whatever they can scavenged, its bad for them longterm. Dogs in their "natural" environment, what exactly is that? You do know that the house of an owner is the first "natural" environment of a everyday dog, so no they dont actually have a "natural" environment.
Anyhow just my 2cents, I can assure you that your dog will have a great chance of recovering if you follow my advice of sticking to a balanced diet which tries to stick to only a few regular types of food sources and not whatever-is-available to feed them.