My last dog had constant food and regulated himself. Never got fat.
My current dog would eat till she burst under the same regimen.
Ultimately a fat dog is the owner's fault with rare exceptions.
My recent adoptee was malnourished and picky, so for the first month or two I'd fix him a special bowl with a little cheese and beef broth which he couldn't resist, but nowadays, I'll fill their bowl in the a.m. before I leave, but it seems like they usually wait until I come homr for lunch or in the evening before they start to really dig in. Fortunately, the three of us are blessed with fairly high metabolisms which (knock on wood) seems to have kept all of our weight down.