Signature Doggies

I just ask a question on what food dogs can’t eat and there was a long list, practically almost everything.
I am planning to get a dog and want to know everything I can.

I have 2 dogs, a jack russell and a rat terrier. We used to always make sure there was food in there bowels at all times. But then the jack russell started to gain a ton of weight. Now we follow the back of the dog food bag guideline. It is premium dog food. My dogs get normal activity, but now they act like they’re starving, is this normal? My dogs are healthy otherwise.