Was he eating Beneful before? He probably was feeling gross, lol. Every dog I've seen on Beneful either gets bloated, or not very active, it's kind of just a not so good food. Even though Purina isn't what most would consider the greatest, I think it's better than Beneful (well, Beneful is made by Purina, but they have a few other lines that are MUCH better - such as Beyond, ONE, etc).
I personally would stay away from Beneful, but I wouldn't recommend most Purina, either, in my non professional opinion. If I had to pick a Purina to feed, it'd be "Beyond" but it still contains menadione and possibly ethoxyquin (?? not sure on this one). This dog food also contains the ingredient 'animal fat'. The pet food ingredient animal fat was determined by FDA testing to be the most likely pet food ingredient to contain pentobarbital, thus it is the most likely pet food ingredient to contain a euthanized animal.
But I'd say him being more playful means he probably has more energy and is feeling good! That's a good thing. Just occupy his mind with training, dog food puzzles, toys, chews, and things of the like. Of course exercise being the #1 -- which he probably needs more of!
