I use Victor "All Stages", beef formula and my dog looks great, has a lot of energy, and has a very shiny coat. His poop is very solid and he doesn't have much of it, so I know he's digesting well. I started out on the puppy formula. The only problem is that he doesn't seem to like it(current formula or the puppy formula). I say that because when I feed him, he rarely eats it right away. He sniffs it and walks away and will sometimes go all day without eating until he finally gets so hungry that he can't wait any more. When I feed my Dachshund(who eats basic Walmart food), Mojo would inhale every bit of it if I let him. He loves it! I switched to the Victor Chicken & Brown rice w/ Lamb meal formula with the bag I have now and he seems to like it better, but still doesn't want it as much as the cheap Walmart food. I'm torn because he looks great and the food seems to be quality food, but he just doesn't seem to like it. I often times pour some chicken broth on the food and then he'll eat every bite.
Might be a good idea to have him checked out and a cbc run at your vets.
Of course you know just because the Walmart food is tasty doesn't mean it's a quality food. Probably just has a goodly amount of dog delicious grease poured on it.
I'm sorry your boy doesn't care for his food. There are many reasons a young male dog goes off his food. Be careful about adding toppers to get him to eat or changing foods a lot to encourage him to eat. You could make a picky eater out of him. A proven method that might help is to gibe him 10-15 minutes to clean his food up and then pick up any leftover. No treats or anything till next regular feeding. Put food down for 10-15 minutes and pick up left overs and nothing till next regular meal. They usually learn pretty quickly to eat while they have the chance. You could also do this in his crate so he doesn't get distracted.
If limiting meal times doesn't work you might consider changing foods. Next step would be considering neutering as that can make a difference.