My Golden Retrievers have tried several other brands (one from a big pet retailer, others from a small pet supply boutique). This is the only line that they universally love. All I have to do is ask if they're ready for dinner, and they literally dance excitedly all the way to the food container and back to the dinner bowl. We have tried all five protein varieties in the Nature's Logic lineup. All of them are made with natural ingredients and no by-products. The Beef is gluten free, contains probiotics and enzymes to help with digestion, and most importantly, this is one of (if not the only) premium dog food that does not have chemically synthesized vitamins and minerals. When they say all natural, they can actually back it up! Oh, and about that interesting side effect? For some reason, the Beef variety helps firm up stools. I've spoken with several other dog owners and they have had the same reaction. If your dog is just fine and doesn't need more "firmness" just add a little water to the kibble before feeding.