Users report better digestion and even better breath when switching over from other brands. (mysweetpuppy.net)
In other words, you should eat huge amounts of food for several months while training hard and then switch over into «cutting» mode to shed fat. (fitnessandpower.com)
The same goes for cat food: Start with whatever your newly adopted cat is used to from the shelter, then gradually mix in your preferred brand before switching over completely. (hartz.com)