Well, this guy has a different opinion:
Rancid, heavily preserved fats are extremely difficult to digest and can lead to a host of other health problems in your pet. Digestive upsets, especially throwing up bile or food, diarrhea, gas, and bat breath, are all linked to this.
http://www.purelypets.com/articles/whatsinfood.htm
If you have the time, you can google "dog food ingredients that cause gas" and see the opinions of others and choose a dog food that way.
I feed Natural Balance Ultra Premium with baked chicken on the side.
