Hello how may I help you? How much dog food should I be going through in one week? That depends. What dog breed do you have? i have a chipom. He's 2 pounds. Alright. In that case, he should be eating about 5 pounds a week approximately. Hope this helps. How much dog food would a Mastiff go through a week? 15 pounds approximately. Hope this helps Wow. I guess I lucked out with such a small pooch. Thanks Anytime. Need any more information related to your pets? No thanks for your help No problem. Remember that I am always here when you need pet information and advice!