Question: how much should i feed my 1 year old english mastiff?
Answer: A full grown mastiff will grow to be about 150-200 pounds1. Which means a 180 pound mastiff2 with what the site considers a "typical" activity level, and food with a kcal amount of 320 per cup3. You're looking at roughly 10-11 cups of food twice a day. Alternatively, that would be about 2 pounds of food each meal.