About 6-8 cups a day (for a 150-200 lbs Mastiff) of quality dog food, preferably a grain free brand. But don’t feed all that at once, spread the total over about two to three feedings per day to avoid them bloating. Limit their playing and running an hour before and after feeding for the same reason. Just use a measuring cup as the dog food scoop to observe and adjust the amount of food you’re feeding them as they grow up.

If you can see their ribs clearly then they are not getting enough food. Ideally you should only be able to see the shape of the very last rib and that’s a healthy weight. From above you should be able to see a gentleman curve of their waist. A sign of being overweight during development is if their front paws pointing outwards/apart instead of straight ahead, as extra weight shows up in the pose of the front feet.

When they are young and growing, it helps to put a cup of water in the food to help their stomach handle the load of all that dry food. There are also special dog food bowls that look like a maze pattern that is designed to make them eat slower and not get sick from eating too fast, especially when they are puppies and eat crazy fast.

If all that seems obsessive or too strict, remember these dogs are man made and typically don’t even survive birth without human intervention. So strict human management is required to keep them healthy and happy.

Good luck, they are a lot of work but so worth it!