The amount a dog needs to eat doesn't really scale linearly with their size. Giant breed dogs eat a lot, of course, but not really as much as you might imagine.
Besides, letting a giant breed dog get fat would be seriously bad news since their joints are under a lot of stress as it is. Got to watch their diet like a hawk.
That looks like an irish wolfhound to me, is that right?
Yes, that's Marley, and he is an Irish Wolfhound.
Early on (first couple of years, while he was growing) we fed him "large breed" dog food. But for the last year he's eaten normal dog food.
He eats his food... then he eats the two huskies food... then the cats food... and if you don't watch him around supper time he'll walk over to the counters and/or table and eat any food on those, too.
Sometimes he even eats couches.
He can nose-bump an 8' ceiling playing catch indoors, with his hind legs still on the ground.
He's good around kids, although you have to protect little ones from his gigantic tail.
At 3 months old he was a lap dog.
At 3 years old he is a 'fill the entire bed dog' (That's a queen size)
(I once woke up and was paralyzed, couldn't breathe. A thunderstorm had rolled through, and for a brief moment while I was in the half-sleep fog I thought I was dying. Then I realized I had a 180 pound dog laying over my chest. My arms down at my sides, pinned under the blankets, I couldn't move. Barely got enough of a breath to yell for my wife "GET THIS DOG OFF ME". To which she replied, after a moment, "I CAN'T MOVE EITHER!". He had pinned us BOTH under the blankets, afraid of that thunderstorm...)
This is my 5th grader.
They both help out in the garden.
And that's my wife, with polite doggies begging for treats. She's 5'9".
Of course he can get drinks standing next to the kitchen sink.
He's the most loving, loyal companion I've had in life.
As far as loyal - do not approach the house when I'm not around. He will stand his ground and keep you from getting close. If you enter the house unannounced, it is bad news.
When I'm gardening, he stands 'point' and watches. Anyone that approaches gets stopped, period. He will move between me and them and growl - the sort of growl you can feel in your feet, as it travels through the ground.
At night, he's alert and will let us know when deer are in the yard; or if someone is out poking around outside.