This quart of milk per day was a big diry campaign that I first remember being big in the 1950's. All my older cousins downed it like it was water...I never cared for it unless it was chocolate!
And back then it was amost ALL whole milk (3.5- 4% butterfat.)
My gut feeling is that all that butterfat consumption is behind a lot of the atherosclerosis and heart disease we of a tender age are experienceing now.
I think 5-6 glasses of whole milk per day is EXTREMELY unwise...less so if you can stand the taste of that much non-fat milk. For one thing 6 small glasses (8 ounce cupfuls) of whole milk is a whopping extra 1000 calories. That might make obesity hard to avoid after a long enough period.
But even with skim milk, the consequences of all that excess calcium might prove to be a problem.
Remember, nature devised milk as the perfect food for CATTLE and even after they are weaned, they switch to grass.
And then there is the mystery: what about all the antibiotics fed to milk producing cows?