In 1942, the Canadian government published “Canada’s Official Food Rules”, which was the first nutritional guide that it had produced. (The name was later changed to “Canada’s Food Rules” and then to “Canada’s Food Guide”.) The initial Official Rules treated milk as a food category all its own, recommending half a pint of milk a day for adults and more than one pint for children. (The Canadian government page on the history of its food rules and food guides is here.)
Naturally, milk manufacturers saw this as a marketing opportunity. Silverwood’s Dairy Products included a reasonable approximation of the Food Rules, naturally listing milk at the top:
And the Milk Foundation of Toronto also included the list of foods, in a slightly different order but once again with milk at the top:
The 1944 Canada’s Food Rules actually increased the recommended quantity of milk, suggesting one-half to one pint for adults and 1 1/2 pints to one quart for children. The recommendation reverted in 1949 to its original level of a half-pint for adults and a pint or more for children.