I could be making huge assumptions here. But I imagine the GP's experiment was as simple as focusing on "recommended calories" (which is 2000 per day) and secondarily, keeping under/over certain nutrients (low sugar/cholesterol/fat, high vitamins).
Food pyramid was much less scientific and more of a basic guideline for school children (and yes, the dairy campaigns were very successful, though dairy at least has nutritional value and usually a good "fill" factor). But I don't think any of those hard nutrient recommendations were every challenged.
Food pyramid was much less scientific and more of a basic guideline for school children (and yes, the dairy campaigns were very successful, though dairy at least has nutritional value and usually a good "fill" factor). But I don't think any of those hard nutrient recommendations were every challenged.
Were they? I honestly haven't looked into it.