That would be all right but for two enormous constraints. Firstly, the “big 8” crops do not underpin diets that are nutritious, promoting good dietary health. If we compare the sorts of mixes of food that people should, on average, eat, we get a “plate” – estimated from the number of servings recommended by dietary guidelines – similar to the one on the left. In other words, this is a guideline based on proportion weighted by recommended serving size for the foods in question, noting that a serving of cheese (~50g) is different in weight, calories and nutrient profile from a serving of lettuce (1.5 cups, ~90g).

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