The last time the feds tried to influence the nations diet, it was a disaster. That disaster involved pushing macro-nutrient consumption away from meat/dairy (fat, protein) and into vegan/vegetarian (carbohydrate) sources. That should be abundantly clear, but you can google it as it is very well known in the usa, see for example this article front page WaPo this morning:
https://www.washingtonpost.com/news/wonkblog/wp/2015/10/06/f...
and for background, an left-wing politics view on usda the old food pyramid that has been discredited