They try to remove lead from soil by growing certain plants that collect it.

VOA: special.2009.06.09

The plants can be deficient in certain things, especially fat soluble vitamins that come from meat and from essential amino acids.

植物中缺乏某些物质,特别是脂溶性维生素,那些只能从肉类和必需氨基酸中获得

耶鲁公开课 - 关于食物的心理学、生物学和政治学课程节选

There are other things that would qualify as food, but the not too much of course has to do with over-- intake of certain nutrients, the calories; and then eating mostly plants tends to be a pretty good idea.

辣奇多绝对不能算作食物,至于"适量饮食"则应参考,某些营养素及热量的摄入量,而"植物为主"是一条非常好的建议

耶鲁公开课 - 关于食物的心理学、生物学和政治学课程节选