A very long time ago, 1981 to be precise, I intended to pursue a masters degree in agronomy, with a focus on how well various agricultural systems supported balanced nutrition for those dependent upon them. I didn't even last through the first semester, assembling the prerequisites, but that was the goal I was aiming at.
Fast forward to 2008.
Take your standard recommendations as to what constitutes a balanced diet; work up a meal plan for a week, and from that a shopping list; go to any supermarket and price out your shopping list. You'll find that some items, basically those that can be grown and harvested without the use of hand cultivation, are relatively inexpensive, and others, those requiring manual labor for at least one step in the process of getting the crop to market, are relatively more expensive. It's all too tempting to just go for the less expensive items and leave out the more expensive items, maybe using vitamin supplements to make up for what's missing, maybe not.
This is a hidden cost of current agricultural practice, that it makes a nutrition-poor survival diet relatively inexpensive, while a really balanced diet is unaffordable to many.
Intensive cultivation using robotic land management could do a lot to make currently expensive produce, and therefore a balanced diet, more affordable.