honestly agro forestry and food forests are an amazing potential for local food production with a permaculture and sustainability in both environmental and infrastructure impact.
Growing nut trees with smaller fruit trees around them, and then shrubs, vines and ground cover crops in clusters where the deep roots of the nut trees grab deep mineral nutrients, the wider fruit tree roots spread and distribute (with a fungal network) nurtients and provide habitat for bugs and worms that compost the leaf litter of the trees into rich compost for the plants under them and provide protection from direct sunlight, wines can climbtrees, beans pull nitrogen from the air and add it to soil and the birds that live in the trees and shrubs eat insect pests and excrete fertaliser.
Favoring Perennial crops means pretty much free food after the planting ever after. And moving away from grains and replacing them with nutmeal and bean flours would go a very long way to being able to grow more on the tiered levels of a food forest, while nutritionally being a better option and evironmentally too.
more to the point of diet, we need to move more in the direction of using vegetables and leafy greens as the majority of our dietary foods. Nutritionally they are superior. And I can say from experience that eating 3 cups of mixed green salad makes me fill up faster and full longer than eating two dinner rolls; meanwhile my nutrition needs are better met and it's effects on blood pressure and cholesterol (not to mention body fat and fitness) are much better for vegetables and leafy greens.
Throw in insect flour, eggs, mushrooms, poultry and fish; and you have a healthy food supply that can support all the nutritional needs of a family on less than an acre of land if done through food forests. If you do some of it in home aeroponic and hydroponic setups and some of it in virtical urban farming buildings you can easily supply food needs for a small city.