I have been revisiting Stigler's diet problem with Tesco/Sainsburys nutrition and price data: https://github.com/osmarks/misc/tree/master/stigler.

After protein quality fudge factors, the optimal (cost-optimized under macronutrient constraints, micronutrients ignored because there's not good enough data) diet is apparently a combination of wholemeal pasta, bacon, dog treats, dog nontreat food and "mornflake groats".