I’ve also heard of shopping only on the edges of the grocery store.
So – vegetables, dairy, meat, eggs, and ice cream (try Breyers – only 4 ingredients and I can pronounce all of them).
I will also add the freezer aisle as frozen vegetables are now flash frozen at the best time of harvest. So the fresh veggies going bad is a thing of the past and the canned vegetables with salt and other preservatives is no longer needed. I have bought frozen veggies on sale then dehydrated for storage, works pretty well (caveat – I have never done nutritional studies on the rehydrated veggies)