When you eat foods; you should consider a few factors. These include sugar content, mold content, glycemic index, and inflammatoriness (new one for me). Trying to find foods that fit the bill for all of these is sorta hard, but in general almost anything that is a vegetable is pretty healthy and beneficial for your recovery.
Bananas contain about 24g of sugar per banana, so avoid them at all costs despite it having FOS. Artichokes would be a good alternative.
I only eat about a half cup of buckwheat a day myself, so don’t indulge in it too much (to recap). I eat about 2 slices of coconut/buckwheat bread (double batch) per day as well. I would consider this a small amount. If you eat 1 cup or more of buckwheat a day; I would consider reducing it.