Kisii is a working town and its food is honest and cheap. Most travellers eat at one of the hotel restaurants — the Sahara Springs, the Zonic and the Mash Park all do reliable Kenyan and Indian dishes — or pick up something from the matatu-stand stalls.
Try kienyeji chicken, the lean free-range bird that the Gusii raise on their smallholdings, slow-stewed and served with ugali. The local greens — sukuma wiki (collards) and managu (African nightshade) — are excellent. For something sweet, look for mursik, fermented milk traditionally aged in a charred gourd; it is more usually a Kalenjin thing but turns up in Kisii markets too. Goat nyama choma is on every menu in town.