Besides the street food available fried ignames, fried bean cakes, fried millet cakes, liver, etc.
For the AM hours, try Chez Francois' omelette sandwiches and yogurt. Around 10-11:30 you can get phenomenal porc au four at Souvenir before the hospital on the paved road and at the campement militaire they have mustard there!
Lunch options can include PP and Flamboyant. Both are in the center of town and include the basic options of To, rice and sauce, riz gras, spaghetti, and depending on the season, salad, ragout, and futu. Additionally there are some great restaurants at the main gare.
For dinner, Gaoua has a GREAT chicken place caution, only serves chicken called Le Piedmont. It is sauteed or grilled. There are also PP and Flamboyant. PP also serves chicken at night.
