Gabonese cuisine is hearty, heavily spiced, and built around starchy staples, fresh fish, and whatever the forest provides. French colonial influence means you will also find baguettes, croissants, and decent wine in Libreville, but the local food is far more interesting.
Poulet nyembwe is the national dish and you should try it early in your visit. It is chicken simmered in nyembwe, a rich sauce made from palm fruit pulp that gives the dish a deep, oily, earthy flavor. It is served everywhere from roadside stalls to upscale restaurants. When it is good, it is very good.
Fufu -- a dense, stretchy ball made from pounded cassava or plantain -- is the staple carbohydrate and accompanies most meals. You tear off pieces and use them to scoop up stews and sauces. It takes some getting used to in texture, but it grows on you.
Dongo-dongo is a popular okra-based stew, usually made with smoked fish and served over rice or fufu. The okra gives it a thick, slightly slimy consistency that is more appealing than it sounds.
Brochettes are the universal street food: skewers of marinated chicken, goat, or fish grilled over charcoal, often served with a spicy pepper sauce and fried plantains. You will find them at roadside grills across the country, and they are reliably good and cheap.
Atanga (bush butter) is a seasonal fruit with a rich, creamy flesh that Gabonese people spread on baguettes or eat alongside savory dishes. If you visit between June and September, try it.
Bush meat, including antelope, porcupine, and monkey, features on menus outside Libreville. It is a traditional part of the diet, though conservation concerns make it a fraught topic.
In Libreville, you will find French restaurants, Lebanese food, and a handful of Asian places alongside local spots. Outside the capital, your options narrow sharply. In smaller towns, expect rice, fish, and whatever is locally available.