Not white or black but I live in Canada and most of my friends, coworkers and extended family are "oyinbo". The carb of choice for whites in the US and Canada is potatoes, pasta and bread. Yams are eaten but its not very common (usually eaten as yam fries though). Beans are a food that is common in Latin American cuisine so many Americans who live near the Mexican border will eat it but elsewhere not so much. I have never heard of garri (cassava flour) so no, its not something people drink here.

Despite yam and beans not being the staple of choice here they are still easy to find in a Canadian supermarket.