Answer:
Yes.
If a person eats enough food and doesn't exercise enough, they will become obese. Africa is no different than any other place. Also, there are plenty of obese foreigners that visit or move to Africa, in addition to all of the native obese people.
Also, a genetic or physiological condition could be the cause of obesity, despite average food intake.
Compared to Africa, America has a higher incidence of obesity. In recent years, as Africa is becoming more Westernized, so too are their diets which is causing a host of new nutritional issues, inlcuding obesity.
Oh, and especially in Mauritania.
Mauritania is a country in Africa in which girls are fattened up to huge sizes before marriage, to make them more attractive to their grooms.