The growing popularity of fried chicken and pizza in parts of Africa underscores how fast food is changing habits and expanding waistlines.

After finishing high school a decade ago, Daniel Awaitey enrolled in computer courses, dropped out to work in a hotel, then settled into a well-paying job in the booming oil sector here.

He has an apartment, a car, a smartphone and a long-distance girlfriend he met on a dating website. So he had reasons and the means to celebrate his 27th birthday in late July. His boss and co-workers joined him for an evening of laughter and selfies, lingering over dinner at his favorite restaurant: KFC.

Mr. Awaitey first learned about the fried chicken chain on Facebook. The “finger lickin’ good” slogan caught his attention and it has lived up to expectations. “The food is just ——” he said, raising his fingertips to his mouth and smacking his lips. “When you taste it you feel good.”

Ghana, a coastal African country of more than 28 million still etched with pockets of extreme poverty, has enjoyed unprecedented national prosperity in the last decade, buoyed by offshore oil. Though the economy slowed abruptly not long ago, it is rebounding and the signs of new fortune are evident: millions moving to cities for jobs, shopping malls popping up and fast food roaring in to greet people hungry for a contemporary lifestyle.

Chief among the corporate players is KFC, and its parent company, YUM!, which have muscled northward from South Africa — where KFC has about 850 outlets and a powerful brand name — throughout sub-Saharan Africa: to Angola, Tanzania, Nigeria, Uganda, Kenya, Ghana and beyond. The company brings the flavors that have made it popular in the West, seasoned with an intangible: the symbolic association of fast food with rich nations.