Early one Friday evening at a McDonald’s restaurant in Johannesburg, a large group of young executives enjoyed their post-work, pre-night-out dinner.

Wearing glamorous designer suits in the shadow of the city’s stock exchange, some diners delicately dunked their chicken nuggets while discussing local politics and the previous week’s stock market fluctuations.

“We’d rather come here than a fancy steak house,” one diner said. “We like the vibe and the food.”

Some fast-food chains in parts of Africa enjoy a more aspirational image than they do in the West. A fuller frame and fatty foods are, in some cultures, firmly associated with wealth.

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In Kenya's capital, “The Colonel” is king. When a branch of KFC opened in Nairobi last year, customers had to queue for up to 90 minutes to get their hands on a sought-after bucket of fried chicken.

That might help -- in a very small part -- to explain why Africa’s waistline is growing so rapidly. Obesity, a problem more associated with the developed world, is a growing issue on this continent. The trend is threatening the lives of the very young.

New research, published online in “The Lancet” on this week, suggests that babies born to overweight mothers in sub-Saharan Africa are significantly more likely to die in the first two days after their birth. The report, thought to be the first study of its kind about the developing world, suggests that growing obesity will put future pressure on the continent’s already-high death rates among newborns.

According to estimates, a quarter of adults in sub-Saharan Africa will be overweight by 2030 -- a striking projection for a continent where we are more used to seeing images of skeletal children struck by famine.

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The most significant causes might be the side-effects of urbanization. Millions of people who once grew their own food are being drawn toward Africa's super-cities, where they are more likely to rely on street hawkers and urban supermarkets. Around one-third of Africa's 1 billion people live in an urban area, but in 20 years around half of Africans will.

The problem certainly isn’t fast food alone, but fast-growing cities, built upon fast-growing economies that are reshaping many African societies as well as reshaping many of their people.

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