African doctors say their public health systems have been so focused on AIDS, malaria, tuberculosis and tropical fevers — historically, Africa’s big killers — that few resources are left for what are called noncommunicable diseases, like diabetes and heart ailments.

“What we are seeing is likely the worst epidemic the country will ever see, probably in the long run worse than the H.I.V. epidemic of the ’90s,” said Anders Barasa, a cardiologist in Kenya, referring to obesity and its related diseases. “But changing the health care system to cater for obesity related diseases is like turning a supertanker.”

In Kenya, one of Africa’s most developed nations, there are around 40 cardiologists for the entire population of 48 million people. In the United States, there is one cardiologist for every 13,000 people.

Even as the obesity problem worsens, Africa’s older problem of malnutrition has hardly vanished. While millions of Africans are eating unhealthy foods or overeating, millions of Africans are still starving or near to it.

Last year was one of the worst on record for hunger. In March, United Nations officials warned that famines could break out in three different African countries — Somalia, Nigeria and South Sudan — because of wars and long dry spells.

Full-blown famines have not materialized, because aid agencies got to the hardest hit places quickly enough. But thousands have died from a cholera epidemic catalyzed by malnourished people streaming into camps, and famine still stalks a large part of Africa.