Heart disease, now considered an affliction of the wealthy Western world, is going to be a top killer soon in the developing world, researchers predicted on Monday.

Data from 100 countries on weight, diet, cholesterol, blood pressure and other factors important in Heart disease show the developing world is clearly on course to become as overweight and out of shape as many industrialized countries, they found.

Just as in the United States, Britain and other developed countries, heart disease will become the No. 1 killer in poorer nations, Majid Ezzati and colleagues at the Harvard School of Public Health predicted.

“cardiovascular disease risks are expected to systematically shift to low-income and middle-income countries and, together with the persistent burden of infectious diseases, further increase global health inequalities,” they write in this week’s issue of the Public Library of Science, Medicine.

“Preventing Obesity should be a priority from early stages of economic development, accompanied by population-level and personal interventions for blood pressure and cholesterol.”

Ezzati’s team looked at body mass index, a globally accepted measure of height to weight. People are considered overweight with a BMI of 25 and obese when BMI reaches 30. Obesity carries a clearly higher risk of heart disease, Diabetes and some cancers.

“We examined the cross-sectional relationship between mean population blood pressure, cholesterol, and body mass index and three socioeconomic variables: national income, average share of household expenditure spent on food, and proportion of population in urban areas,” they wrote.

As income went up, usually the proportion of household income spent on food went down, the researchers found. And cheaper food almost always meant expanding waistlines and higher cholesterol.

But the growth in BMI and cholesterol peaked at a certain income level, they also found, and then leveled off.

As the proportion of people living in cities increased, so did BMI and cholesterol, they found.

World Health Organization data show that developing nations are moving quickly to a Western-style diet high in fat and salt.

And people exercise less as transportation and technology improve.

“If a similar upward shift in the income-BMI relationship occurs globally, overweight and obesity will play an even larger role in disease burden in developing countries, because these countries will be on an even higher income trajectory,” the researchers cautioned.