Over the past half-century, something kind of amazing has happened. Serious malnutrition has declined enormously in much of the world as new agricultural technologies and increased international trade have given us much more to eat. But, at the same time, formerly “first-world” diseases like diabetes and heart disease that are associated with unhealthy eating are becoming a bigger issue across the globe. In a 2010 paper, biologist John Kearney crunched the numbers.

Looking at the food people have available to them (which tends to be a bit more than they actually eat), Kearney found that in 1970 the world’s people got an average of 2411 calories a day. By 2000, that was up to 2789. The change in the developing world was even more dramatic, rising from 2111 to 2654.

There are still some big gaps in this growth. In particular, sub-Saharan Africa’s available food only added up to 2194 calories a day in 2000. But projections for the next decades suggest continuing increases in every part of the world. In 2050, they show per-capita calories in sub-Saharan Africa hitting 2830 per day, even as it continues to be the region with the least food.

Meanwhile, the sources of the calories we eat have changed too. Between 1963 and 2003, per-capita consumption of meat and sugar more than doubled in the developing world, and the use of vegetable oils rose 199 percent. In China, the increase was even more dramatic: more than 300 percent for meat and sugar, and 680 percent for vegetable oils.

China and other “emerging markets” like Mexico and Brazil are the poster children for “nutrition transition”—the shift away from under-nutrition and toward obesity and diseases related to high levels of fat, sugar, and salt consumption. This is related not just to new availability of meat, sugar, and oil but to urbanization, which encourages reduced physical activity and more purchases of mass-marketed food. Trade liberalization and the growth of transnational brands like McDonalds and Kraft have also contributed to lifestyle-related health problems.

Adult-onset diabetes has been on the rise in South Asia. By 2025, projections suggest three in four diabetic patients will come from developing countries, and a fifth will be in India alone.

In China more than 20 percent of adults were obese around 2009. In rapidly developing countries (as in the U.S.), obesity and related problems are particularly common among the poor, who also face problems of under-nutrition. In these populations, many people get too many total calories but not enough of some key nutrients.

To address the changing nutritional needs of the world, Kearney suggests agricultural development needs to change course. Instead of focusing on simply producing more calories, the world’s farmers must concentrate on the growth of fruits, vegetables, legumes, and animal products. He writes that agricultural policies also should encourage local self-reliant food policies that take health and environmental concerns into account, rather than leaving the world’s nutrition in the hands of transnational companies.