Many low- to middle-income countries struggle with issues of undernutrition. Around a third of them, however, are faced with a very unusual problem: undernutrition and obesity at the same time.

Obesity and undernutrition have become increasingly connected in recent decades, a new paper reports. It explains that modern food systems are negatively impacting the health of poorer countries around the world, with the poorest being particularly affected. The authors also look at the causes, context, and possible solutions to this issue.

The faults in our food

“We are facing a new nutrition reality where major food system changes have led the poorest countries to have high levels of overweight and obesity along with undernutrition,” says Barry M. Popkin, lead author of the paper and W.R. Kenan Jr. Distinguished Professor of Nutrition at the University of North Carolina.

“Our research shows that overweight and obesity levels of at least 20% among adults are found in all low-income countries. Furthermore, the double burden of high levels of both undernutrition and overweight occurs primarily in the lowest-income countries — a reality that is driven by the modern food system. This system has a global reach and is preventing low- and even moderate-income countries and households from consuming safe, affordable, and healthy diets in a sustainable way.”

Global estimates place the total number of obese children and adults in the world at some 2.3 billion, the paper explains. It’s just one half of the issue known as the double burden of malnutrition — the other being undernutrition, a deficiency of calories or (in this context) essential nutrients.

For the study, the team used survey data from low- and middle-income countries in the 1990s and 2010s to estimate which of them were experiencing the double burden of malnutrition. If over 15% of a country’s population had wasting and over 30% stunting, over 20% of its women show thinness, and over 20% of its citizens in total were overweight, the team considered that particular country to be experiencing this double burden.

Over a third of low- and middle-income countries satisfy this condition — 45 of 123 countries in the 1990s and 48 of 126 countries in the 2010s — meaning they’re experiencing both forms of malnutrition. It was most commonly seen in sub-Saharan Africa, East Asia and the Pacific, and South Asia where 29, 9, and 7 countries were affected, respectively. In the 2010s, 14 more countries (with some of the lowest incomes in the world) had started to experience this double burden of malnutrition compared to the 1990s.

In comparison, low- and middle-income countries that enjoy the highest incomes in the category were much less likely to experience this issue, the team adds. In their view, this is indicative of a growing number of overweight people in the poorest countries even as large segments of the population face stunting, wasting, and thinness.

“Emerging malnutrition issues are a stark indicator of the people who are not protected from the factors that drive poor diets,” Popkin says. “The poorest low- and middle-income countries are seeing a rapid transformation in the way people eat, drink, and move at work, home, in transport, and in leisure.”

“The new nutrition reality is driven by changes to the food system, which have increased the global availability of ultra-processed foods that are linked to weight gain while also adversely affecting infant and preschooler diets. These changes include disappearing fresh food markets, increasing numbers of supermarkets, and the control of the food chain by supermarkets and global food, catering, and agriculture companies in many countries.”

But how can someone be both underfed and overfed at the same time? It comes down to the quality of food they can access. Ultra-processed foods are a very attractive option for people with low incomes, as they’re convenient (they require very little time investment to prepare), they seem hearty and are widely available. However, while they usually pack a caloric punch, they’re very poor in nutrients; in essence, they’re empty calories. Even worse, they usually contain a high level of additives to make them more appealing and to increase shelf-life, which can have adverse effects on health and body mass.

In an ironic twist of fate, healthy options such as fresh vegetables can be effectively out of reach for people with low incomes who may not have the purchasing power or time necessary to acquire and prepare them, or simply haven’t been educated on the drawbacks of their current diet.

The authors recommend “double-duty” policies aimed at reducing both the risk of nutritional deficiency and that of obesity and its related effects. They call for a concentrated effort from local governments, civil society, academia, the private sector, and the United Nations to create the economic conditions needed to address the double burden of malnutrition to devise and implement such strategies.

We also shouldn’t make the error of believing this issue is limited solely to ‘someplace else’. Previous research has highlighted that over half of America’s calories come from ultra-processed foods, and that they are responsible for 90% of the total added sugar intake in the country.

The paper “Dynamics of the double burden of malnutrition and the changing nutrition reality” has been published in the journal The Lancet.