A new research has found that the affordability of more nutritious foods is an important factor when it comes to factors likes malnutrition, obesity and child stunting.

As part of the latest study, researchers at the International Food Policy Research Institute (IFPRI) say, affordability of both healthy and unhealthy foods varies significantly and systematically around the world. The study also suggested that these relative price differences help explain international differences in dietary patterns, child stunting and overweight prevalence among adults.

Past research has only studied relative price differences in specific countries, mostly in the context of the relative cheapness of calorie-dense processed foods as a risk factor for obesity in upper- and middle-income countries.

“Our research shows that most healthy foods are substantially more expensive in poorer countries,” says IFPRI Senior Research Fellow and study co-author Derek Headey.

According to the study, higher caloric prices of a food predict lower consumption of that food and explores how those price differences might explain international differences in child stunting and adult obesity.

Published in ‘The Journal of Nutrition’, the study found that the relative caloric prices of healthy and unhealthy foods differ systematically across income levels and continents.

In the world’s poorest countries, healthy foods were often extremely expensive, especially nutrient-dense animal sourced foods, which are widely known to be effective in reducing stunting.

“Prior to this study, we already knew that the poorest children in the world weren’t consuming enough of the really nutrient-dense foods that promote healthy growth and brain development”, said Headey. “But now we have a better idea why: poor people also live in poor food systems. That combination of low incomes and high prices means they’re simply not going to buy enough and eat enough of these nutrient-dense foods.”

While poor child feeding practices are often attributed to limited nutritional knowledge in low income settings, the authors found that the high prices of nutrient-dense foods offered an alternative explanation of their low consumption. Even more strikingly, they find that higher prices of milk, eggs and fortified infant cereals predict higher rates of stunting. “The link between milk prices and stunting is especially strong which is entirely consistent with a whole body of evidence on the strong linkages between dairy consumption and child growth,” said co-author Harold Alderman.

Headey and Alderman found that lower prices of soft drinks and sugar-rich snacks predict significant increases in overweight prevalence among adult populations. Alderman said, “Public health agencies in upper income countries have been concerned with the high consumption of sugar-rich foods for some time,but our study shows that these products often become very affordable in middle income countries, and sometimes even in relatively poor countries where obesity rates are really on the rise.”

Headey said, “These findings raise an important agenda for future research: understanding why food prices vary across countries, and sometimes within them, and how best to change food prices in a way that leads to better diets and nutrition outcomes in rich and poor countries alike.”