Increasing reliance a short list of major food crops like wheat, maize and soybean – along with meat and dairy products – is limiting diversity and increasing the risk of global food crises, a global ag research group said earlier this month.
While the selected food groups offer more food for hungry populations, the new study of global food supplies conducted by CGIAR shows that over the last 50 years, human diets around the world have grown more similar by a global average of 36%. The trend is not slowing, researchers say.
"More people are consuming more calories, protein and fat, and they rely increasingly on a short list of major food crops," said lead author Colin Khoury, a scientist at the Colombia-based International Center for Tropical Agriculture.
Khoury explains the implications a limited diet can have on diversity. "These foods are critical for combating world hunger, but relying on a global diet of such limited diversity obligates us to bolster the nutritional quality of the major crops, as consumption of other nutritious grains and vegetables declines."
Published in the Proceedings of the National Academy of Sciences of the United States of America, the study suggests that growing reliance on a few food crops may also accelerate the worldwide rise in obesity, heart disease and diabetes.
To put everything in perspective, common crops like wheat, rice, maize and potato are major diet staples; wheat, for example, is a major staple in 97.4% of countries and rice in 90.8%. Soybean has become significant to 74.3% of countries.
In contrast, many crops of regional importance—including sorghum, millets and rye, as well as root crops such as sweet potato, cassava and yam—have lost ground, the study finds.
Many other locally significant grain and vegetable crops—for which globally comparable data are not available—have suffered the same fate. For example, a nutritious tuber crop known as Oca, once grown widely in the Andean highlands, has declined significantly in this region both in cultivation and consumption, the study found.
Questions of vulnerability
"Another danger of a more homogeneous global food basket is that it makes agriculture more vulnerable to major threats like drought, insect pests and diseases," Luigi Guarino, a study co-author and senior scientist at the Global Crop Diversity Trust, explained in a statement.
"As the global population rises and the pressure increases on our global food system, so does our dependence on the global crops and production systems that feed us. The price of failure of any of these crops will become very high," he added.
As the authors probed current trends in food consumption, they found that increasing homogeneity on the global level wasn't apparent in some African and Asian countries, where the menu major staple crops has widened.
"In East and Southeast Asia, several major foods—like wheat and potato—have gained importance alongside longstanding staples, like rice," Khoury noted. "But this expansion of major staple foods has come at the expense of the many diverse minor foods that used to figure importantly in people's diets."
Rising incomes in developing countries can drive dietary changes, study authors explain, enabling more animal product, oil and sugar consumption. Urbanization also has encouraged greater consumption of processed and fast foods.
Related developments, including trade liberalization, improved commodity transport, multinational food industries, and food safety standardization have further reinforced these trends, the study says.
"Countries experiencing rapid dietary change are also quickly seeing rises in the associated diseases of overabundance," said Khoury. "But hopeful trends are also apparent, as in Northern Europe, where evidence suggests that consumers are tending to buy more cereals and vegetables and less meat, oil and sugar."
The researchers single out five actions that are needed to foster diversity in food production and consumption and thus improve nutrition and food security:
• Promote adoption of a wider range of varieties of the major crops worldwide. This could boost genetic diversity, reducing the vulnerability of the global food system.
• Support the conservation and use of diverse plant genetic resources
• Enhance the nutritional quality of the major crops through crop breeding; make supplementary vitamins and other nutrient sources more widely available.
• Promote alternative crops that can boost the resilience of farming and make human diets healthier through research aimed at making these crops more competitive in markets.
• Foster public awareness of the need for healthier diets, based on better decisions about what and how much we eat as well as the forms in which we consume food.
Read the complete study, "Increasing homogeneity in global food supplies and the implications for food security."