Increasingly homogenized ‘global food basket’ putting crops, human health at risk

We must adopt a wider range of varieties of the major crops worldwide to boost genetic diversity.

Globalization has helped increase local supplies of energy-dense food crops, but at a significant cost to global food security and human health, according to a new study by the University of British Columbia, the International Center for Tropical Agriculture, and the Global Crop Diversity Trust.

The comprehensive study of global food supplies thoroughly documents for the first time what experts have long suspected—over the last five decades, human diets around the world have grown increasingly similar by an average of 36 percent.

The trend has the potential to boost obesity, heart disease and diabetes rates, and places food production at increased widespread risk to drought, insect pests and diseases. Published Monday in the Proceedings of the National Academy of Sciences, the study calls for urgent efforts to better inform consumers about diet-related diseases and to promote healthier, more diverse food alternatives.

"These results indicate a need to re-invest in the breeding of the many minor crops that are being lost from local and regional diets," says study author Loren Rieseberg, Canada Research Chair in Plant Evolutionary Genomics and a professor with the UBC Department of Botany. "Making such crops competitive through increased productivity may represent the most effective long-term strategy for their continuity." The emerging 'standard global food supply' described by the study include several crops that were already staples a half-century ago—such as wheat, rice, maize and potato–as well as more energy-dense foods that have risen to global prominence more recently, like soybean, sunflower oil and palm oil. Wheat is a major staple in 97.4 percent of countries and rice in 90.8 percent. Soybean has become significant to 74.3 percent of countries. In contrast, many crops of considerable regional importance—sorghum, millets, rye, sweet potato, cassava and yam—have lost ground.

"More people are consuming more calories, protein and fat, and they rely increasingly on a short list of major food crops, like wheat, maize and soybean, along with meat and dairy products, for most of their food," says the study’s lead author Colin Khoury at the Colombia-based CIAT.

"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."

Key Recommendations

  • Promote the adoption of a wider range of varieties of the major crops worldwide to boost genetic diversity and thus reduce the vulnerability of the global food system in the face of challenges that include climate change, rising food demand, and increased water and land scarcity. This action is especially important for certain crops, like banana, for which production is dominated by a very few, widely grown commercial varieties.
  • Support the conservation and use of diverse plant genetic resources—including farmers’ traditional varieties and wild species related to crops—which are critical for broadening the genetic diversity of the major crops. More vigorous implementation of the International Treaty on Plant Genetic Resources for Food and Agriculture is required to better safeguard and share these genetic resources internationally, and increased investment in crop research.
  • Enhance the nutritional quality of the major crops on which people depend—for example, through crop breeding to improve the content of micronutrients like iron and zinc—and make supplementary vitamins and other nutrient sources more widely available.
  • 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.


The study relies on data from the Food and Agriculture Organization of the United Nations, encompassed more than 50 crops and over 150 countries (accounting for 98 percent of the world’s population) from 1961 to 2009. In addition to CIAT, GCDT and UBC researchers, it involved researchers from Wageningen University in the Netherlands.

PNAS Article

Increasing homogeneity in global food supplies and the implications for food security


Loren Rieseberg University of British Columbia

Colin Khoury International Center for Tropical Agriculture +57 445 0000 x3555 +57 310 899 5865 (cell)



"These results indicate a need to re-invest in the breeding of the many minor crops that are being lost from local and regional diets."

Chris Balma
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