Subsidies for the big crops also neglect the need to promote healthy diets. Take wheat, for example. Whole unrefined wheat is a major source of starch and energy, as well as protein, vitamins (notably B vitamins), dietary fibre and phytochemicals.

Loading

But demand for wheat has been rising globally because of its unique gluten properties, which make it also an ideal component of bread, noodles, pasta, cookies, crackers and many other baked foods and snacks. These highly processed foods, which now constitute a significant share of the world’s diet, are depleted of healthy nutrients and contribute to poor health.

Over the past 50 years, farm subsidies, supported by complementary research and development efforts in agriculture-dependent countries, have made rice, corn and wheat the world’s most dominant crops, accounting for two-thirds of global food-energy intake. Alternative staples such as sorghum, millet, rye, cassavas, sweet potatoes and yams haven’t disappeared — at least not yet — but they have become steadily less important.

To encourage a more diverse and resilient food supply, countries should begin reorienting agriculture subsidies toward fruits, vegetables, nuts and legumes and other nutritious foods. A recent study suggests that if half of all agriculture subsidies worldwide were repurposed to support the growing of foods that benefit human health as well as the environment, it could increase the cultivation of fruits and vegetables by as much as 20 per cent and reduce greenhouse-gas emissions from agriculture by 2 per cent.

Shifting agriculture subsidies is no easy lift. Many farmers depend on them to support their livelihoods, and many would consider it incredibly risky to make major changes in what they grow.

Loading

But with climate change increasing and geopolitics unstable, change is becoming more and more necessary. And if people are to avoid chronic health problems such as diabetes and heart disease, they need assistance from the food system to adopt more nutritious diets.

The global disruption caused by the war in Ukraine should prompt governments to reconsider their efforts to influence the crops farmers grow and move toward encouraging a more diverse food supply.

Jessica Fanzo is a Bloomberg Distinguished Professor of global food and agricultural policy and ethics at the Nitze School of Advanced International Studies, the Berman Institute of Bioethics and the Department of International Health of the Bloomberg School of Public Health at Johns Hopkins University.