Nutrition Shock: How an Abundance of Food Can Lead to an Increase in Chronic Disease

April 18, 2019
A wheat field in India
Credit:
Gurminder Singh/Hindustan Times via Getty Images

Facing the threat of famine in 1966, India revamped its agricultural system, increasing its rice and wheat crops in what is known as the Green Revolution. Among other changes, these high-calorie, low-protein foods became more available to India's population.

Through their research of the Green Revolution, Gauri Kartini Shastry, Wellesley associate professor of economics, and her colleague Sheetal Sekhri, associate professor of economics at the University of Virginia, have identified a connection between the sudden abundance of food grain products in environments with widespread poverty and the prevalence of chronic diseases like diabetes and heart disease.

A draft of their research, which is based largely on surveys and historical data, traces a timeline that begins in 1947, when India won its independence. In 1966, concerns about stagnant food production and India’s reliance on food being imported from other countries prompted the government to experiment with a variety of rice grown in the Philippines and wheat from Mexico.

States with ample groundwater—Punjab, West Bengal, and Tamil Nadu—became heavy producers of these new crops because farmers were better able to irrigate them. High doses of fertilizer also played a role, helping production of rice and wheat increase by as much as 20 times in the first five years.

India’s government believed that the introduction of new foods could reduce hunger and certain types of malnutrition. But the revolution also had an unanticipated negative effect. In the India Human Development Survey of 41,554 households, Shastry and Sekhri find an increase in the incidence of chronic diseases, such as diabetes and heart disease, among men born after 1966 in those areas with more available groundwater.

Most other channels through which the Green Revolution could have impacted long-term health—such as the increase in income or the reduction in hunger and associated anxiety—would predict a positive long-term impact. One possible explanation for the adverse effect is that the Green Revolution also produced what Shastry and Sekhri call a “nutrition shock.”

Large segments of the population, particularly families with children, may have increased their consumption of rice and wheat-based products, which became more abundant, rather than foods enriched with protein and other vital nutrients. When the children of these families grew into adulthood, they continued their nutritionally deficient diets. Their eating habits became a lifestyle that had long-term health consequences.

“What you eat as a child creates habits and so it’s very likely that changes in eating habits as a child persisted until a person is older,” Shastry says. “It’s quite possible that a person’s diet in early childhood has long-term effects.”

Other strong factors also influenced eating habits. More nutritious protein-based foods are more expensive compared to foods made with rice and wheat. Farmers also grew more of these staples because of both increased profits and wholesale changes in agricultural practices to cultivate rice and wheat, which increased their supply and demand.

Shastry and Sekhri find support for this explanation in the National Sample Survey Organization’s Household Consumption Expenditure data from 1983. Data from that survey revealed to Shastry and Sekhri that households with men born after 1966 in groundwater-rich areas tended to eat more calories and fat rather than protein-rich food.

Women, meanwhile, did not experience the same increased rates of disease. Shastry and Sekhri found no definitive answers for this gender differential, but Shastry offered several possible explanations. “It could be because these diseases show up in women later than they show up in men, so it’s still too soon to see the impacts for women,” she said.

A second possible reason could be the fact that women did not change their dietary habits as much as men, and a third reason relates to activity levels. “If men are performing more manual labor, they may be eating more rice and wheat when it becomes plentiful,” said Shastry.

Overall, Shastry and Sekhri believe that developing countries should take changes in diet and their long-lasting effects into account when introducing new policies that impact food production and distribution.

Photo: A farmer harvests wheat crop in Ludhiana, a large industrial city in the north Indian state of Punjab, in April 2017.