Study Links India's Green Revolution to Increased Diabetes Risk

Dietary habits changed in favour of more carbohydrate dense foods – wheat and rice – at the expense of more protein rich foods.

Faithful friends of this newsletter will know that it tends to favour certain topics. India’s green revolution is perhaps top of the list. 

So, when my friend, Karan Singhal – one of the brightest young scholars from India –, pointed me to a new study about India’s green revolution, I began to spin with excitement, like this person below, but lacking somewhat in elegance and charm. 

What does it reveal? 

The study by economists Sheetal Sekhri and Gauri Kartini Shastry examines the long-term health impacts of India's Green Revolution, which brought in new high-yielding varieties of wheat and rice. It finds that the green revolution contributed to an increase in chronic diseases – diabetes, and to a lesser extent, heart disease and high blood pressure. 

How did the researchers uncover this link? They took advantage of the fact that the new crop varieties required reliable and a lot of irrigation to be successful, as other researchers have also observed. This meant adoption happened faster in areas with abundant groundwater, primarily through tube wells.(In fact, tube wells were so vital for the green revolution that the Economist Robert Repetto said that we might as well call it the tube well revolution)

By comparing health outcomes for people born just before and after 1966 (when the Green Revolution began) in districts with different groundwater levels, Sekhri and Shastry could isolate the impact of early-life exposure to the agricultural changes.

The results are striking - men born after 1966 in groundwater-rich districts (meaning green revolution districts) have about a 4 percentage point higher rate of diabetes compared to those born before 1966. This represents a large increase given that the overall diabetes rate for older men in the sample was around 26%.

There are other studies, which Sekhri and Shastry point to, that have found that a low-protein pre-natal diet can lead to high blood pressure and glucose intolerance in rats and mice. 

Importantly, the researchers don't find similar effects for “non-diet-related chronic diseases, such as cancer, asthma, and tuberculosis”. (Although, there is evidence that shows that the green revolution led to a higher incidence of cancer too in some parts. But that was because of the use of pesticides and not diet related). This suggests the impact is specifically tied to nutritional changes brought about by the Green Revolution.

How did this happen? The green revolution changed crop growing patterns in certain parts of India to more carbohydrate dense crops – wheat and rice – at the expense of some protein rich crops, like pulses. The increased availability of these crops also changed dietary habits. So, Indians in green revolution regions began consuming more of wheat and rice, at the expense, again, of pulses and other more nutritious foods. 

Crucially, they find that the prevalence of diabetes is more pronounced in households that predominantly eat rice compared to those who prefer wheat. This can be directly linked to the nutritional profile of rice. Compared to wheat, rice has approximately half the protein content, more carbohydrates, and a higher glycemic index. 

The paper also finds that the incidence of chronic diseases has increased only among men. It doesn't find similar evidence for women, which, according to Sekhri and Shastry, could be because of data limitations or because of gender disparities in how food is consumed in a household. 

It's not a secret that in many Indian families, women only eat after the men have eaten. Often, what they eat is also different. For example, women are more likely to be vegetarian than men in India.

The Green Revolution achieved calorie adequacy but compromised nutritional diversity

The paper acknowledges that the green revolution played a vital role in addressing the acute problem of calorie deficiency India faced at the time. But, it does posit, that it is likely that those gains were offset by the increase in chronic diseases.

Let’s also not forget that back in the 1960s, India faced a severe hunger challenge (one that hasn’t entirely gone away, by the way) and even famines.

The people behind India’s green revolution had one thing in mind, and that was to make India food self-sufficient, which in the 1960s more or less meant calorie self-sufficient.

So, the green revolution’s grand overarching focus was on growing more of wheat and rice using the newly developed high-yielding seeds. That came at the expense of other crops, which meant that crop diversity and therefore, dietary diversity stood diminished.

In India’s primary green revolution regions of Punjab and Haryana, there was greater crop diversity before 1965. In the early 1960s, 39% of the crop area belonged to wheat and rice. Now, it is nearly 85%. 

The other important crops grown in the region included pulses, oilseeds, maize, sugarcane, bajra (pearl millet), barley, and cotton. 

In fact, some of these crops are part of Punjabi folklore. There are several popular Punjabi folk songs about bajra, for instance. But, now the production of Bajra in Punjab is almost negligible.

So, Sekhri and Shastry, argue that their work has implications for India’s subsidised food delivery programme (the Public Distribution System). Currently, it “promotes a high-calorie, low-protein diet by prioritizing the distribution of wheat, rice, sugar, and kerosene.”

There have been many efforts to include more protein rich foods, like pulses, in the mix. But they have, by and large, failed.

The fundamental issue perhaps is that India today grows too much of wheat and rice. And that impacts India’s economy, its politics, its air pollution levels, its nutritional outcomes and more. But, that’s another story for another time.