A fertiliser subsidy is not usually considered part of national health policy.
As pulses receded from Indian fields and plates, we lost one of our cheapest, most climate-friendly sources of protein. Perhaps it should be. Consider pulses. Consider a family of four that gets all its protein from dal. It’s little wonder that dal anchored everyday protein, while meat was reserved for special occasions. The climate logic is even more compelling. Mesfin Mekonnen and Arjen Hoekstra were both researchers at University of Twente in the Netherlands when they came up with the idea of a water footprint (the total water used to raise a crop or rear an animal, and to grow its feed). We see the impact in the falling water levels in India’s underground aquifers. PROTEIN FLEX Dal, meanwhile, is so climate-friendly that research by Joseph Poore of Oxford university and Thomas Nemecek of the Swiss research institute Agroscope found that any substitute, including rice, emits more greenhouse gases. Most substitutes, plant and animal, use more land to grow. And while the excess fertiliser used to grow animal feed washes into rivers and lakes, pulses make their own nitrogen. But averages can be misleading. Those who regularly eat polished rice get much less.
In the late 1970s, rural Indians ate about 34 gm of pulses a day. By 2023-24, this had fallen to 25 to 27 gm a day, or about half a small bowl of cooked dal. Based on current retail prices, switching to eggs would cost them ₹ 33,000 more a year (though eggs, to be fair, offer a more complete protein). Switching to mutton would cost ₹ 4.36 lakh more (chicken and beef / buffalo meat lie somewhere in-between). In Indian conditions, our family would use 22 lakh litres more a year if they switched to eggs, and 80 lakh litres more for beef / buffalo meat. Indian adults get roughly 33 gm of fibre a day, down from about 42 gm a day in the late 1970s. Women typically get less; one study of 440 women found they get about 20 gm a day. Vulnerable urban communities get under 10 gm. Nor does it appear in the 2023-24 Household Consumption Expenditure Survey (HCES), another source of information on nutrition.
Because cheap urea, alongside cheaper irrigation and guaranteed procurement, changed what India ate, with consequences for our collective health. Because that water is subsidised, the price of the food item doesn’t reflect how much of this resource has gone into it. Because none, repeat, none, of the animal options offers a single gramme of dietary fibre, pulses are an extraordinary source of protein. Because nobody was looking, yet nobody raised the alarm, possibly.
The number keeps falling as we trade in whole wheat for maida, and forsake our “coarse” cereals (thank you, water and fertiliser subsidies). The National Nutrition Monitoring Bureau exists to track what Indians eat, but the word “fibre” appears nowhere in its survey reports for 1996-97, 2011-12 or 2015-17 (urban), nor in its 25-year review.
For a molecule with an unimaginative name, it produces that holy grail of weight loss, GLP-1 (or Glucagon-like Peptide-1), in response to signals such as glucose. In another experiment, they found mice without the lock produced far less GLP-1 and less insulin, and handled glucose poorly. GLP-1 also has cardiovascular and neuroprotective benefits. A WEAK PULSE It isn’t just GLP-1. Zhao Liping, a microbiologist at Shanghai Jiao Tong University and Rutgers University, took people with Type 2 diabetes and randomly assigned them one of two calorie-matched diets. One group followed standard dietary advice, while the other adopted a meal plan especially rich in diverse fermentable fibres. (Both groups also received the anti-diabetes drug Acarbose.) Over 12 weeks, the researchers then examined the participants’ faeces, to see if their gut bacteria reflected a change. A recent study published in Nature Medicine placed the potential economic cost of diabetes for India at $11.4 trillion between 2020 and 2050.
Because with every mouthful of fermentable fibre, the kind that pulses are rich in, we feed the trillions of bacteria in our guts, this is a tragedy,. In their experiment, they used mice genetically engineered so that their L-cells glowed yellow under a microscope. THE FIBRE FACTOR We haven’t noticed fibre slipping out of our diets. They, in turn, produce compounds that can influence how we handle glucose, regulate inflammation and respond to stress. Given India’s diabetic epidemic and the Indian body’s unique inability to cope with dietary excess, let’s take a minute to delve deeper into how the gut microbiome helps us handle glucose. Scattered throughout the gut’s single-cell barrier is a type of cell called the L cell. Paradoxically, the greatest concentration of L-cells is found in the colon, where very little glucose reaches. Why is that? Did the body get something wrong? Researcher Gwen Tolhurst and her colleagues at University of Cambridge set out to answer that question and found that the body had not, in fact, got things wrong. The researchers removed cells from the mice’s colon and grew those in the lab. They then used the yellow glow to pick out the L-cells, and added short-chain fatty acids — the compounds made when gut bacteria ferment dietary fibre — to the mix. These benefits are what we forego when we lose fibre in our diets. L-cells send out an entire symphony of messages; not a single, loud, jarringly persistent note like the one some weight-loss drugs produce. But is there good evidence that fibre reshapes the human gut? Change it did. The scientists found that the high-fibre diet promoted bacteria capable of producing short-chain fatty acids, and that participants on this diet achieved better control over their blood-sugar levels. Participants with a greater abundance of these fibre-responsive bacteria saw more improvement in their HbA1c levels, a longer-term measure of blood glucose. Fibre was reshaping the gut microbial ecosystem and, as that ecosystem changed, the body began to handle glucose better. Which brings us back to the Indian plate. Dietary fibre has been overtaken by alternative foods, in part as a direct fallout of water and fertiliser subsidies. The falling importance of pulses on our plate is the canary in the coal mine. The song it sings, deep within our gut, is playing out in the metabolic crisis in India. In budgeting for the subsidies, we do ourselves no favours by leaving out the health or climate costs. Our siloed approach to policymaking is at least partly to blame. Food, agriculture, the environment, nutrition and metabolic disease were never separate concerns. They are deeply interconnected. In order to move forward, we need to see them that way. (Mridula Ramesh is a climate-tech investor and author of The Climate Solution and Watershed. She can be reached on [email protected]. The views expressed are personal)
The Indian Council of Medical Research (ICMR)-National Institute of Nutrition’s What India Eats report mentions fibre just once, in passing, assuring readers that complex carbohydrates “will also satisfy the fiber requirements”. The L-cells released a lot of GLP-1 at this point because, as further experimentation showed, they have a special biochemical “lock” that metabolites such as short chain fatty acids unlocked. L-cells in the colon release a whole host of chemicals, including other peptides, that tell the body: “I’m full, stop eating”.
