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Water footprint of our diet and ways to reduce it

Edition: April-June 2020

When we talk of food, the focus usually is on how nutritious/tasty/pricey it is, and seldom on how the food has been produced. Modern food production is an exploitatory industry established on the back of fossil fuels, chemical fertilisers, farmer exploitation, and water overuse. India is both a water scarce and an agrarian country, and therefore it makes sense to look into how much of a water footprint our food production has. Here we discuss water consumption of a typical Indian diet, different sources which provide this water for food production, and how we can reduce it.

Water footprint (WF) is an indicator metric that measures the amount of water consumed, evaporated and polluted. Water measured for this purpose can be green, blue and grey water as defined by the WF network. In brief, blue WF is the amount of surface water and groundwater required to produce an item, while green WF is the amount of rainwater required to produce an item, and grey WF is the amount of freshwater required to dilute wastewater produced as a result of industrial and manufacturing activities. India is the world's largest user of freshwater and irrigation for agriculture is responsible for 90 per cent of India’s freshwater consumption. Spread of irrigation as part of the Green Revolution meant increased groundwater extraction (blue WF) while reducing the dependency on rain (green WF). For instance,  farmers are now able to harvest 2-3 crops per year instead of just one with one annual monsoon. Changes brought about as part of the Green Revolution also lead to loss in genetic diversity of our cereals; some highly nutritive and drought resistant crops sank into oblivion.

Today’s typical Indian diet can be broadly divided into two categories - rice based and wheat based, with other variations in the proportions of meat, fruits and vegetables. Rice based diets have been shown to have a higher green WF, while wheat based diets have a higher blue WF. According to NITI Aayog, India is already facing her worst ever water crisis with 60 crore Indians facing extreme water stress and about two lakh deaths each year due to inadequate access to safe water. Even though it’s the use of green and blue WF for agriculture that stress India’s freshwater availability, in this piece we will consider  the overall water requirement for some common food items that we consume. While looking at each product, we shall also look at the alternative products with a lower WF or modified food behaviour to reduce our WF. 

According to WaterAid India’s Beneath the Surface: The State of the World's Water 2019 report, producing one kilogram (kg) of rice requires about 2,800 litres of water, while a kg of wheat requires 1,654 litres of water. Rice and wheat have a high glycemic index predisposing us to increased risk of diabetes. On the other hand, millets are a diverse set of cereal crops known for their low water requirement, higher nutrient content and low glycemic index. Water requirement of millets is on average 2.5 times lower than that of rice. Millets were once the common cereal for Indians, and we lost them to the Green Revolution, which favoured wheat and rice over other cereals. Researchers have shown that the Green Revolution and the public distribution system (PDS) are together responsible for replacing nutrient rich millets with wheat and rice, which led to a high prevalence of iron deficiency among the Indian population. Examples of millets that were once a common staple of Indian diet are pearl millet {bajra (Hindi)/kambu (Tamil)/sajja (Telugu)/sajje (Kannada)}, finger millet (ragi), sorghum (jowar/cholam/jonna/jola), foxtail millet (kakum/tenai/korra/navane), little millet (kutki/samai/samalu/same) and common millet (chena/pani varagu/variga/baragu). Slowly replacing rice and wheat with millets will go a long way to reducing our dietary WF and will work wonders for the environment and our health. Pledging to consume two millet based meals a week would be a good start.

Fruits, vegetables, and nuts are considered to be healthy and would be least expected to feature in a blog on WF of our diet. There is really no substitute for fruits and vegetables in our diet, but water required for producing 1 kg of the following is: avocados - 834 litres, apples - 822 litres, bananas - 790 litres, mangoes - 686 litres, and plums - 305 litres respectively. As for vegetables, the water required for producing 1 kg of the following is: corn - 486 litres, potatoes - 136 litres, cucumber - 127 litres, cabbage - 109 litres, tomatoes - 100 litres, and lettuce - 68 litres respectively. Producing a kg of groundnut requires 3,100 litres of water. Nuts like almonds, cashews and walnuts collectively need 4,134 litres of water to produce a kg. Add to this the energy and water consumed in storage and transportation, and the only way to lower one’s WF and overall environmental impact of fruits, vegetables, and nuts is to be more mindful in our consumption, opting for local and seasonal produce, and reducing our waste.

Increase in affluence has led to rise in meat consumption in India, putting the country in the  spotlight over how we produce our meat. Water required for producing a kg of each of the following is: beef - 15,415 litres, mutton - 10,412 litres, pork - 5,988 litres, and chicken - 4,325 litres respectively. Meat consumption is an essential source of protein for the many indigenous tribes, the poor, and the historically persecuted groups in India. Per capita meat consumption in India (4 kg/person/year) is significantly lower when compared to that of industrialised nations like the United States of America (124 kg/person/year). Thus, solutions such as a blanket reduction of meat consumption is not required in India. Besides, India does not have an industrial scale of meat production as in other industrialised nations, which is causing them significant environmental concerns. For India, the solution lies in not aping the industrialised nations in meat consumption, but in ensuring a healthy diversity of meat with vegetarian fare.

Processed foods need water not just for production of natural starting ingredients, but for the processing as well, before the finished product is made available to consumers. Producing a kg of chocolate needs a humongous 17,196 litres of water; while water required for each of the following is: butter (pasteurised) - 5,553 litres, cheese - 3,178 litres, pasta (dry) - 1,849 litres, and bread - 1,608 litres respectively. Producing a small pizza (8-10 inches)  requires 1,239 litres of water. Producing a kg of sugar requires 2,000 litres of water and the parent crop of sugarcane has depleted groundwater in many Indian states and each year pushes many farmers to committ suicide in our country. Besides, consuming sugar is a known factor for diabetes, obesity and cardiovascular ailments. Among beverages, water required for making 250 ml of each of the following is: milk (includes water for growing fodder for milch animals and their own consumption) - 255 litres, wine - 109 litres, beer - 74 litres, and tea - 27 litres respectively. None of the processed food items listed above are an essential part of our diet nor do they provide nutrients that are otherwise difficult to obtain from natural products. The question we need to ask ourselves each time we crave for these processed food products is whether it is really justified to dry our planet for our momentary cravings.

For a water and climate resilient India, we urgently need to change the way we eat. We can do this by taking incremental steps and slowly aligning our food production with the local climatic conditions in each state. As warned by the NITI Aayog, our demand for freshwater will outstrip our supply by more than two times by the year 2030, and irrigation for agriculture currently is responsible for 90 per cent of our freshwater demand. In such circumstances, it makes sense to change how we use freshwater and diet plays a very vital role in doing so. Shifting to a diet composed of a variety of cereals with millets forming the bulk, with a healthy mix of fruits, vegetables, nuts, and appropriate source of protein (animal or plant based) might serve well for our own health as well as ensuring our water security. 

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