Impact of dietary shifts in India on greenhouse gas emissions, land use, water use, and food expenditure: a nationally-representative study

Abstract

Background: Food production is a major driver of environmental change, while dietary risks are the leading cause of global disease burden. Studies suggest that adoption of healthy diets in high-income countries can provide environmental co-benefits. However, little is known about such options in low and middle-income countries. India is home to one-fifth of the global population, and experiencing complex nutritional challenges, alongside critical environmental pressures on its ability to produce food. This project assesses the potential for dietary change to improve health and diet-related environmental footprints in India. Methods and results: A systematic review assessed the sustainable dietary patterns studied in the literature, and their impacts on a range of environmental indicators, to understand which diets may lead to improved environmental and health outcomes. Adoption of sustainable diets is generally estimated to reduce environmental footprints, though large variations in reductions are seen across sustainable diet types. Following national dietary guidelines may be a relevant public health goal with both environmental and health benefits. A comparison was undertaken of a number of dietary intake data sources in India, examining relative differences in overall intake, and intake of key food groups, to better understand data suitability for sustainable diet analyses. The comparison highlighted the 2011-2012 National Sample Survey (NSS) household expenditure surveys as a relevant data source for the project, though data sources showed high variability in intake, particularly for a set of key nutrient-dense food groups. The NSS and environmental footprint data were matched to estimate the change in greenhouse gas (GHG) emissions, land use (LU), and water footprints (WFs) that may result from national adoption of healthy dietary guidelines, and contrasted this with a scenario of widespread uptake of “affluent” diets. A shift to healthy guidelines in India would result in a small increase in environmental footprints (4-5% for GHG emissions, LU and WFs), though this national result masked large variations among sub-samples; for example, healthy diet shifts among those who consume above recommended dietary energy could decrease emissions by 6-16% across the three environmental indicators. Shifts to affluent diets would result in large increases of about 19-36% across indicators. Lastly, differences in cost were assessed between observed healthy and lowerfootprint diets, and average diets with sufficient dietary energy (“adequate” diets). Overall, healthy diets with lower footprints were slightly more expensive than an adequate diet. Large variations were observed among sub-samples of the population: improved diets were particularly more expensive for lower-income individuals and rural residents, while cheaper, or had no difference in price, for individuals in the highest quartile of socioeconomic status, and for urban residents. Higher expenditure on improved diets was particularly associated with fruit and vegetables, and dairy. Conclusions: Achieving the critical public health goal of healthy diets while minimising diet-related environmental footprints in India may require three broad strategies: increasing the efficiency of agricultural production, alongside efforts to improve the affordability of healthy dietary change, and the active promotion of healthy and lower-footprint diets for those who can currently afford them.