Sustainable Diets, Food, and Nutrition Proceedings of a Workshop (2019) / Chapter Skim
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3 Measurement and Analysis of Sustainable Diets from Production to Consumption
3 Measurement and Analysis of Sustainable Diets from Production to Consumption
Pages 27-52
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From page 27... ...
project to address common challenges to collecting and analyzing dietary data. Because the challenges are similar to those faced when analyzing health systems, he explained, much of what GBD researchers have been doing over the past decade is essentially applying lessons learned about the health system to the food system.
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From page 28... ...
− Reducing per capita meat demand can reduce land loss, drive down meat prices, increase meat consumption in developing countries, re duce feed grain demand, reduce hunger, and reduce GHG emissions. (Rosegrant)
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, data on sales and purchases from Euromonitor, data on household expenditures on food from household budget surveys, dietary consumption data from both 24-hour dietary recalls and food frequency questionnaires, and biomarker data (e.g., to assess daily sodium intake)
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He noted that, because high-quality consumption data were not available, the researchers' dietary estimates in earlier years (before 2000) were informed mainly by FAO food availability data and scattered data from household budget and dietary consumption surveys.
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From page 31... ...
Afshin went on to cite as another challenge that the definition of dietary factors varies across studies. He gave the example of the definition of "whole grain," which varies widely across studies, encompassing different categories of food items (e.g., breakfast cereals, brown rice, brown rice flour, buckwheat, nonwhite bread, and oats in one study, versus added bran, added wheat germ, brown rice, brown rice flour, buckwheat, bulgur, oats, popcorn, and psyllium in another)
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From page 32... ...
He explained that GBD's approach to handling this challenge is to extract data at the food item level wherever such data exist and then use coding to regroup food items as necessary, depending on how the data will be used. Afshin identified serving size as yet another challenge, particularly for food questionnaire data.
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From page 33... ...
Food and Greenhouse Gas Emissions Turning first to GHG emissions, Tilman cited evidence indicating clear differences in contributions to GHG emissions among different foods. He noted that plant-based products, for example, are responsible for relatively low GHG emissions (see Figure 3-2)
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From page 34... ...
"But if people adopted Mediterranean, pescetarian, or vegetarian diets," he argued, "we could have … lower emissions in 2050 from agricultural food production than we have right now from it. Diet can be a big lever." He pointed out, however, that while diet is a big lever, it is not the only lever for addressing sustainable diets, and he then turned to how crops are grown and the precision and efficiency of fertilizer and irrigation.
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From page 35... ...
SOURCES: Presented by David Tilman on August 1, 2018, modified from Tilman and Clark, 2014. Food and Eutrophication According to Tilman, the eutrophication impacts of agriculture, especially nitrogen pollution of surface water, lakes, rivers, and streams, could increase by 70 percent or more over the next 50 years (Tilman et al., 2001)
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From page 36... ...
Another way to visualize the relationship between diet and eutrophication, Tilman continued, is to plot eutrophication impact against the relative risk of health impact. Again, he remarked, for unprocessed foods there is a clear relationship between the two: a linear change in food group– associated health impacts is associated with an exponential change in food group–associated eutrophication impact.
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From page 37... ...
of all mammal and bird species worldwide, Tilman continued, found that the single greatest factor threatening species with extinction is land clearing, particularly land cleared for agriculture. The next-greatest threat, he reported, is logging, most of which is occurring in tropical countries; after being logged, such lands often become pastures or croplands.
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agricultural production on land clearing predicted by Tilman and colleagues (2017) , the extinction risk for large mammals will double in Asia, dramatically increase in sub-Saharan Africa, and increase markedly in South America during this time period.
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and diet-related environmental impacts across four different areas (GHG emissions, eutrophication, use of irrigation water, and land clearing)
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Dietary shifts that prevent land clearing are depicted by upper lightly shaded bars; increased trade of crops from nations with higher yields to nations with lower yields are depicted by middle bars; and dietary shifts that increase yields are depicted by lower darkly shaded bars. SOURCES: Presented by David Tilman on August 1, 2018, modified from Tilman et al., 2017.
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From page 41... ...
. Starting with these definitions, he stated that the objective of his presentation would be to explore what policies, investments, and behavioral changes contribute to improving income, food security, and nutrition while reducing GHG emissions, the use of water and land, and the conversion of forests.
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Evolving Food Demand: Increasing Consumption of Sugar, Fats, Oils, and Meat Rosegrant described the several ways in which food demand is evolving as a result of urbanization and rapid income growth. While diets are changing in some positive ways -- for example, he noted that the consumption of fruits and vegetables is increasing in much of the world -- consumption FIGURE 3-8 (a)
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: Comparing Future Impacts of Different Climate Change, Agricultural Investment, and Meat Demand Scenarios Rosegrant described how, given the above challenges, IFPRI's IMPACT modeling system has been used to examine and compare several different future climate change, agricultural investment, and meat demand scenarios. Without going into great detail, he described IMPACT as a global, multimarket model with a high level of disaggregation, encompassing 159 countries, 154 water basins, and 60 commodities (Robinson et al., 2015)
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Scenarios for More Sustainable and Resilient Food Systems: Investing in Agricultural Efficiency First, Rosegrant described results from modeling three different types of additional investments in the agricultural sector to improve productivity and efficiency: (1) research and development investments to increase productivity, including investments by CGIAR, a global partnership and the main international agricultural research system, as well as investments by the National Agricultural Research System (NARS)
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Scenarios for More Sustainable and Resilient Food Systems: Reduced Meat Demand The IMPACT modeling system was also used to predict future outcomes under different reduced meat demand scenarios, Rosegrant continued. One of these scenarios was a high-income scenario involving a 50 percent reduction in per capita meat demand in all high-income countries relative to baseline (i.e., no meat reduction)
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For purposes of comparison, Rosegrant mentioned results from a different modeling study, in which non-CO2 GHG emissions were examined under three different meat demand scenarios (constant, more, and less)
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So again, Rosegrant observed, reduced meat consumption was projected to have very large impacts on GHG emissions. Final Remarks In conclusion, Rosegrant summarized three main points.
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Fish grown in ponds or nets suspended in the ocean are associated with higher GHG emissions, he noted, similar to those of chicken, but if aquaculture uses pumps to recirculate and filter the water, emissions can be similar to those of trawling fisheries because of the energy required of the pumps ("recirculating aquaculture" in Figure 3-2)
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From page 49... ...
With respect to the risk factor estimates themselves, he continued, estimates for micronutrient deficiencies, for instance, have been very unstable because of the assumptions that must be made about daily versus usual intake. He mentioned that GBD has been working with FAO to reevaluate estimates of micronutrient deficiency.
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Instead of focusing on preferences, Rosegrant suggested, another strategy is to use punitive taxes, either carbon taxes, which would be far higher for meat than for other, healthier foods, or direct meat taxes. He acknowledged, however, that such taxes would be a "tough sell" in a country such as the United States, and that in most of Africa and much of Asia, where people are eating only 1 to 2 kilograms of meat per capita daily, even substantial increases in meat consumption could be beneficial.
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However, when meat consumption in high-income countries plus Brazil and China was reduced by 50 percent, there would still be a 10 percent increase globally by 2050 because when that much demand is removed from the global meat system, prices fall, making meat more affordable for more people (Tilman and Clark, 2014)
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