Environmental and nutritional impacts of changing diets and food waste in Spain

Abstract

Global food demand is increasing and changing rapidly because of multiple drivers including population growth, dietary shifts, and economic development. Improving the sustainability of global food systems is a top priority, although many of the efforts that have been made during the last decades have only targeted the production side and supply chain, like increasing agricultural productivity or expanding the agricultural area. Yet, managing food consumption demand, i.e., people’s eating habits might deliver not only health, but also important co-benefits from a land, water, and energy perspective. The promotion of responsible consumption, that is, sustainable-healthy diets and reduced food loss and waste, is a key strategy to achieve environmental benefits, sustainable food security, and to enhance public health.\nThe need to combine supply and demand management approaches to increase global food security in a sustainable manner is an embedded principle of the United Nations’ Sustainable Development Goals (SDGs). Among the different goals and targets, SDG 12 focuses on responsible consumption and production in order to achieve environmental benefits and sustainable food security. In addition to the environmental impacts, dietary shifts can cause important health problems such as coronary diseases, diabetes, and obesity. Countries like Spain are making significant efforts to reduce food loss and waste, reverse growing obesity trends, and promote the adoption of healthier food habits like the recommended and traditional Mediterranean Diet. This is recognized as a key strategy to improve the population´s health with locally grown, traditional, and seasonal products like fruits, vegetables, olive oil, and fish. Nevertheless, current Spanish consumption patterns (especially among younger generations, and urban and/or low-income citizens), appear to be shifting towards unhealthier diets.\nWith a view to connect water, agriculture, environment, food security, nutrition and health, this research aims to investigate the current dietary patterns of Spanish consumers and the possible shifting away that they are doing from a traditional and recommended Mediterranean diet, as well as households’ food waste generation, assessing their water and nutritional impacts. Therefore, this Thesis offers three complementary perspectives within SDG 12, by seeking to fill some knowledge gaps in the water and nutritional impacts of food consumption, and focusing on Spain’s households’ current food trends, agricultural trade, food waste, and two types of recommended diets. The first research within the Thesis assesses and compares the water footprint (WF) of two recommended diets; the Mediterranean and American, in order to asses’ Mediterranean diet as a sustainable dietary pattern, and to evaluate the water savings of possible dietary shifts in two countries: Spain and the United States (US). The results show that the American diet has a higher total WF in comparison with the Mediterranean one, regardless of where the products are produced. In the US, a shift to a Mediterranean diet would decrease the consumptive WF (Green + Blue WF) by 29% (1252 liters/capita day). Meanwhile, a shift towards an American diet in Spain will increase the consumptive WF also by 29 % (1277 liters/capita day). The largest share of the WF of both diets is always linked to green water, which implies that the largest impact of dietary shifts is also linked to land use. Grey water in the US is 67 % higher than in Spain. Moreover, only five products account for the larger share of the total WF of the two dietary options in both countries, being meat, fats, oil, and dairy products the food items with the largest WFs.\nThe second research study within the Thesis focuses on assessing the water-related implications of food consumption and waste among Spanish households’ consumers to discern possible policy recommendations. Paying attention also, to the water impacts in Spain and other countries, from which food is imported (i.e. Virtual Water and food trade). The results showed that, for the 12-month period starting on October 1st 2014, the Total WF of current consumption in Spain is equivalent to around 3,302 liters/capita day (of which 2,555 are Green, and 400 Blue WF). The products that account for the largest share in the total WF are once again meat, animal fats, and dairy products. Likewise, roughly, 41% of the total WF linked to household diets is foreign, i.e. imported Virtual Water, and the main countries of origin are Tunisia, Portugal, and France. The Total WF of food waste at households’ level is estimated at 131 liters/cap day (of which 97 are Green and 19 Blue WF), equivalent to 4% of the Total WF of current consumption. In addition, regarding nutritional analysis, the nutrients wasted (because of food waste) per capita year were 40,385 kcal, almost 7.5 kg of macronutrients (proteins, fats, and carbohydrates), 483 grams of fiber and almost 160 grams of micronutrients (vitamins and minerals). The third research study within the Thesis aims to assess and compare the nutritional and water implications of current food consumption of Spanish households with the recommended Mediterranean diet. Moreover, to calculate their nutritional composition, compared their water footprints, and developed a new methodological approach to assess the nutritional water productivity (i.e. the nutritional value per unit of water embedded). Results show that current Spanish household diet is shifting away from the recommended Mediterranean towards alternative diet containing three times more meat, dairy and sugar products, and 1/3 fewer fruits, vegetables and cereals. The Mediterranean diet is also less caloric, as it contains lesser amounts of proteins and fats, and richer in fiber and micronutrients. Due to the high water content embedded in animal products, a shift towards a Mediterranean diet would reduce about 753 liters/capita day the consumptive water (of which 34 are Blue WF). In addition, the Mediterranean diet has higher water-nutritional efficiency than Current consumption: more energy, fiber, and macro- and micro-nutrients are available per liter of consumptive water used. \nIn light of these results, a shift back to a locally produced Mediterranean diet (in which fruits, fish and vegetables account for a larger share of the food intake) and lessening food waste, would deliver greater water savings (753 and 116 liters of consumptive water/capita day, respectively) and nutritional benefits. Consequently, the preservation and further adoption of the Mediterranean diet, as well as minimize food waste in a household level, especially among young and urban generations, is an important goal to be achieved for Mediterranean countries, and potentially other ones.