European dietary patterns and their associated land use: variation between and within countries Henri de Ruitera,b, Thomas Kastnerb, Sanderine Nonhebela a Center for Energy and Environmental Sciences, University of Groningen, P.O. Box 221, 9700 AE, Groningen, The Netherlands; b Institute of Social Ecology Vienna, Alpen-Adria Universität Klagenfurt, Wien, Graz, Schottenfeldgasse 29, 1070 Vienna, Austria henri.deruiter@hutton.ac.uk thomas.kastner@aau.at s.nonhebel@rug.nl Corresponding author Henri de Ruiter Information and Computing Sciences Group, James Hutton Institute, Craigiebuckler, Aberdeen AB15 8QH, Scotland UK henri.deruiter@hutton.ac.uk +44 (0) 844 928 5428 Acknowledgements TK acknowledges funding from the European Research Council Grant ERC-263522 (LUISE). 1. Introduction In the last decade, research on the environmental impact of food consumption patterns has increased. This is caused by the rising awareness that the consumption of food has major environmental consequences. For instance, it is estimated that 20-30% of the environmental impacts of final household consumption is due to our food (Tukker et al. 2011). Land use has been one of the main indicators of environmental impact, as there is an increasing debate about whether there will be enough suitable land for the production of food. It is estimated that 38% of total arable land is already in use for the production of food and it is expected that this will increase in the upcoming decades (FAO, 2011). Therefore, the relation between food consumption patterns and land use has become increasingly important as a topic for research. Land use is calculated for past and current situations for different regions (e.g. Geeraert, 2012; Zhen et al. 2010) and for future projections (e.g. Wirsenius et al. 2010). There are large differences in the use of land among individual food items (e.g. Gerbens-Leenes et al. 2002). For example, the production of meat in particular is inherently inefficient compared to plantbased food items, so the role of animal products in the use of land has been a prominent focus of research (e.g. Baroni et al. 2007; Nijdam et al. 2012). Identifying variations in the land use requirements of different food items leads to proposals for more sustainable diets. However, diets of people are more than the sum of individual food items. They are complex combinations of different food items, influenced by cultural and regional preferences. As a result, it might prove difficult to exclude individual land-intensive food items from a specific diet. Moreover, the land use impact of food items depends also on the productivity of a specific agricultural system. To investigate the influence of dietary patterns on land use, the combination of different dietary patterns and associated agricultural systems are analyzed here, to investigate sources of variation between European countries. This analysis can produce insights into the relation between dietary patterns and land use. The analysis is carried out by calculating the land use of the dietary patterns of 16 European countries. The food consumption data are obtained at the household level and thus represent a different scale than studies which use FAO data for their analyses. This finer spatial resolution of data for food consumption also allows the identification of sources of variation within countries. For the current analysis, education of the household head is investigated as a possible socioeconomic variable associated with variation in land use. Identifying variations in land use of dietary patterns between, and within, countries leads to a better understanding of the relation between dietary patterns, the agricultural system and land use. 1.1 Variation in land use between different dietary patterns There are differences in dietary patterns between and within European countries, resulting mostly from their different cultural norms (Naska et al. 2006). An early study on land use and dietary patterns, conducted by Gerbens-Leenes et al. (2002), developed a methodology for the assessment of land required for food and showed, in combination with household data, the land use for the Dutch consumption pattern in 1990. A follow-up study assessed the relative land use for 14 European countries, compared to the Dutch consumption pattern and land use in 1990 (Gerbens-Leenes & Nonhebel, 2005). This study showed large differences in land use for the existing dietary patterns in Europe. The total land use related to food consumption is determined by both consumption (type and amount of food products consumed) and production (high yields lead to a lower use of land) of food. The studies conducted by Gerbens-Leenes et al. (2002) and Gerbens-Leenes & Nonhebel (2005) used one production system (the Dutch system) for the calculation of the use of land; they were designed to show the relevance of specific dietary patterns for the use of land. A recent advancement in the methodology made it possible to also include other national production systems. Kastner et al. (2012) use an updated methodology and FAO data from 1961-2007 for a consistent comparison of land use in different subcontinents at different points in time. They show that variations in per-capita food supply are large and linked to income levels, especially qualitatively. On the other hand, variations in land use were less pronounced, and not clearly linked to income levels. This latter finding can be explained by large differences in output per unit land (production system). This emphasizes the importance of the production system in analyses about land use. We use the methodology from Kastner et al. (2012) to investigate whether differences in agricultural systems are a possible source of variation for the land use of European dietary patterns. A challenging issue in comparative studies on land use for food is the difference in collection methodology for food consumption data, since different definitions and methods exist for the recording of food consumption. To compensate for this, most comparative studies use food supply data obtained from the FAO food balance sheets (FBS). Because these data are harmonized as much as possible, using FAO data for inter-country comparisons is a common practice. Nevertheless, these data represent the national supply level, and information about consumption within the household is lost. On the other hand, analyses from single-country studies which use household data cannot be used for comparisons with other countries, as the methodology for the collection of household food data differs substantially between countries. Hence they cannot be used for the purpose of the current paper. In this paper, we use a standardized and post-harmonized databank, developed in the Data Food Networking Project (DAFNE). This dataset allows the assessment of land use associated with dietary patterns on the household level, without risking flaws because of differences in the collection methods. Minimizing the effects of differences in collection methods is essential for the purpose of our analysis, to exclude methodological differences as a source of variation. The DAFNE project exploits food and socio-demographic data collected in the household budget surveys (HBS), aiming at the development of a cost-effective food databank that allows monitoring of food availability both within and between European populations (Trichopoulou et al. 2003). Currently, 24 European countries are included in the database (DAFNE, 2005). The initiative is intended to be used as a cost-effective nutrition monitoring tool in a European context. The databank allows for comparison between countries and within countries. This latter fact makes it also possible to investigate the influences of socio-economic variables on land use. Since it is known that dietary patterns are also influenced by socio-economic factors, this represents a major advantage compared to the use of FAO national supply data. For instance, Hulshof et al. (2003) show that people with a high socio-economic status (SES) in The Netherlands consume more vegetables, cheese and alcohol, whereas people with a low SES consume more potatoes, meat and meat products, visible fats and coffee. Education is studied as a possible source of variation in this paper, since epidemiological studies show that it represents the strongest and most important social predictor in Western countries for a healthy diet (Johansson et al. 1999; Roos et al. 1996). People with a higher level of education generally have a healthier diet, characterized by a higher consumption of fruit and vegetables. For that reason, education is chosen as most likely source of variation for dietary patterns within European countries. Thus, this analysis uses the method by Kastner et al. (2012) and data obtained from the DAFNE databank to assess the land use related to the dietary patterns in Europe. We are able to incorporate both the influence of differences in consumption patterns as well as differences in the agricultural systems on total land use. The paper assesses both the cropland use of the European dietary patterns, as well as the effect of education on this land use. In doing so, this paper contributes to the body of knowledge on the relation between dietary patterns and land use. This is accomplished by using food consumption data on the household level instead of using data on a national supply level. 2. Methodology 2.1 Collection of household budget survey data The used food consumption data are freely available at the Dafnesoft website (DAFNE, 2005). The methodology for the collection of these data consists of several steps and is described in detail by Trichopoulou et al. (2003). A brief overview is given in this section. First, the data are collected from several European countries through household budget surveys (HBS). These surveys collect data on food availability at the household level. Hereafter, the raw HBS data are incorporated in a central database. The next step involves the post-harmonization of the food, demographic and socio-economic information. The final step comprises the calculation of the average, daily individual food availability. The average daily individual food availability is expressed in grams per day. The data obtained from this databank can be used for comparisons between and within countries. For comparisons within countries, food availability in the DAFNE databank can be obtained for different socioeconomic variables: education, occupation, locality and household composition. Education is chosen as socioeconomic indicator in the current study. The variable differentiates three categories in the data bank: ‘primary education / illiterate’, ‘secondary education’ and ‘higher education (college / university)’. Though differences in the national educational systems do exist, data on the education of the head of the household could be classified under these three comparable categories (Trichopoulou, 2008). The three categories are described in this paper as ‘elementary education’, ‘secondary education’ and ‘higher education’. The food availability data is grouped according to the highest education of the head of the household. Food availability data for 24 European countries are available, but the data for the United Kingdom do not include the indicator education, and the UK is therefore excluded. For some countries, surveys from several years are available; the surveys closest to the year 2000 are chosen. The included surveys range from 1988 to 2000. Table A.1 lists the included surveys and the sample information. Germany only has data available for the two highest educational levels: secondary and higher education. Luxembourg is excluded because of its small size and because yield data are only available in an aggregate with Belgium. 2.2 Methodological issues about household food consumption In the HBS and in this paper, household food consumption is conceived as household food availability, as opposed to household food intake. Food availability is a useful measure for our analysis, as the availability of food represents a larger amount of food than actual intake (including intake and household level waste). Consequently, availability of food has a higher environmental impact than food intake. Moreover, to our knowledge, there is no standardized and harmonized databank for food intake. Household food availability can be considered as ‘all food that enters the household’. For instance, food can also be consumed outside the household. The DAFNE initiative also focuses on the consumption outside the house. However, the majority of the European countries included in the DAFNE data list only expenses concerning out-of-home consumption (Trichopoulou et al. 2005). This is less accurate compared to quantity data. Another issue is whether meals of guests are included in the household consumption and whether food produced at home is included in the household food availability. Table A.1 lists the information about the inclusion of guest meals and the capturing of the seasonal variability. Table A.1 also presents the HBS included in this study and their main sample information. More information about the samples is available on the website (DAFNE, 2005). Waste throughout the food chain is not considered in the DAFNE dataset, as the collection method is aimed at the consumption of food within the household. 2.3 Collection of land use data Country-specific data for the land use for food are obtained from Kastner et al. (2012). The exact calculation of these land uses is explained in Kastner et al. (2012) and briefly described here. The land use for specific food items depends on the consumption of these items (information obtained from FBS) and on the yields of the corresponding crops (obtained from the FAO). Kastner et al. (2012) use country-specific yields to assess cropland use in a given nation. However, international trade poses a limit to this approach: food consumed in one country can originate from land within the country or from imports from outside. To account for this, Kastner et al. (2012) split the amount of a crop available within a country into shares of domestic production and imports. The land use for the domestic production is calculated using the domestic yields. For the import share, the authors performed a calculation to assess the average world market yield. The total land use is computed by adding up the domestic production and import land requirements. The calculated land use involves the demand for cropland, grassland and pastures are not included. Kastner et al. (2012) use the assumption that a calorie from animal origin needs three times more land than a ‘vegetal’ calorie (non-animal calorie). This assumption is based on a calculation comparing total feed input from cropland into the livestock sector to total livestock output. We were able to combine land use data and food consumption data for 16 of the 23 countries present on the DAFNE website. 2.4 Converting HBS data to land use data Figure 1 shows the steps used in this study. DAFNE data are obtained at the highest aggregation level, comprising 22 food categories (g/day/cap). Two food categories are investigated at a lower level: non-alcoholic beverages and total added lipids. The first category is examined at a lower level to exclude the availability data of mineral water, as no cropland is required for mineral water. The latter category is obtained at a lower level to discriminate between lipids from vegetal and animal origin. The land use data obtained from Kastner et al. (2012) are for the agricultural commodities used in the FAO food balance sheets. The food consumption data, however, are for food categories and not expressed in agricultural commodities. This requires an extra step to convert food consumption data to agricultural commodities, using equivalent factors. These equivalent factors are listed in table A.2. To give an example, one DAFNE category is ‘bread and rolls’ and it is assumed that 0.67 of this category consists of cereals. As table A.2 shows, a DAFNE category is only allocated according to the main FAO category. That is, the other 0.33 of the ‘bread and rolls’ category is not allocated to another FAO category. This is done because it is assumed that the other part consists mainly of water (this is the case for ‘Bakery products’; Bread and rolls’; and ‘Soft drinks’). Cheese is converted to milk equivalents, using the FAO extraction rate of 0.12 (FAO, 2001a). The next step in the calculation involves the conversion of quantities (in kg) to calories. This is necessary because the land use data are expressed in m2/kcal. FAO conversion factors are used for this step (FAO, 2001b). The conversion factors are on a lower aggregation level than the FAO categories. That is, conversion factors are available for food items (e.g. apples), but not for food categories (e.g. fruits). Therefore, assumptions are made to obtain a category conversion factor (see table A.3). The final step is the calculation of calories to land use. The land use data are obtained for each country from Kastner et al. (2012). These values are used to calculate the land use per kcal for each food category. By dividing the land use calculated by Kastner et al. with the caloric supply (obtained from the FBS), land use (m2/kcal) for each food category is obtained. For instance, the land use calculated for cereals in Austria (1999) equals 242 m2 per year and per capita. The amount of calories supplied by 242 m2 equals 905 kcal/day/capita. This implies that 0.27 m2/capita was needed in 1999 to provide a daily kilocalorie year-round. This value is multiplied with the caloric availability (DAFNE) used in this study. The land use (m2/kcal) differs per country and per year, as yields differ per country and per year. Appendix B lists the land use (m2/kcal) for each category in each year. 3. Results 3.1. Variation in land use between different European dietary patterns Figure 2 presents the land use for the 16 European dietary patterns, broken down by educational level. Large differences are seen between the countries. Malta has the largest land use (3,227 m2 for the elementary education group), while Ireland has the lowest land use (1,476 m2 for the elementary education group); the difference between the highest and lowest land use is thus a factor 2.2. In general, countries in Southern Europe have a much higher land use than countries in other parts of Europe. A major reason, not related to dietary patterns, is the production system of the European countries. To give an illustration, the agricultural system in Germany needed 0.22 m2 in 1998 to produce one daily kilocalorie of cereals year-round. In contrast, the agricultural system of Spain needed 0.54 m2 to produce this daily kilocalorie in 1998. This difference is caused by the higher yields in Germany. Therefore, although the caloric availability in Germany is higher than in Spain, the total land use of the German diet is lower than for Spain. This emphasizes that the influence of the local agricultural system is very significant. Another major reason for the differences in land use between European countries is the total caloric food availability. Generally, countries in Southern Europe have a large caloric availability (though the Iberian Peninsula seems to be an exception). Malta and Greece have, because of their high caloric availability and because of their production system, the highest land use. To exclude the effect of the total caloric availability on the calculated land use, the land uses of the 16 European dietary patterns are calculated to a 2,500 kcal diet (figure 3). Two scenarios are presented in figure 3, with the Austrian situation as reference (=100%). The first scenario is the calculation of the land use for a 2,500 kcal diet with country-specific yields. This scenario still includes the effects of the country-specific agricultural productivities and different composition of the diets. Countries with a percentage higher than 100% have a lower agricultural productivity compared to Austria. For instance, Spain and Portugal have an agricultural system with comparatively low land productivity. To further isolate the effect of the composition of the diet, the relative land use is calculated with one agricultural system and associated import ratio (Austrian system). This second scenario is also presented in figure 3 and shows the relative land use compared to the Austrian land use. Finland and France have the highest land use because of their dietary composition. This is caused by the high proportion of animal products in their diet (46% of total caloric availability). On the other hand, Hungary has the lowest relative land use. This is caused by the high proportion of cereals and low proportion of animal products in the diet. Overall, figure 3 shows that the relative land use is more affected by the differences in agricultural productivities than by differences in the composition of the diets. It can therefore be concluded that within Europe, the influence of the agricultural system is more pronounced than the effect of different compositions of the diets. 3.2 Contribution of different food categories to total land use Animal products contribute very substantially to the land use in every European country. On average, the share of animal products in total land use is more than 60%. France has the highest share of animal products in the total land use (more than 70%), while Italy has the lowest share (below 60%). Vegetable oils have a considerable share in the Southern countries. Vegetable oils represent the category with the most visible differences between the regions. Whereas the share of vegetable oils in the total land use is larger than 12% in Southern Europe, this share is around 7% in the other countries. Less visible differences are present for sugar & sweeteners (Southern countries consume less sugar, but as the land use for sugar is small, this does not contribute much to land use differences) and cereals. Eastern countries especially, such as Hungary and Poland, have a larger share of cereals in the total use of land. However, we have to take into account a possible time effect, as the year of the survey is ± 10 years earlier than most other surveys (1991 and 1988, respectively). It could be that the high cereals and low animal products share in these countries is a reflection of a European consumption pattern from a decade before the year 2000. Figure 2 also shows the caloric availability of the different food categories. It shows that cereals in general have a large share in the caloric availability, but that this share is much smaller in the land use picture. This is caused by the high efficiency of cereals production. The opposite is true for animal products. Animal products have a larger share in the total land use than in the caloric availability. This emphasizes the inefficiency of animal products. 3.3 Variation within countries: the influence of educational level Figure 2 clearly shows that people with an elementary education have higher caloric food availability and consequently a larger land use. This is true for all countries, except for Portugal. The difference between people with a secondary education and people with a higher education is less marked. As the production system is the same within countries, the differences can be attributed to dietary factors. Two dietary factors influence total land use: total caloric availability and composition of the diet. The caloric availability is substantially higher for the elementary education group. On average, people with an elementary education consume 2,809 kcal per day, while the other groups consume 2,380 kcal and 2,302 kcal, respectively. However, when the caloric shares are examined, few differences are observed. People with an elementary education seem to consume more vegetable oil and less animal products. This is caused by the lower milk (and milk products) consumption of the elementary education group. The caloric shares indicate that people with a higher education consume more fruits and less starchy roots. There is no observable difference for the cereals category. To separate the effect of caloric availability and composition of the diet, we calculated the relative land use for the different education groups, based on a 2,500 kcal diet. Across all the countries, the relative cropland use (for a 2,500 kcal diet) is on average 2,096 m2 for the elementary education group; 2,116 m2 for the secondary education group; and 2,141 m2 for the higher education group. The variation for individual countries is large, as both caloric availability and yields differ, but it could hint at a trend, namely, that people with a higher education consume more ‘costly’ calories (in terms of land use per kcal). This is demonstrated by the fact that 14 out of 16 countries (Germany is excluded because it has no ‘elementary education’ category) have a higher relative land use for the higher education group compared to the elementary education group. Although the differences are not very large (the highest difference is 9%), it is a consistent finding in the current analysis. This could be explained by the higher share of animal products (i.e. milk) in the total land use for the higher education group. 4. Discussion In the past decades, the analysis of dietary patterns, in addition to studying individual dietary components has emerged as a method of exploring the relations between diet and disease (Hu, 2004). This shifting focus is caused by the increasing recognition that the intake of various dietary factors is highly correlated, and many interactions between components of a diet and disease risk may exist. The same development has taken place for the relation between dietary patterns and land use in the past decade: shifting away from individual food items to the analysis of complete dietary patterns. The analysis presented in this paper is based on one point in time and represents a ‘snap-shot’ of the situation around the year 2000. Using this snap-shot, sources of variation can be observed and investigated. The objective of this paper is therefore not to obtain a perfect, quantitative picture of the cropland required for food; rather, the focus is on sources of variation and relative differences between the land use related to the European dietary patterns. 4.1 Variation in land use between European dietary patterns The variation in land use related to European dietary patterns is large, with a factor 2.2 difference between the lowest land use and the highest land use between countries. The current analysis shows that two factors are responsible for the main differences in the land use of the European dietary patterns: caloric availability and the productivity of the agricultural system. The influence of differences in the composition of the diet between countries is minor, suggesting that the dietary patterns in Europe are quite similar and that, on this level of aggregation, the differences between countries do not lead to large variation in land use. It is not suggested that the composition of the diet has no effect at all on the land use for food. A radical switch to a vegetarian diet would drastically decrease the land use. Moreover, Kastner et al. (2012), show that dietary change is an important contributor to the impact of diets worldwide, especially in (Eastern) Asia. The current analysis does not discriminate between the land use of, for instance, different livestock products. Bovine meat needs in general more land than poultry or pork meat, however much of this difference is explained by the need for grazing lands which were not part of our analysis. As the total land use is greatly influenced by consumption of animal products, the differences in land use of specific animal products may increase the differences between the land use of different dietary patterns. On the other hand, increasing the level of detail would add another level of complexity, which would lead to more unwanted variation caused by methodological differences. For the resolution of dietary patterns considered in our analysis, the composition of the diet is not a major source of variation between national European dietary patterns. Gerbens-Leenes & Nonhebel (2005) also calculate the relative differences for the land use related to food of different European countries. In their analysis, the difference between the highest relative land use and the lowest relative land use is 37%. In the current analysis, the difference in relative land use for a 2,500 kcal diet is 25% (figure 3). Without this caloric standardization, the difference increases to 56%. This suggests that, although the study by Gerbens-Leenes & Nonhebel (2005) is on a national food supply level, the relative differences in land use are of the same order of magnitude, although it might also suggest that differences between countries are higher when using household data for the calculation of land use related to food consumption. When the individual countries are examined, France has the highest land use in both analyses, but the order in the countries differs substantially between the two analyses. One of the reasons is that Gerbens-Leenes & Nonhebel (2005) do not correct for the caloric availability. If figure 3 is constructed without correction for caloric availability, the order of the countries is more similar to Gerbens-Leenes & Nonhebel (2005). If we compare the land use of the current analysis to the land use calculated with FAO data by Kastner et al. (2012), the FAO land use calculations are higher than the calculations in this paper. FAO calculations for the year 2000 show an average land use of 2,632 m2 for Eastern Europe (1,750 m2 for secondary education group in this paper); 1,909 m2 for Northern Europe (1,834 m2); 3,108 m2 for Southern Europe (2,546 m2); and 2,024 m2 for Western Europe (1615 m2). Although the regions in the Kastner et al. (2012) study involve more countries, this comparison suggests that land use calculated with FAO data leads to higher estimates of land use due to the dietary patterns in Europe. This is in line with other studies which show that FAO data are consistently higher for food consumption than HBS data (Elmadfa, 2009; Naska et al. 2009; Pomerleau et al. 2003; Serra-Majem et al. 2003). Therefore, the analysis of land use for food on the household levels is a valuable addition to existing studies on a national food supply level. After all, household food consumption data is a more specific reflection of the actual per capita food consumption than FAO data. Food supply on the national level can display large national trends in the supply of food per capita, whereas household food availability is better able to show the actual dietary patterns in a country. The assessment of land use related to food consumption on a household level is, therefore, more specific than on the national supply level, and represents a further advancement in the assessment of the effect of the dietary patterns on land use. The single largest contributor to the total land use is the consumption of animal products. In each country, the share of animal products in the total land use is higher than 50%. As the total share of animal products in the caloric availability is in the order of 30-45%, this emphasizes the high land use of animal products. Vegetable oils are consumed in larger quantities in the Southern countries, while the consumption of sugar & sweeteners is lower in these countries. The differences in the caloric shares of the food categories are relatively small and have a minor effect on the total land use. Despite this small effect, the differences in land use related to the dietary patterns are prominent. This is caused by the different agricultural systems. A highly productive agricultural system, combined with suitable local circumstances, leads to high yields and thus to low land use for food. Especially the countries in Southern Europe have lower productive agricultural systems. The more arid climate of these countries is one of the obvious reasons for the low productivities of these countries. Naska et al. (2006) suggest that the dietary patterns of Europe are narrowing towards a more uniform pattern. However, in an environmental context, it is likely that the differences in land use will continue to exist, as local climate circumstances will be playing a major role in the productivities of the agricultural systems. 4.2 Variation in land use within countries: influence of educational level This paper shows that people with an elementary education have a larger land use than people with a secondary or higher education. The main reason for this result is that people with a lower education have a higher caloric availability. The differences in the composition of the diets have a very small effect and suggest that people with a higher education consume more ‘costly’ calories. This effect slightly counteracts the larger land use of the lower education group. As a result, it can be concluded that the largest part of the variation in land use within countries is caused by the caloric availability. People with a lower education could consume more food, but they could also waste more food. Results from the literature for the relation between education (or SES) and caloric intake are mixed. Hulshof et al. (2003) show a significant effect for men between a ‘high’ and ‘low’ socioeconomic status (high SES is associated with lower caloric availability) in The Netherlands; no effect was found for women. A review by Darmon & Drewnowski (2008) shows inconsistent results for this correlation. A systematic review conducted by Giskes et al. (2009) for European countries, shows the same result, no consistent association between socio-economic status and energy intakes, despite the fact that the prevalence of obesity is higher among socioeconomic disadvantaged groups. This is not the case for the current results; almost all countries show a higher caloric availability for the elementary education group. One of the reasons could be that in the current study, education was the sociological factor, while other definitions of SES sometimes include occupation, income or other factors. Education is chosen in this paper as the major socio-economic variable, since research indicates that education is the most consistent predictor of a healthy diet. Common indicators for a healthy diet consist of specific measures, such as the amount of fruits and vegetables, fibre, fat as percentage of total energy intake, (e.g. Johansson et al. 1999). It may be that education is a good predictor for a healthy diet, but not as an indicator for an environmental-friendly diet. For instance, fruits and vegetables barely show up in the current land use pictures, as their caloric content is very low. Therefore, choosing other socio-economic variables as sources of variation may lead to other results. We used the same level of aggregation for food consumption within countries. Thus, we did not discriminate between different animal products. Although we did not study this in detail, it seems that especially higher educated people consume relatively less pork (DAFNE, 2005). An interesting observation is that Southern countries have a diet characterized by the high amounts of vegetable oils, especially olive oil. Olive oil is generally considered as part of a healthy diet. In the current analysis, the high availability of vegetable oils contributes to the higher land use for the Southern countries. The other European countries have considerably higher caloric shares of sugar & sweeteners, which are not necessarily part of a healthy diet. However, the high share of sugar does not translate in a large use of land, as sugar is very efficiently produced. Therefore, there might be trade-offs between some food categories in obtaining both a healthy and environmental-friendly diet. 4.3 Conclusions and implications The calculated cropland use related to European dietary patterns ranges from ± 1,500 m2 per capita to ± 3,000 m2 per capita. This paper shows that agricultural systems and total caloric availabilities are the largest sources of variation in the land use of European dietary patterns. The composition of the diet between countries is a much smaller source of variation, at least at this level of aggregation. Using educational level as a proxy for differences within countries, it is shown that caloric availability is the major source of variation in land use within countries and that people with low education need more land to sustain their dietary patterns. Using household food consumption data leads to lower land use estimates associated with dietary patterns than FAO data. As household food consumption data are a better reflection of dietary patterns, the use of these data is a valuable addition to FAO data analyses. The current analysis emphasizes the relevance of an efficient agricultural system and the total availability of calories. Moreover, our results suggest that people with a higher education consume less calories, and hence have a lower demand for land. References Baroni, L., Cenci, L., Tettamanti, M., Berati, M., 2007. Evaluating the environmental impact of various dietary patterns combined with different food production systems. Eur J Clin Nutr, 61, 279-286 DAFNE, D. F. N. 2005. The pan-european food data bank based on household budget surveys. Retrieved 08/03, 2012, from http://www.nut.uoa.gr/Dafnesoftweb/ DAFNE IV., 2003. European Food Availability Databank based on Household Budget Surveys – Annex 3: Comparable categories of socio-demographic data. Retrieved 08/23, 2012, from http://ec.europa.eu/health/ph_projects/2002/monitoring/monitoring_2002_04_en.htm Darmon, N., & Drewnowski, A., 2008. Does social class predict diet quality? Am J Clin Nutri., 87(5), 1107-1117. Drewnowski, A., & Specter, S. E., 2004. Poverty and obesity: The role of energy density and energy costs.. Am J Clin Nutri., 79(1), 6-16. Elmadfa et al. (2009). European nutrition and health report 2009. Basel: European Commission, Health and Consumer Protection. FAO., 2001a. III. Procedures for Preparation of Food Balance Sheets – 3. Livestock Sector. In: Food balance sheets - A handbook –Rome: Food and Agricultural Organization of the United Nations. FAO., 2001b. Food balance sheets - A handbook - annex I. Rome: Food and Agricultural Organization of the United Nations. FAO., 2011. The state of the world's land and water resources for food and agriculture (SOLAW) managing systems at risk. Rome; London: Food and Agricultural Organization of the United Nations; Earthscan. Geeraert, F., 2012. Sustainability and dietary change: the implications of Swedish food consumption patterns 1960-2006. Int J Consum Stud Gerbens-Leenes, P. W., Nonhebel, S., & Ivens, W. P. M. F., 2002. A method to determine land requirements relating to food consumption patterns. Agri.,, Ecosyst. and Environ., 90(1), 47-58. Gerbens-Leenes & Nonhebel, S., 2005. Food and land use. The influence of consumption patterns on the use of agricultural resources. Appetite, 45: 24-31 Giskes, K., Avendano, M., Brug, J., Kunst, E.A., 2009. A systematic review of studies on socioeconomic inequalities in dietary intakes associated with weight gain and overweight/obesity conducted among European adults. Obes Rev., 11: 413-429 Hu, F.B., 2002. Dietary pattern analysis: a new direction in nutritional epidemiology. Curr Opin Lipidol 13, 3–9 Hulshof, K. F. A. M., Brussaard, J. H., Kruizinga, A. G., Telman, J., & Löwik, H., 2003. Socioeconomic status, dietary intake and 10 y trends: The dutch national food consumption survey. Eur J Clin Nutr, 57, 128-137. Irala-Estévez, J. D., Groth, M., Johansson, L., Oltersdorf, U., Prättälä, R., & Martínez-González, M. A., 2000. A systematic review of socio-economic differences in food habits in europe: Consumption of fruit and vegetables. Eur J Clin Nutr, 54(9), 706-714. Johansson, L., Thelle, D.S., Solvoll, K., Bjorneboe, G.A., Drevon, C.A., 1999. Healthy dietary habits in relation to social determinants and lifestyle factors. Br J Nutr, 81, 211-220. Kastner, T., Rivas, M. J. I., Koch, W., & Nonhebel, S., 2012. Global changes in diets and the consequences for land requirements for food. PNAS, 109(18), 6868-6872. Naska, A., Fouskasis, D., Oikonomou, E., Almeida, M.D.V., Berg, M.A., Gedrich, K., Moreiras, O., Nelson, M., Trygg, K., Turrini, A., Remaut, A.M., Volatier, J.L., Trichopoulou, A., DAFNE participants., 2006. Dietary patterns and their socio-demographic determinants in 10 European countries: data from the DAFNE databank. Eur J Clin Nutr, 60: 181-190. Naska, A., Berg, M. A., Cuadrado, C., Freisling, H., Gedrich, K., Gregorič, M., et al., 2009. Food balance sheet and household budget survey dietary data and mortality patterns in Europe. Br J Nutr, 102, 166-171. Nijdam, D., Rood, T., Westhoek, H., 2012. The price of protein: Review of land use and carbon footprints from life cycle assessments of animal food products and their substitutes. Food Policy, 37(6): 760-770. Pomerleau J., Lock, K., McKee, M., 2003. Discrepancies between ecological and individual data on fruit and vegetable consumption in fifteen countries. Br J Nutr, 89(6): 827-834. Roos, E., Prättaäla, R., Lahelma, E., Kleemola, P. & Pietinen P., 1996. Modern and healthy?: socioeconomic differences in the quality of diet. Eur J Clin Nutr 50, 753–760. Serra-Majem, L., MacLean, D., Ribas, L., Brulé, D., Sekula, W., Prattala, R., et al., 2003. Comparative analysis of nutrition data from national, household, and individual levels: Results from a WHOCINDI collaborative project in canada, finland, poland, and spain. Journal of Epidemiology and Community Health, 57(1), 74-80. Trichopoulou, A., & Naska, A., 2003. European food availability databank based on household budget surveys. Eur J Pub Health, 13(3 Supplement), 24-28. Trichopoulou, A., Naska, A., & Oikonomou, E., 2005. The DAFNE databank: The past and future of monitoring the dietary habits of europeans. J Publ Health, 13(2), 69-72. Trichopoulou A., 2008. Final Implementation Report of the DAFNE V Project. Agreement No SPC.2003117. Tukker, A., Goldbohm, R.A., de Koning, A., Verheijden, M., Kleijn, R., Wolf, O., Pérez-Domínquez, I., Rueda-Cantuche, J.M., 2011. Environmental impacts of changes to healthier diets in Europe. Ecol Ec, 70: 1776-1788. Zhen, L., Cao, S., Cheng, S., Xie, G., Wei, Y., Liu, X., Li, F., 2010. Arable land requirements based on food consumption patterns in rural Guyuan District, Western China. Ecol Ec, 69(7): 14431453. Appendix A - Equivalence factors and Caloric conversion factors Country Year Sample size Austria Belgium Cyprus Finland France Germany Greece Hungary Ireland Italy Malta Norway Poland Portugal Spain Sweden 1999 1999 1996-1997 1998 1991 1998 1998 1991 1999 1996 2000 1996-1998 1988 2000 1998-1999 1996 7,098 3,745 3,308 4,359 12,680 6,258 11,813 7,644 22,740 2,586 22,740 29,664 10,024 14,644 2,026 1 Meals guest included Yes Yes Yes Yes Yes No Yes Yes No No No Yes Yes Yes Yes Recording period 14 days 1 month; 3 month for bulk1 14 days 14 days 7 days One quarter 14 days 2 months 14 days 10 days 21 days 10 days 3 months 14 days 7 days 14 days 1-month intensive recording + 3 months retrospective recording for bulk expenses Table A.1. Survey characteristics (DAFNE, 2005). DAFNE Levels FAO Category Equivalence factor Bakery products Cereals 0.67 Beverages, Alcoholic Alcoholic Beverages 1 Bread and Rolls Cereals 0.67 Cereals and Products Cereals 1 Cheese Milk 8.33 Eggs Animal products 1 Fish and Seafood Animal products 1 Flour Cereals 1 Fruits Fruits 1 Juices Fruits 1 Meat and products Animal products 1 Milk Milk 1 Milk products Milk 1 Nuts Oil crops 1 Pasta Cereals 1 Potatoes Starchy Roots 1 Pulses Pulses 1 Soft drinks Sugar & Sweeteners 0.1 Stimulants Stimulants 1 Total added lipids animal Animal products 1 Total added lipids vegetal Vegetable Oils 1 Vegetables Vegetables 1 Table A.2. DAFNE levels (DAFNE, 2005), corresponding FAO categories and equivalence factors (FAO, 2001a). FAO Category Cereals Animal products Milk Vegetable oils Fruits Oilcrops Vegetables Pulses Starchy roots Sugar & sweeteners Stimulants Alcoholic beverages Caloric value (kcal/kg) 3340 2480 610 8840 510 5800 270 3410 670 3870 480 585 FAO conversion factor used Wheat ⅓ Beef preparations + ⅓ Pig meat + ⅓ Poultry meat Cow milk, whole fresh Olive Oil ⅓ Bananas + ⅓ Apples + ⅓ Fruit, nes, fresh Groundnuts prepared ⅓ Onion + ⅓ Tomato + ⅓ Carrot Beans, dry Potatoes Sugar Refined ½ Tea + ½ Coffee roasted ½ Beer Barley + ½ Wine Table A.3. Caloric conversion factors used throughout the study. Based on FAO (2001b). Appendix B - Relative cropland use The data are based on the cropland use calculated by Kastner et al. (2012) and FAO consumption data (in kilocalories). The calculation is performed by dividing the total land use with the total caloric supply according to the FAO. This is done for each of the FAO food categories. The results differ per country and are shown in the tables. The year used for the calculation is the same year as the survey data (see table 2 in the main article). Category Austria Belgium Cyprus Finland France Germany Greece Hungary Alc. Bev. Cereals Fruits Oil crops Pulses St. Roots Stimulants Sugar & Sweeteners Veg. Oils Vegetables Animal Products 0.36 0.27 0.46 0.65 0.57 0.17 8.77 0.20 0.38 0.40 0.56 0.72 0.63 0.14 10.27 0.21 0.40 0.38 0.45 0.71 0.55 0.13 8.66 0.24 0.41 0.50 0.59 0.66 1.08 0.25 10.20 0.20 0.73 0.22 0.45 0.76 0.62 0.18 7.34 0.22 0.28 0.22 0.55 0.52 0.37 0.14 3.39 0.20 0.39 0.56 0.81 1.55 0.69 0.25 4.79 0.20 0.39 0.29 0.72 0.50 0.53 0.37 8.33 0.22 0.44 0.58 1.19 0.51 0.47 1.23 0.49 0.44 1.28 0.57 0.78 1.61 0.46 0.89 1.32 0.43 0.72 1.09 0.70 0.65 1.78 0.54 1.07 1.35 Category Ireland Italy Malta Norway Poland Portugal Spain Sweden Alc. Bev. Cereals Fruits Oil crops Pulses St. Roots Stimulants Sugar & Sweeteners Veg. Oils Vegetables Animal Products 0.20 0.32 0.69 0.64 0.35 0.19 3.21 0.21 0.56 0.45 0.95 1.19 0.53 0.23 10.59 0.22 0.29 0.48 0.68 0.95 0.41 0.27 1.40 0.20 0.38 0.37 0.60 0.99 0.58 0.20 5.11 0.20 0.27 0.52 0.84 0.76 0.52 0.29 8.31 0.21 0.62 0.52 1.10 1.52 0.90 0.35 2.72 0.22 0.75 0.54 0.63 1.28 1.64 0.21 7.60 0.20 0.32 0.26 0.73 0.69 0.44 0.17 10.83 0.21 0.48 0.59 1.04 0.73 0.67 1.71 0.61 0.88 1.45 0.51 0.80 1.37 0.40 0.74 1.31 1.06 0.75 1.97 1.04 0.65 2.16 0.43 0.66 1.24 Table B.1 Cropland use (m2/year) to provide 1 kcal/day. Relative cropland use for different food categories and countries. 1. Survey-specific quantity data aggregated into FAO categories 2. Quantities converted to calories using FAO conversion factors 3. Calories calculated to cropland use using country-specific data (Kastner et al. (2012)) Figure 1. Scheme showing the calculation procedure for this study Elementary Secondary 4000 3500 3000 2500 2000 1500 1000 500 0 Higher Elementary Secondary Higher Malta Elementary Secondary 4000 3500 3000 2500 2000 1500 1000 500 0 4000 3500 3000 2500 2000 1500 1000 500 0 4000 3500 3000 2500 2000 1500 1000 500 0 4000 3500 3000 2500 2000 1500 1000 500 0 4000 3500 3000 2500 2000 1500 1000 500 0 Higher Caloric availability (kcal/day) Calories Caloric availability (kcal/day) Calories Land 4000 3500 3000 2500 2000 1500 1000 500 0 Caloric availability (kcal/day) Calories Land Calories Land Calories Land Calories 4000 3500 3000 2500 2000 1500 1000 500 0 Calroic availability (kcal/day) Elementary Secondary Calories Elementary Secondary Land Elementary Secondary Land Hungary Calories Land Calories France Calories Land Calories Land Calories Land Calories Land Calories Land Calories Land Calories Land Calories Land Cropland use (m2/year) Belgium Calories Land Higher Calories Higher Land Calories Land Calories Higher Land Secondary Land Secondary Calories Italy Secondary Land Elementary Calories Greece Calories Elementary Land Calories Finland Land Calories Land Calories Elementary Land Higher Calories Higher Land Calories Land Calories Land Calories Land Cropland use (m2/year) Higher Land Elementary Secondary Calories Elementary Secondary Land Calories Land Calories Land Cropland use (m2/year) Elementary Secondary Land Calories Land Calories Land Cropland use (m2/year) Austria Cyprus Higher Germany Higher Ireland Higher Norway Higher Elementary Sweden Elementary Secondary Higher Caloric availability (kcal/day) Calories Land Calories Land 4000 3500 3000 2500 2000 1500 1000 500 0 Calories Higher Elementary Secondary Calories Land Calories Land Calories Land Calories Land Calories Land Secondary Higher Alc. Beverages + Stimulants 4000 3500 3000 2500 2000 1500 1000 500 0 Land Calories Land Calories Land Calories Calories Land 4000 3500 3000 2500 2000 1500 1000 500 0 Elementary Secondary Cropland use (m2/year) Spain Sugar & sweeteners Vegetable oils Pulses + Starchy Roots Fruits & Vegetables Animal products Cereals Oilcrops Figure 2. Cropland use associated with dietary patterns of European countries, for different education groups. Caloric availability (kcal/day) Portugal 4000 3500 3000 2500 2000 1500 1000 500 0 Land Cropland use (m2/year) Poland Relative cropland use (Austria = 100%) Cropland use for 2,500 kcal diet 250% 200% 150% 100% 50% 0% Country-specific productivities Austrian productivities Figure 3. Relative cropland use for a diet with 2,500 kcal, calculated for the secondary education groups. The Austrian situation is the reference situation. ‘Country-specific productivities’ is the calculation with country-specific yields. Thus, countries with percentages >100% have a lower land productivities compared to the Austrian system or a more landintensive diet. ‘Austrian productivities’ is the calculation with Austrian yields for all countries. The effect of different productivities is therefore excluded, and the differences can be explained by the variations in the composition of the diets. Countries with percentages >100% have a more land-intensive diet compared to Austria.