Recherche Carnets de chercheur Kotaro FUKUHARA


Elucidating the driving forces of the dietary transition and its impact on environment: A case study of consumption patterns of edible fats and oils in France and Japan


Modern world has experienced a dramatic transformation of its dietary habits in accordance with economic growth and globalization. It is widely observed in the current developed countries that a shift from mostly grain-based, self-sufficient and subsistence diet to diversified and commercialized diet with abundance of animal products and processed food has occurred since the last century. In particular, meat and dairy products, sugar, and edible fats and oils have shown considerable increase in their consumption per capita, whereas consumption of traditional staple food, such as wheat products in Western countries and rice in Japan, shown gradual decrease trend. Despite the observation of the general trend of such dietary transition, its main driving force(s) (i.e. contributing factors) have still remained to be fully elucidated.Dietary transition is often pointed out to be enhancing environmental impact in the shape of an expansion of new farmland and degradation of existing farmland for satisfying increasing demand of agricultural products. For instance, the rapid increase in demand of oil crops and animal feed in China is said to be causing deforestation and soil degradation in Southeast Asia and Latin America, where China imports a large amount of palm oil and soybeans respectively.
Purpose of the Research:

This research attempts to find out the main driving force(s) which cause the dietary transition through a case study for a transition of consumption patterns of edible fats and oils in France and Japan in the 20th century. Subsequently, we evaluate the environmental impact by the dietary transition in those two countries focusing on land use change.

As shown in Figure 1 and Figure 2 below, consumption patterns of fats and oils have been entirely different and distinctive between France and Japan. Per capita consumption of fats and oils in Japan in 2011 is only a half of that in France. This gap is mainly due to the difference of animal fats consumption such as butter and cream. French people are consuming 13.5kg/capita of animal fats as of 2011, whereas Japanese people are consuming only 1.5kg/capita of them. Although consumption of vegetable oils in total are not that much different in the two countries (21.0kg in France and 15.6kg in Japan as of 2011), its consumption structure is totally different. Whilst France is consuming various types of oil such as sunflower oil, soybean oil, and rapeseed oil and olive oil, Japan is mostly depending on rapeseed oil and soybean oil.
Figure 1. Per capita supply of edible fats and oils in France (1961-2011)
Figure 2. Per capita supply of edible fats and oils in Japan (1961-2011)

One reason of the contrast is a difference of cultural importance of fats and oils, especially for culinary customs, of France and Japan. Although butter, cream and other animal fats have played a significant role in French cuisine, fats and oils have not so much emphasized in Japanese traditional cuisine except several kinds of fried foods such as tempura. Another reason of the contrast can be attributed to political issue. In France, for example, production and distribution of dairy products and oil crops such as rapeseed and sunflower have been strongly controlled and intervened by its governmental policy, in order to encourage self-sufficiency of the products. In Japan, on the other hand, there has been quite a small intervention on oil crops by the government since the 1960s.
Also, as observed from the Figure 1 and Figure 2 above, per capita consumption of fats and oils has shown an increasing trend until the 1990s both in France and Japan. Such a dietary transition would require further production of fats and oils and it might in turn boost an environmental impact through an expansion of new farmland and degradation of existing farmland by intensified use. As shown in Table 1 below, oil crops, which are origins of vegetable oils, occupy large part of world farmland at present. In addition, in order to produce animal fats (butter and cream as dairy products and lard and tallow as by-products of meat), large amount of feed crops such as maize and soybeans are also required to raise the livestock. In total, the environmental pressure on land use for producing fats and oils would be notable.
Table 1. World top 20 crops for land occupation and their principal use
Source: FAOSTAT  
Analysis and its Methodology:

1) Elucidating the main driving force(s) of dietary transition

As for the driving forces for the dietary transition of fats and oils, the following five factors are taken account. Also, mutual relations among the dietary transition, the driving forces, and their impacts on environment and human health are shown in Figure 3. In this chart, arrows show causal relations, green rounded squares show driving forces, red rounded squares show eventual impact by the dietary transition, and gray rounded squares show other exogenous factors.

  • Economic factor: product price compared with people’s income (purchasing power and availability)
  • Socio-cultural factor: cultural preference, tradition of culinary use, influence of mass media, etc.
  • Political factor: governmental policy related to agriculture, food supply, environment and public health
  • Educational and rational factor: public concern regarding health and nutrition
  • Instinctive factor: food appetite and physiological desire

Figure 3. Correlation diagram of dietary transition: the driving forces and eventual impacts

As a hypothesis, the economic factor causes dietary transition directly through increases of availability and purchasing power of people. The socio-cultural factor also directly induces dietary transition through handling people’s preference and acceptability from both cultural and social aspects. The educational and rational factor attempts to take control of dietary habits and to push it towards a model of so-called “ideal diet”, while the instinctive factor is often counteractive to that, stimulating and driving people to follow their own desires. On the other hand, the political factor is just indirectly involved with the transition by affecting other driving forces in the shape of policy implementation (e.g. performing education campaign to enhance public awareness of health impact and controlling availability of food items by agricultural protection policy and tariff policy). This research will verify the above hypothetical relations (arrows in solid line) by means of examining statistical data and other related information sources.
By elucidating the driving forces of the transition of consumption patterns of fats and oils in both countries, two distinctive case scenarios will be developed: “France scenario” and “Japan scenario” respectively. A comparison between these scenarios, accordingly, allows taking a step for generalizing and theorizing how individual driving forces affect dietary transition under a certain condition. This will also provide a clue to make a projection for the future dietary transition for the rest of the world.
2) Evaluate the environmental impact of dietary transition

After identifying the main driving force(s) of dietary transition in the case of fats and oils, this research attempt to evaluate an environmental impact caused by the dietary transition. To do this, we estimate how much land area would be necessary to produce a unit amount of fats and oils (i.e. we employ so-called “land footprint” approach). As for animal fats, we evaluate how much grassland required (for grass-fed animals) or how much land area necessary for feed production (for grain-fed animals).
Table 2. Average oil productivity of major oil crops in the world
Source: Okada et al. (2007), Current status and future vision of researches on oil crops for biofuels, Agricultural technologies, 62(3), pp.130-135. (in Japanese). 

According to Table 2, which shows an average productivity of major oil crops, oil palm is the most productive: its productivity is more than three times higher than other oil crops. To make it more precise, however, some more significant aspects as follows must be still taken into consideration:
  • Life cycle of crops: An appropriate adjustment is needed to make a comparison between perennial crops such as oil palm, which requires several years to be harvested, and annual crops such as rapeseed and soybeans.
  • Crop rotation: Since there is a risk of injuries by continuous cropping, annual crops are normally grown in a crop rotation cycle, which is the successive cultivation of different crops in a specified order at the same field. For instance, when considering soybean/maize rotation (1-year for soybean and subsequent 1-year for maize), annual productivity of soybean must be reduced by half.
  • By-products: After crushing oilseed, oil meal (a.k.a. oil cakes) can be obtained as a by-product, which is often used for feeding livestock as a protein source. This is in fact the reason why soybean oil is the second most dominant in the world, despite its low productivity compared with other oil crops (Table 2). The same is true for lards and tallows, as these are usually by-products of pig and beef meat. These positive impacts of by-products must be taken account.
We thereafter calculate how much land area in total has been virtually needed to satisfy the increased demand of edible fats and oils in the country up to the present. This approach enables us to quantify an impact on land use caused by the dietary transition and in turn to make a comparison of the impact in different countries such as France and Japan.