Nutrition transition in Thailand: An empirical study using night-time lights : A thesis submitted in partial fulfilment of the requirements for the Degree of Doctor of Philosophy at Lincoln University

Abstract

Nutrition transition is defined as changes in dietary patterns. Recently, researchers have observed nutrition transition in developing countries experiencing higher incomes and urbanisation. This study aims to better understand this phenomenon in Thailand by using econometric analyses. We use the Quadratic Almost Ideal Demand System (QUAIDS) model to investigate changes in food expenditure over time, and the direct approach, a reduced-form model, is used for nutrient intake. The study uses food expenditure and nutrient intake data from the Thailand Socio-Economic Survey (SES) compiled by Thailand’s National Statistical Office (NSO). This study also investigates how urbanisation changes patterns in food expenditure and nutrient intake using satellite images of night-time lights obtained from the National Oceanic and Atmospheric Administration (NOAA). The study first examines why Thai households change their dietary pattern. The results show that nutrition transition is specifically linked to dynamic changes in household demographics and geographic characteristics. Household demographics include household size, household composition and women’s labour force participation. These household demographics with geographic characteristics clearly explain the shift in dietary patterns. Interestingly, women participating in the labour force increases the frequency of home-cooked meals, leading to better nutrition and wellbeing for Thai families. Thus, demographics and geographic characteristics are as equally significant as economic factors in the analysis. Second, this study discusses how changes in dietary patterns have occurred in Thailand. Changes in food and nutrient intake patterns are complex. Consistent with the framework for nutrition transition, food preferences have shifted towards animal-source foods, sugary products and ready-cooked food. However, traditional staples, such as grain and cereal products, remain a dominant source of calories. Healthy foods (such as fruit and nuts) are no longer a luxury, reflecting higher familiarity with these foods among Thai households; nutrition inequality materializes in Thailand with less access to these healthy foods among the poor. Sin goods (such as sugary products) are more desirable, particularly in households with children and in poor households. Together, the results confirm that nutrition transition is happening in Thailand. Finally, this study investigates the effects of urbanisation on nutrition transition. The results indicate that night-time lights highlight the role of urbanisation in shaping patterns of dietary intake; increased urbanisation stimulates food diversity. This makes the demand for food and nutrients less income-elastic, which can create a permanent change in some food preferences. Urbanisation, therefore, drives new eating habits in Thailand.