Worldwide obesity has more than doubled since 1980 and most of the world’s population now live in countries where overweight and obesity kills more people than underweight [45, 75]. Research on the relationship between economic development processes and health has identified several competing structural explanations for rising body mass index (BMI) including globalization processes, economic development and women’s changing role in society that likely affect changes in underlying behavioral mechanisms. Previous research has not systematically tested these different explanations for the global rise in obesity.
A growing body of literature has drawn attention to the ways that economic globalization, particularly trade liberalization, has contributed to global weight gain by facilitating the diffusion of obesogenic products such as sugar-sweetened beverages and packaged foods to low and middle income countries (LMICs) [2, 10, 17, 18, 28, 29, 37, 46, 64, 65, 72]. In addition, other elements of globalization apart from economic globalization may contribute to rising obesity rates globally. Cultural globalization, or “Westernization,” may encourage the consumption of fast foods like McDonalds to appear more “modern” [57, 73]. This may be less due to economics and more due to the cultural appeal of Western lifestyles, which can contribute to obesity as people abandon local cuisines for Western-influenced diets [49]. These “world systems theory” accounts place the explanation for countries’ widening waistlines largely on factors external to the country – i.e., international trade regimes that have allowed the entry of transnational food corporations into emerging economies driving increased consumption of unhealthy foods and ideational lifestyle diffusion [58].
However, an alternative explanation for the global rise in obesity is that countries are experiencing domestic “nutrition transitions,” or the shift from a primarily plant-based diet to a meat and processed food diet associated with weight gain and chronic illnesses [50, 52]. Even in the absence of increased exposure to global markets or images of the Western consumerism, burgeoning middle classes in countries may increase demand for a richer diet and prepared foods, including increased consumption of potentially unhealthy local foodstuffs. Modernization is also believed to set in motion a set of additional normatively positive developments that may also improve health in LMICs including urbanization, women’s rights and democratization [55]. In this “modernization theory” view of obesity, development inexorably leads to health transitions, including the rise of unhealthy lifestyles as people have more disposable income [4, 22].
However, development scholars have debated over whether modernization is a linear process, giving rise to immediate health improvements, or whether it forms more of a curvilinear, inverted-U shape relationship whereby the overall burden of disease may increase before declining owing to a double-disease burden [53, 54]. Moreover, technological diffusion facilitated by globalization may also serve to reduce disease burden or compress health transitions as health innovations may be more rapidly transferred and scaled-up in LMICs [53]. Thus, globalization may not be primarily a force for harm, foisting insalubrious products and habits on LMICs, but can also serve to transfer knowledge and leapfrog stages in development.
If modernization theory is correct, a linear relationship between GDP growth per capita and BMI should be observed whereas if dependency theory is correct, greater integration into the global economy and Western culture should contribute to more obesity. However, it is also possible that the relationship between economic development and weight is not linear and that at low levels of development weight increases rapidly but then levels off with higher levels of development.
Though several studies have recently examined cross-national determinants of overweight/obesity in relation to globalization processes, previous studies have not attempted to explicitly test competing theories regarding the relationship between economic development and health across a full set of countries over a long time frame [8, 10, 11, 24, 35]. We test these different theories for the rise of global obesity rates using a longitudinal dataset of mean body mass index from the Global Burden of Metabolic Risk Factors of Chronic Diseases study and data from the Quality of Government dataset (QoG) that covers 190 countries from 1980 to 2008 (see Conceptual Model, Fig. 1). We improve on previous studies methodologically by using multiple imputation for missing values to ensure a balanced panel for all countries.
Economic development, modernization theory and health
At low levels of development, health is generally thought to improve linearly with wealth [53, 54, 74]. In other words, as countries grow wealthier, health should improve in tandem. Proponents of this classical version of modernization theory suggest that economic growth and development should set in motion a series of normatively positive economic, social, cultural and political changes that would, interacting synergistically with one another, produce a “virtuous circle” of increasing living standards, social mobilization, democratization [36, 59] and improved health and human well-being [21]. Building on assumptions underlying modernization theory, classical demographic theory predicts a linear, secular decline in disease risk as wealth increases generating an epidemiologic transition from a high birth, high mortality dynamic driven by infectious diseases to a low-birth, low-mortality dynamic with death stemming largely from chronic illnesses [47]. As it pertains to nutrition and weight gain, classic works by Fogel [20] and McKeown [42] suggest that nutritional improvements (improved diet and synergies with infectious diseases) played a primary role in mortality reductions over the nineteenth century. Moreover, Fogel [21] suggests that improved nutrition has also contributed to improvements in human capital, which has served as a primary force promoting economic growth in the long term. However, while undernutrition may harm health, and adequate nutrition may be necessary for growth and reduced infectious-disease related mortality, recent attention has turned towards the role of overnutrition in contributing to the growing burden of chronic diseases in LMICs [65]. This conversion from a primarily plant-based diet to a meat and processed food diet associated with weight gain and chronic illnesses is referred to as the “nutrition transition” [51]. The global nutrition transition is believed to be contributing to rising obesity rates globally as well as increases in rates of chronic illness for which LMICs are believed to be unprepared [56].
Modernization theory might also predict BMIs to increase through the additional mechanisms of urbanization, women’s empowerment, and democratization. According to modernization theory, economic development is believed to unleash a series of normatively positive developments [36, 59] including industrialization, urbanization, increasing education levels, social mobilization, and the emergence of civil society- a progressive series of social change that ultimately culminate in democratization [55]. Of these processes, urbanization has previously been examined and found to be associated with rising obesity levels [7, 50, 51, 63]. People living in urban areas are believed to consume diets distinctly different from those of their rural counterparts and the general shifts in their diets enhance energy and fat density of foods consumed and may affect patterns of physical labor and activity [51].
Democratization might also have an impact on obesity, though it is not clear what the direction of the relationship might be. On the one hand, previous research has found that democracy reduces famines by ensuring government accountability and responsiveness [61]. Improved food security and nutritional status of the population might lead to higher BMIs. Countries that are democratic might adopt more consumer protection and regulatory policies that could also shield the public from obesogenic foods. On the other hand, there is little evidence presently that democracies have been more effective at protecting the public and citizens may not support against anti-obesity policies that are viewed as paternalistic.
Economic development may also contribute to changes in women’s role in society through changes in social relationships and family structure due to urbanization, labor force growth in industry and service [48]. However, the exact nature of the relationship between modernization and the development of women’s rights remains contested and others stress the importance of reducing patriarchal systems of oppression regardless of level of economic development [14]. Previous research has linked women’s labor force participation to rising obesity rates [1, 3, 5, 26]. Though the mechanisms are not well understood [5], working women may have less time to prepare healthy meals and may rely more on prepared foods [3]. Women that are more empowered socially and legally may also experience less constrained gender roles that tie them to traditional homemaking tasks including cooking.
However, other research has pointed to evidence of non-linearities in the relationship between wealth and health. While proponents of classical modernization theory view each of these processes as advancing in a linear fashion, critics of classical modernization theory have asserted that modernization is not in fact a linearly progressing, peaceful process, but rather one that results in social upheaval as a loosening of social controls with the decline of religious and traditional sources of meaning creates moral and normative vacuums [32, 60]. Adherents to this revised version of modernization theory, while still viewing development as unfolding in a relatively evolutionary and teleological manner, regard the process of economic development not as one unleashing a “virtuous circle,” but instead a “vicious circle” of rising expectations coupled with the inability of the state to respond to the growing demands of an increasingly engaged but thwarted populace. For instance, Szreter [70] has observed that rapid economic growth may actually cause health to get worse before it gets better generating more of an inverted-U shape relationship between development and disease burden. He attributes this to what he calls the “four D’s”- “disruption” of traditional ways of doing things, increasing relative “deprivation” followed by increases in “disease” and “death.”
In a similar vein to Szreter’s inverted U-shape relationship between development and health improvements, but operating at the individual level, the literature on the social determinants of health makes a distinction between diseases associated with absolute poverty and diseases that tend to be associated with relative poverty (e.g., [38, 39]). Examples of diseases associated with absolute poverty include malnutrition, diarrheal disease, and what are now considered to be neglected “tropical” diseases. These diseases are believed to be subject to a threshold effect such that once an individual is no longer exposed to the conditions that give rise to these diseases (i.e., vectors and disease hosts associated with a lack of sanitation, potable water, adequate nutrition, etc.), these diseases tend to decline on their own [38]. These diseases of poverty do not form social gradients and should in theory decline linearly with economic development.
By contrast, diseases of affluence associated with relative poverty should increase with development and then level off. Present day middle-income countries are beginning to experience what has come to be known as the “double disease burden”- or the coexistence of undernutrition and overnutrition-related non-communicable chronic diseases [67]. Risk factors associated with the lifestyles of a growing “leisure class” including changes in diet (the nutrition transition), smoking, and exercise that initially accrued to the rich in now developed countries are only just now emerging in the burgeoning middle classes of developing countries, whereas in rich countries the gradients in these lifestyles reversed decades ago [76]. Thus, middle income countries should have the highest overall burden of disease and one would expect obesity rates to be the highest in middle income countries that are presently in the midst of the nutrition transition.
Globalization, dependency and health
Modernization theory and health transitions theories grounded in this view have been criticized for their teleological assumptions and linear world view as well as being undermined by a growing set of examples of countries that have not advanced on such a path. These explanations are further viewed as putting too much agency in the hands of countries and paying too little attention to dynamics in the international economy that function to perpetuate underdevelopment in low income countries. In contrast with modernization theory, dependency and world systems theories comprise a class of “radical” development theories, which suggest that poverty and underdevelopment is not so much the product of countries’ own making, but rather is largely the product of external exploitive factors acting upon countries [6, 16]. Though a full review of the literature on these theories is beyond the scope of this manuscript, according to this class of theories, the developing world was and continues to be dominated economically as well as politically by external centers of power. Debt, trade, and foreign investments pose negative effects on their populations’ health in this view.
While globalization and dependency/world system theories are arguably distinct, we, along with others, view the critiques of globalization as they pertain to health in LMICs as similar to criticisms advanced in the literature on dependency/world systems theory [27, 30, 34, 41]. Critics of globalization’s effects on health, for instance, have pointed to the role of “Big Food” in diffusing obesogenic food products globally. According to this view, the saturation of markets in developed countries, and the fact that people spend 20% of their income on average on food globally, has stimulated Big Food to seek global expansion [66]. Multinational food and beverage companies with concentrated market power have gained rapid entry into markets in low- and middle-income countries (LMICs) as a result of mass-marketing campaigns and foreign investment, principally through takeovers of domestic food companies. Three-fourths of world food sales involve processed foods, for which the largest manufacturers hold over a third of the global market [66]. In this world systems view, the flooding of markets in LMICs with highly processed, low-quality food stuffs is what can primarily account for recent increases in obesity rates in LMICs rather than domestic economic development processes per se.
A related explanation relies more heavily on the cultural appeal of Western lifestyles. As mass marketing diffuses Western processed foodstuffs including McDonalds, coco-cola and prepared foods, residents of LMICs begin shifting from traditional, local foodstuffs to a less healthy, stylized Western diet high in fat and sugar and low in nutrients. Through the spread of ideas, information, and images glorifying certain eating and leisure time activities, the public in LMICs may be influenced to adopt obesogenic behaviors. In both cases, increases in global BMI are viewed as resulting from international markets and diffusion processes and are less influenced by domestic social changes associated with economic development.
To test these different theories for the global rise in obesity, we assemble a longitudinal dataset comprising measures of mean body weight, economic and cultural globalization, GDP per capita, women’s empowerment and democracy for 190 countries over a 30-year period (1980–2008).
Existing cross-national evidence on globalization, development and obesity
Several recent studies have examined cross-national determinants of overweight/obesity in relation to globalization processes [8, 10, 11, 24, 35]. Two studies, De Vogli et al. [10] and de Soysa and de Soysa [11], come closest to the present analysis employing cross-national time series analysis.
Drawing on a sample of 127 countries over the period 1980–2008, De Vogli et al. [10] et al. analyze the effects of economic globalization on BMI using time-series cross-section analysis. They find that economic globalization predicts increases in BMI with modest effect sizes (coef. = 0.008, p < 0.05) after adjusting for GDP per capita, which is also found to positively predict BMI. However, they employ few controls (only urbanization, proportion living in poverty and GDP per capita) and their sample excludes countries with missing data reducing country variability and sample size. They also do not disaggregate between male and female BMI.
de Soysa and de Soysa [11] examine the relationship between measures of economic and social globalization on childhood BMI measures (age 2–19) over the period 1990–2012 using cross-national time-series analysis with fixed effects across a sample of between 120 and 180 countries depending on the model. In contrast with De Vogli et al. [10] they find a negative relationship between economic globalization and childhood BMI and they find no relationship between social globalization and childhood BMI. They further find that several component parts of economic globalization such as trade openness, FDI flows, and an index of economic freedom reduce weight gain and obesity among children and youth leading them to conclude that “local-level factors possibly matter much more than do global-level factors for explaining why some people remain thin and others put on weight” [11]. While their focus on childhood obesity is a strength as this is the most likely age cohort to have been affected by the past three decades of globalization and associated lifestyle changes, their focus is more restricted as it does not encompass later life obesity rates, which would more plausibly be linked rising rates of chronic disease in older adults. The time frame and country sample is also more restricted. Both studies employ BMI data from the Global Burden of Metabolic Risk Factors Study and use the KOF globalization index as a metric for economic globalization.
Lawson et al. [35] also use a cross-national sample of 135 countries between 2000 and 2009 to examine the relationship between a measure of “economic freedom” and adult BMI. Economic Freedom of the World (EFW) index captures nations’ degree of reduced taxation, sounder property rights, stable money, freer trade, and more limited regulations score higher on this index. They find that economic freedom is associated with modestly higher BMIs for men (but not women) in developing nations. As with the previous studies, their country sample and time frame are more limited.
Finally, one other study has drawn on samples of individual-level data to examine the relationship between adult obesity (measured at the individual level) and macro-level measures of economic social and political globalization. Covering 56 countries, Goryakin et al. [24] find that economic globalization reduces obesity among adult women while social and political globalization increase obesity, with political globalization having the largest effect.
This study builds on this previous research by introducing several additions that foster greater confidence in the results. First, the paper lays out an explicit theoretical framework and tests additional variables not included in previous analyses that may influence global obesity trends including women’s empowerment, measures of more proximal dietary and physical activity mediating mechanisms and allows for a curvilinear relationship between GDP and BMI. Second, the paper includes a wider set of countries by employing multiple imputation to avoid selection bias and employs fixed effects to remove unobserved factors that differ between countries and are constant over time.