Why are we fat? Discussions on the socioeconomic dimensions and responses to obesity

Weight gain does not affect everybody in the same way. Not everyone who is overweight is ill because of it and not everyone who is overweight has a poor diet. The way in which people consume food and manage their health varies according to many factors ranging from socioeconomic status, gender, age and ethnic origin as well as the interaction between micro- and macro-structural factors that change from one society to another [22].

Across the European continent, obesity has been growing in prevalence, with particular concern focused on children [13]. The annual rate of increase appears to be upward; from around 0.2% during the 1970s to 0.8% in the early 1990s [3]. There are important differences within and between countries. Croatia and Finland have the highest prevalence among males older than 15 years (around 22%), while Uzbekistan and Norway have the lowest prevalence (around 6%). The relative importance of the specific factors which explain such wide variance are difficult to establish since national wealth, local dietary patterns, culture and other factors which appear to be driving this trend, appear to interact in complex ways.

In Spain, the location of the ESOF meeting, variables such as age, social class, sex, and region of habitation, for example, all appear to be related to obesity prevalence [23]. Overall prevalence of obesity among adults is 15.5% (15.7 and 15.4% among men and women, respectively; Figure 1), and this percentage increases with the age, from 5.5% at 18-24 years old to 27.3% at 65-74 years. With respect to social class it increases from 10.4% among the highly skilled to 19.5% among the unskilled. In the case of women, it increases threefold from 6.9% among the highly skilled to 21.8% for unskilled. Pensioners have the highest rate of obesity (23%) followed by homeworkers (20.6%). Differences also expressed regionally. The prevalence ranges from 11%-12% in La Rioja, Madrid and the Balearic Islands to 18%-19% in Murcia, Andalusia or Extremadura [23].

Among the Spanish children (2 to 17 years old) the numbers are also of growing concern (Figure 2). The highest prevalence is for children between 5 to 9 years old (15.4%) and those in the range of 2 to 4 years old (15.3%). Parents' professional background is related to prevalence, increasing from 4.4% for the more skilled to 12.2 and 11.4% for those less skilled. In terms of territorial differences, the highest prevalence is in the Canary Islands, Ceuta and Melilla, Comunidad Valenciana, La Rioja and Andalusia (from 12 to 16%) and the lowest rates are found in Asturias, Castilla la Mancha, Galicia, Madrid and Basque Country (from 4.5 to 5.5%) [23].

It is a metabolic rule that when we consistently overeat we put on weight: it therefore follows that dietary intake and physical activity matters [24]. However, changes in diet and levels of physical activity always occur in historical and social context, a fact which is often ignored [25]. The result is that behavioural and biomedical discourses emphasise proximate causation and individual responsibility [26], which, in turn, limits the possibilities of public health action [27]. Proximate causes include dietary patterns, levels of physical activity, and genetic factors. Specialists stress the consequences of reductions that have occurred in everyday activity, such as walking, the time spent in sedentary pursuits and patterns of body weight in parent and child. Advice from experts therefore centres on changing 'disordered' lifestyles and consumption patterns in order to promote healthy habits, guided by general practitioners, pharmacists and others, increasing the responsibility of individuals through taming their appetites and encouraging the self-regulation of appetite. It follows that explanations of obesity found in the media, and refracted into political discourse, focus on a person's choices and lifestyle in their immediate environment (behavioural frame), although lately there is an increasing recognition of the importance of the environmental factors which simultaneously constrain mobility and stimulate the intake of high fat, high energy foods (systemic frame) [27]. As a consequence, policies focus on the individual and highlight the role of individual choice in diet or participation in physical activity as the key to health improvement. The principal recommended mechanism of change is educational, including family recognition that the problem actually exists, and encouragement towards healthy lifestyles, along with some environmental improvements, such as food labelling [28].

Given that there is little evidence that the favoured social marketing approach, in any of its different formats, has halted overall obesity trends [29, 30], the question might be as to why the focus on educating individuals remains dominant to prevention efforts. The answer may be that alternative explanations, which by implication require a much broader range of policies and actions, are too economically and politically challenging.

In more market-oriented societies, it has been suggested that social and health problems take on a more common character [31]. In the case of obesity there are numerous commercial opportunities. For instance, functional foods, dietary advice and diet book publishing have risen rapidly. In the UK, the sale of functional foods has risen from £134 million in 1998 to £1.7 billion in 2007 [32]. While large investments have been made by pharmaceutical companies in the field of anti-obesity drugs, market growth does not follow the growth of obesity prevalence but rather the scope of reimbursement for pharmacological management, which in many countries remains limited [33].

To the dietary recommendations launched by health professionals and public authorities to promote health, the numerous and often contradictory messages distributed through market channels must be added [34]. Advice in favour of the optimum diet and normal body weight has been adopted by the health and 'body care' market. Advertising and marketing campaigns offer clues for understanding the role of the food industry, aided by scientific and technological innovations. The marketing industry is the creator, par excellence, of the rhetoric of "well-being" and the commercialization of the term "health", an umbrella concept that subsumes a broad range of other concepts: pleasure, beauty, convenience and mental health [35]. Products are advertised as "light" or "free" - as in cholesterol-free, sugar-free, and fat-free. In the same way, products "with" - fibre, lactic acid bacteria, minerals, fatty acids -represent a new generation of products designed to cater to our perception of well-being and health [36].

For all these reasons, it is difficult to separate interests related to health and interests related to commerce in biomedical discourse [37]. Thus, at the same time that the medical establishment warns against overweight as a threat to health, the consumer and medical economy is inundated with food products of doubtful nutritional quality, diet plans, weight loss drugs and weight loss surgery.

Is consumer choice driving global or national trends in population weight gain, and underlying the independent consumption decisions of millions of people, or are there other, less visible, but nevertheless real, explanatory factors at work? While individual consumer choice provides the enduring narrative circulated in policy circles and the media, attention to structural causes (and thus structural solutions) linked to the economic and cultural identity of society is given less prominence. Structural types of explanation for obesity focus on long-term economic and social policy trends - some of which take a global form [31] and the changing context of consumer choices.

One approach for explanation begins by analysing changes within the food supply chain and the reshaping of the way in which food is produced, formulated, priced, marketed and consumed. Following the lead of the USA, farming legislation has resulted in ever-cheaper basic ingredients available to food manufacturers and retailers, boosting portion sizes as well as consumption of high fat, energy dense foods [38]. Since the 1970s the European Common Agricultural Policy, has balanced subsidies to primary producers with economic liberalisation in markets, particularly in food manufacturing, food services and food retailing. Whereas the former boosted production levels, the latter introduced new capital into the food manufacturing and retail segments, profoundly altering food provisioning systems [39]. The impact has been dramatic. Traditional diets, in particular 'Mediterranean Diet' of Spain, Italy, Greece and Malta - previously much praised by nutritionists - has given way to new dietary regimes containing much higher levels of saturated fats, salt and sugars. Such trends extend well beyond Europe and may be resulting in a global culture of food [40]. Even so, apparently homogenizing forces produce outcomes which vary according to national or cultural context [41].

A second type of policy analysis aims at encompassing these economic and business realities, public policy and cultural factors, implying the need for scientific collaboration across different research disciplines (as well as co-ordination and collection of different types of knowledge) together with detailed understanding of the interplay of local, regional, national and global factors [42‐44]. A third focus points to the imbalance of power between the public good and corporate freedom [45] and raises questions over current understandings of health and the nature of the economical interventions needed to support health [46].

If these perspectives add to our knowledge of structural factors, there remains open the need to construct an integrated and holistic perspective which can draw upon not only the biological and physiological aspects of obesity and its social, economic and environmental determinants, but which also examines the feedback between the conditions which are shown to influence health to those which affect the natural environment. In part, the formulation of this new approach has already begun. An ecological perspective has already been established within the prestigious US Institute of Medicine [47], while a specifically ecological model was formulated to examine obesity [48]. An ecological approach is also present within the British government's Foresight Study of obesity [49]. It has been suggested that tackling obesity and tackling climate change can both be characterised as 'ecological' in form and share a number of similar underlying drivers and characteristics [29, 50]. Both have been years in the making, both involve the interplay between similar factors - overuse of energy derived from fossil fuels and underutilisation of human energy, overproduction and waste, and lack of sustainability- and both, in public policy terms, are insufficiently recognised and require long term framework of action, implying a thorough redirection of society. It is agreed that steps towards low-carbon living (including changes in consumption patterns or green-designed cities) have health benefits that will improve quality of life by challenging diseases arising from affluent high-carbon societies, such as obesity [50]. A full response requires a holistic global approach, but this fact should not be a reason to delay changes that are beneficial to human health and can be implemented immediately [50].