Fat, Fate, and Disease : Why we are losing the war against obesity and chronic disease (12 page)

There is another possible argument underlying the risks for people in difficult circumstances that emerges from a surprising source, evolutionary biology. Evolution is concerned with successful reproduction, not health or longevity. In many animals, when life is threatened, their rate of sexual maturation accelerates so as to ensure reproduction is achieved before death occurs. A respected evolutionary psychologist, Daniel Nettle from Newcastle, has pointed out that this might also be happening in humans. He argues that without a conscious change in behaviour there are evolutionarily embedded drivers that lead people in deprived circumstances to hurry up their lives. They reproduce early and more often, they
often have earlier puberty, and they make many choices in their lives that suggest they are not investing for the long term.

Unhealthy eating and storing excess energy now for threatening times later could well be part of an evolutionarily determined strategy to anticipate a difficult life-course. Similarly, the motivation to invest in lifestyle choices which only give a delayed advantage in the form of better health later would not be a logical strategy if life is expected to be short. There is no way of evaluating such a hypothesis and we really do not know to what extent unconscious human behaviour is informed by evolutionary echoes. But in other domains of understanding human behaviour and psychological health, the evolutionary perspective has been quite informative.

There are several critical factors that determine whether a family consumes a healthy diet. Firstly, they have to have the knowledge of what such a diet comprises. We will return to this in more detail elsewhere in the book. Secondly, they must have access to the components of such a diet, and lastly, they must have the funds to buy them. Looking at the situation of many families in the more deprived areas of cities in the developed world, we see immediately that none of these three conditions are likely to be met. The members of the family who make the decisions about what food they eat are very often not those who are best informed. Frequently, it is the children or the male head of the household who makes these decisions, and surveys have shown just how badly informed these individuals can be when it comes to nutrition.

Then if we look in the corner shops or small retail outlets which provide the basic necessities in such parts of our cities we find that they seldom provide much in the way of fresh fruit and vegetables, fish, brown bread, etc. All these items are just too perishable and too costly to bring to the shop in small quantities. So it turns out that the healthiness of a diet consumed by a family is very closely linked to how far they live from a major supermarket, whether they have transportation, and so on.

Finally, the reality is that healthy food is relatively expensive compared to junk food, or at least it is thought to be so. True, with
skill, care, and patience it is possible to make very healthy meals cheaply from simple ingredients, but all this takes just that—training and time—and these are often in short supply. In fact, lack of time is the most common excuse given by a range of adults for not engaging in much physical exercise, and yet the average person in the UK spends 30 hours a week watching television.

The issue is not only associated with poverty, however, because the choice to eat an inadequate diet can be quite culturally specific. In Japan, there has been a shift in the ideal body image. In the past, as in other Asian societies, a degree of plumpness was seen as a sign of a healthy, potentially fertile woman, one eligible for marriage. But as Western culture has invaded and replaced aspects of traditional culture, many young women have become obsessed with their body image and try desperately to lose weight to look like supermodels. This is made easier because the Japanese diet is traditionally low in carbohydrates, including sugars, and in fat. Additionally, an increasing number of young Japanese women are beginning to smoke. Smoking does not really suppress appetite, as is often believed, but it gives us something to do at a tea break at the office or when we feel in need of comfort.

So many Japanese women, especially in cities, tend to be thinner than would have been ‘desirable’ in past generations. But they should put on weight during pregnancy, shouldn’t they? Ideally, yes, but it turns out that many of them do not gain sufficient weight during pregnancy to support the optimal growth of their baby. Many obstetricians in Japan recommend only a low level of weight gain in pregnancy, even in women who are already extremely thin. Why?

The idea appears to have originated from an over-interpretation of studies of women who became pregnant during a famine in the Netherlands during the latter part of the Second World War. This famine,
known as the Dutch Hunger Winter, occurred when the Nazis imposed severe rationing on the Dutch population of the western Netherlands in reprisal for resistance activities. The famine lasted from late 1944 until the Allies liberated the Netherlands in 1945. Because good medical records were kept in some hospitals in the Netherlands despite the circumstances, these women and their children—and now even their grandchildren—have been the subject of detailed investigation of the long-term effects of famine during pregnancy.

The Dutch Hunger Winter studies have produced some unique data which have been very influential in showing the importance of fetal development to the risk of later developing chronic disease, an important concept which we will discuss in
Chapter 7
. But for some reason Japanese obstetricians focused on an idea, apparently derived from these studies but for which there is essentially no evidence, that eating very little in the first third of pregnancy protects the woman against the potentially dangerous disease of pregnancy, pre-eclampsia. Somehow this unsubstantiated idea migrated to Japan (although nowhere else), and obstetricians there began to advise women to restrict their weight gain in pregnancy. This has done nothing to prevent or reduce the risk of pre-eclampsia, but it has led to Japan being the only country in the developed world where average birth weight has fallen over the past two decades, especially in the major cities. The effect is surprisingly large—the average birth weight has fallen by almost 200 g in that time and, as we shall see later, this may have very important consequences for those people born at this time.

We can see here an all too familiar pattern where a coincidence of events and ideas conspires to produce a bad effect. This was another ‘perfect storm’—an idea from older studies which had never been properly substantiated, coupled with doctors deciding as a community to take action to prevent a particularly debilitating disease, plus women’s obsession with their body image in the late 20th century—and all this was happening in a population where, by and large, people adhere to the advice which they are given.

Finally, the women themselves were not likely to be concerned about this issue. In many cultures, it is believed that having a small baby is less risky for both mother and baby during labour. There is even a Japanese proverb which says, ‘It is better to start small and then grow big.’ As we will see later, this may not be such good advice.

While we were finishing this book a report from the Organisation for Economic Co-operation and Development (OECD) appeared. The 34 countries represented in the OECD range from the USA to Slovenia, from Norway to Chile. The Commission of the European Community also took part in the work which led to the report. The report is 265 pages and represents the work of many years of research and consultation. It contains the results of very detailed economic modelling of the cost-benefit ratio of various interventions, trying to put a price on non-communicable disease and to determine the economic value of some initiatives, such as educational ones, and weighing them against the likely savings for society in terms of reducing the cost of disease.

The authors of this report have arrived at some apparently definition conclusions. One is that the most effective way of reducing the burden of obesity in adults is to arrange for them to have repeated consultations with a health professional to keep them up to the mark with their diet and exercise programmes. However, this is also a very expensive intervention and cannot be made widely available even in developed, let alone developing, societies. The report—as with others like it, although we have to say that this is an extreme example—hardly refers to the variation between people in their propensity to become obese or to lose weight, and no consideration is given to how differences in metabolism between people develop. Sadly, it appears to have been written without consideration of the reality of human variation and biology.

And recent reports from the World Health Organization do not do much better. Indeed it is extraordinary how many of the so-called experts on the problem seem to ignore the science underlying the problems and go straight to their favourite solution, which is always familiar. It is the same old tale: give humans the chance and they will all be guilty of the sins of gluttony and sloth, with the consequences of obesity, diabetes, and cardiovascular disease—end of story. But, as we shall see, it is not.

We were concerned to read in the OECD report that the determinants of obesity divide into three components. The first are supply-side factors—by which the authors of the report mean the food industry, advertising, and production techniques for highly processed foods. Secondly, there are government policies including those on public transport, taxation, and the provision of recreational facilities for exercise. And thirdly, there are changes in working conditions that lead to reduced physical labour and higher stress levels. Where is the biological perspective here? It is missing. The approach is like trying to solve the problem of why your car will not start without knowing about starter motors and fuel pumps and batteries—but insisting that there must be a problem with the key. Throughout the report, which goes into quite sophisticated socio-economic analysis, the underlying belief is that people who don’t eat excessive amounts of unhealthy foods and who undertake regular physical exercise don’t usually get very fat.
Therefore
the answer to the problem of obesity is to prevent people from over-indulging themselves and to make them exercise. Nowhere is the possibility even considered that this is not strictly logical and that the truth might be somewhat more complex.

How we respond as individuals to a changing world and to our morphing body shapes is not straightforward. Despite the apparent simplicity of the energy equation, dieting and exercise do not solve
the problem because many people are unable to lose much weight, or if they lose weight they soon put it back on. Furthermore, motivations vary between societies because perceptions of body shape are very different across cultures and genders, and are influenced by circumstances.

We need to conclude this chapter by thinking more about public opinion and the politics of obesity, diabetes, and cardiovascular disease. To illustrate the argument, it is worth returning to the public health anti-smoking initiative. Research has shown that the reduction in smoking in some parts of the population has been heavily influenced by taxation, and by legislation to ban smoking in public places. But while these measures have been enormously helpful, they have been politically possible only because of another motivation. And that motivation is stigmatization.

Society has vilified the smoker, and smoking in public has become ‘unacceptable’ behaviour. Humans evolved to live in social groups and no one can live comfortably within a group where they suffer social approbation. That is why smoking in Western countries is now confined largely to groups such as adolescents, who are used to challenging social norms and facing potential approbation—they want to be seen as outlaws and rebels. This is probably more true of young men, but young women too are increasingly likely to smoke, especially in parts of the developing world where the tobacco industry is specifically targeting advertising at them.

We worry that there is a growing tendency among some public health practitioners to adopt a similar strategy with respect to obesity—that is to stigmatize those who are obese and to vilify the food industry or try to ban certain food components. Some commentaries are adopting an increasingly shrill tone, declaring that the problem is all about fructose or all about trans-fats or all about vitamins. It is suggested that a simple ban like that on smoking could work. Ban McDonald’s and all will be well. Ban soft drinks and all will be well. There are many reasons why this will fail—and at the
end of the campaign the very people who need most assistance will still be obese and at still greater risk of disease.

Any solution will be somewhat complex. We have a pipeline of food supplies that is very different from that of our ancestors. Food is now not simple—increasingly, our diet is not what comes out of the ground, off the tree, or from an animal. More and more foods are manufactured from extensively processed ingredients, loaded with additives, and having undergone chemical changes. The mixture of fats and carbohydrates we consume and our sources of protein are very different from what they once were. And more changes take place all the time, given the power and size of the food industry on the one hand and the way we want to live our lives on the other. Before television came along we had no need for TV meals—do we really need them now? Not really, but we like the convenience.

Our argument is that, if we are to tackle the problem of obesity, diabetes, and cardiovascular disease effectively, several parts of the equation are missing. We will discuss other gaps later but an important one is quite simply, knowledge. Hardly anyone, wherever they live, has a real understanding of what they are eating and what they should eat. The pace of change in the nature of the food supply and the way we live our lives means that for many people traditional family-based knowledge about food is insufficient. The food our parents bought (or grew) and the way that they cooked and served it bear little relation to our food pipeline today. And we have already seen how poor eating and other lifestyle habits can run in families, so leaving the imparting of knowledge about healthy nutrition only to parents is more likely to reinforce disadvantage in those who do not consume a good diet now.