‘We don’t know very much about what people consume, actually,’ Imamura tells me, disarmingly, sipping his black coffee. ‘Assessment of diet is very difficult.’ Almost all the data we have on what people eat is based on market figures: what commodities come into the country, or how many packets of an item people buy in any given year. This data on supply and production is used as a proxy for what people actually eat. It is useful for mapping big changes in our diets over time – the rise of salmon and the fall of herring, say. Often, food supply data reveals big truths about what we eat that are invisible to us in the daily bustle of shopping and cooking. Much of what I’ll tell you about food in this book will come from market data because often it’s the only hard data available.
But this kind of market data has flaws: for one thing, it offers only a national average, and for another, it does not tell you what happens to the food after it enters the home. Did the consumer steam that bag of green beans and eat them with grilled sardines? Or leave it to rot at the back of the fridge?
Another method of measuring diets is to ask people what they eat, whether over a 24-hour period or in a seven-day diary. Imamura tells me he much prefers survey data to market data because it gives a more detailed picture of how consumers actually behave around food. The snag is that one of the ways we behave around food is that we lie about it: No, I never bought and ate those extra-cheesy nachos. Yes, I eat five fruits and vegetables a day, every day. We also forget things, like that Snickers bar we devoured in haste between meetings.
One way to get around this problem of accuracy is to measure biomarkers in the human body itself, like forensic scientists analysing a corpse. In recent years, epidemiologists have started searching for traces of our diets in blood serum, hair samples and even toenail clippings (toes are used instead of fingers because they are less exposed to outside environmental contamination). Toenail clippings are apparently the best way to measure levels of the mineral selenium in the body – a detail nutrition researchers are interested in, since low selenium correlates with type 2 diabetes and childhood obesity.
The most versatile and commonly used biomarker to determine dietary intake is urine. Unlike toenails, which take weeks to grow back, urine is – how to put this delicately? – endlessly renewable, and it reveals traces of more different foods than any other measure. We haven’t quite reached the point yet where a sample of your urine could tell a researcher that you ate spinach gnocchi for lunch and pumpkin risotto for dinner, but that day may not be far off. In the meantime, urine has most often been used to measure how much salt we eat. Imamura and his colleagues looked at 142 surveys that measured sodium levels in urine, providing data on salt consumption for the majority of adult humans on the planet.11
At the time of writing, Imamura’s study is the most complete snapshot we have of diet quality on a truly global scale as it relates to patterns of ill health. In all, the researchers managed to find data to cover 88.7 per cent of the adult population of the whole world. From this, they built up a picture of what we eat from two different angles: on the one hand, how much healthy food countries eat and on the other hand, how much unhealthy food.
A person may enjoy eating a slice of fresh melon but also enjoy munching on greasy fried onion rings. Countries, too, have contradictory tastes. Since 1990, the planet’s consumption of ‘healthy’ items has undoubtedly been growing, but this does not mean that people necessarily have a healthy pattern of eating. Take fruit. Since 1990, world vegetable consumption has remained static but the world’s fruit intake seems to have gone up by an average of 5.3 grams per person per day. For people who can afford to buy it, fresh fruit, from grapes to watermelon, has become one of the world’s favourite snacks. Fruit is expensive and it’s one of the first things parents buy as a treat for their children when they start to have disposable income. The rise of fruit gives credence to the fairy story about modern food (setting aside the fact that modern fruit is often not as nutritious as fruit used to be). Out of 187 countries, all but twenty or so have increased their intake of healthy foods, especially foods such as fruit and unsalted nuts which are eaten between meals.12
But Imamura’s paper also supports the food horror story. The data clearly shows that diets high in sugary drinks, trans fats and processed meats became much more common in the world between 1990 and 2010. In 2010, around half the countries in the world were eating a diet higher in unhealthy items than in 1990, often drastically higher. The prevalence of unhealthy items in our diets is increasing more rapidly than our consumption of healthy foods. But it is not increasing everywhere to the same extent.
The biggest surprise to come out of the data was that the highest-quality overall diets in the world are mostly to be found not in rich countries but in the continent of Africa, mostly in the less developed sub-Saharan regions. The ten countries with the healthiest diet patterns, listed in order with the healthiest first, came out as:
Chad
Mali
Cameroon
Guyana
Tunisia
Sierra Leone
Laos
Nigeria
Guatemala
French Guiana
Meanwhile, the ten countries with the least healthy diet patterns, listed in order from the bottom up, were:
Armenia
Hungary
Belgium
USA
Russia
Iceland
Latvia
Brazil
Colombia
Australia
The idea that healthy diets can only be attained by rich countries is one of the food myths, Imamura says. He found that the populations of Sierra Leone, Mali and Chad have diets that are closer to what is specified in health guidelines than those of Germany or Russia. Diets in sub-Saharan Africa are unusually low in unhealthy items and high in healthy ones. If you want to find the people who eat the most wholegrains, you will either have to look to the affluent Nordic countries where they still eat a lot of rye bread or to the poor countries of southern sub-Saharan Africa, where a range of nourishing grains such as sorghum, maize, millet and teff are made into healthy main dishes usually accompanied by some kind of stew, soup or relish. Sub-Saharan Africa also does very well on consumption of beans, pulses and vegetables. The average Zimbabwean eats 493.1 grams of vegetables a day, compared with just 65.1 grams for the average person in Switzerland.13
It was Imamura’s conclusion about the high quality of African diets that ruffled feathers in the world of public health. What about African hunger and scarcity? Zimbabweans may eat more vegetables than the Swiss, but there is more to health than vegetables, given that life expectancy in Zimbabwe in 2015 was just fifty-nine years of age compared with eighty-three for the average Swiss person. Some scientists argue that the low score for unhealthy foods in some African and Asian countries is actually a sign of diets that are ‘poor’ in various ways. If the people of Cameroon consume low amounts of sugar and processed meat, it is partly because they are consuming low amounts of food all round.14
Imamura does not deny, he tells me, that the quantity of food available is very low in some of the African countries, but adds, ‘That’s not the point of our study. We were looking at quality.’ His paper was predicated on the assumption that everyone in the world was consuming 2,000 calories a day. Imamura was well aware that is far from the case in sub-Saharan Africa, where the prevalence of malnourishment is around 24 per cent according to the Food and Agriculture Organisation. But he and his colleagues wanted to isolate the question of food quality from that of quantity. Traditional public health nutrition, he observes, was so fixated on the question of hunger that it paid too much attention to the quantity of food people had access to without considering whether the food itself was beneficial for human health.15
Africa’s hunger can easily blind us to the sheer quality and variety of food that people enjoy in much of the continent. The findings of Imamura’s paper came as no surprise to Graeme Arendse, a South African journalist at the Chimurenga Chronic, a magazine celebrating pan-African culture. In 2017 Arendse helped put together a special food issue of the magazine which challenged the Western idea that African food was all about deprivation and suffering. On a sunny winter’s day, sitting in his offices in Cape Town above the pan-African market in the city centre, Arendse tells me that ‘this story of scarcity is not true’. Arendse sees traditional African food as deeply diverse, with much of it very healthy. A short walk from his office in Cape Town, Arendse can pick up a takeaway of fish and brown rice at a Malian place where he likes to go. Other days, when the mood hits, he goes to a different café to buy a bowl of Nigerian egusi soup made from melon seeds with seafood and bitter greens, for the same price as a fast food meal from McDonald’s.
Arendse worries that unless traditional African cuisine with its soups and stews of many kinds is celebrated more, it will lose out even more to the fast foods and convenience foods that he notices becoming so popular now in South Africa. On the bus into work, in just the past couple of years, he has started to see some commuters breakfasting on crisps and cans of cola. ‘I never saw that in the past.’
Dietary patterns are getting rapidly worse in much of Africa, including South Africa. In recent years, monied South Africans have abandoned the old dinners of mealy maize and have started to drink bottles of sparkling mineral water and to eat salads of roasted vegetables and feta cheese, and, yes, many kinds of avocado toast. But there has also been a colossal rise in the consumption of packaged snack foods and sugary drinks. The balance of what South Africans eat is tipping away from the old vegetables and stews of the rest of sub-Saharan Africa and towards a Westernised diet of fried chicken and burgers and oversized portions of pasta.16
‘These young people have stretched their stomachs,’ observed an old black South African in 2016, startled by the way that children suddenly expected to eat fried foods and meat every day. Middle-income countries such as South Africa have experienced the full fairy tale and the full horror story of food at the same time. Rates of both under-nutrition and over-nutrition in South Africa exceeded 30 per cent of the population as of 2016. In the old days, South Africans ate many wild fruits and breakfasted on a thick maize or sorghum porridge, seasoned to taste with a few drops of vinegar. Now, breakfast is more likely to be nutrient-poor white industrial bread with margarine or jam. With escalating sugar consumption, tooth decay is rising in South Africa at an alarming rate.17
Eating in South Africa, a parched land with relatively poor soil quality, has never been ‘heaven on earth’, as South African dietitian Mpho Tshukudu has written. There is no golden age of food to return to. But nor have South Africans ever had to face food dilemmas quite like the ones they face today on a daily basis. One mother in her forties who came to Tshukudu’s clinic recalled that as a child growing up in a rural village, she walked for miles and ate home-cooked foods every day, always with a vegetable or some kind of legume. She knew no one who was obese and never needed to visit a doctor. But now, this woman lived in the city with her husband and three children and they all ate a lot of takeaway food and were frequently unwell. Her nine-year-old daughter was already so big that, to her distress, she had to buy her clothes in the grown-up section of the store.18
In some ways, South Africa’s new unhealthy pattern of eating is distinctive to the country itself, and to the injustice of the apartheid years. During apartheid, the state controlled who moved to towns and who stayed in the country and no black farmers were allowed to own land outside the ‘homelands’. Adults living in black townships often had long commutes to jobs in the white cities which left less time for cooking than in the past and as a result, some of the old traditional dishes died out.
But the most extreme and sudden changes to South African eating happened after the end of apartheid in the mid-1990s, during and after Nelson Mandela’s presidency, when thousands of black South Africans were lifted out of poverty for the first time. People were free to move to the cities; and they did. By many metrics, life got better and easier, but much of what people were eating now was less healthy than it had been before. As a newly open economy, the country was flooded with fast food and processed food from both home and abroad. From 2005 to 2010, the sales of processed snack bars in South Africa increased by more than 40 per cent.19
New freedom and city living; new snacks and abundance; new obesity and type 2 diabetes: the patterns of both eating and health have shifted fast in South Africa since the 1990s. The speed at which diets are changing here is vertiginous, yet the pattern is a familiar one. It is almost as if South Africa – along with so many other countries in the world – is following a script for eating set by America fifty or so years ago.
Stage four
Growing up in 1950s Wisconsin, Barry Popkin drank only tap water and milk, except for a small glass of orange juice to start the day. His father drank tea and his mother had coffee. At the weekend, as he has explained in his 2009 book The World is Fat, his parents might take a glass of wine for a treat. No one in Popkin’s family drank sweetened lattes or sugary energy drinks and the adults would not have dreamed of drinking alcohol every day. There were no smoothies and no white chocolate mocha frappuccinos. Popkin – Professor of Nutrition at Chapel Hill University, North Carolina – has made it his life’s mission to study the reasons why our patterns of eating and drinking are so different from those of the past; and to figure out ways to save the best of the changes and move beyond the worst of them.20
During the months when I was first researching this book, it felt as if all roads led to Barry Popkin. Whether I was looking for hard facts on snacking or sugar or statistics about how food had changed in China over the past decade, Popkin always seemed to have co-authored the definitive paper on the subject. He was also involved in working with governments to create better food policies in many countries including Mexico, Chile, Colombia and Brazil. His website showed a photo of a cheery-looking man in his seventies with a white beard, but this Popkin was so prolific, I was starting to doubt whether he really existed, or whether he was in fact a team of nutrition academics working out of a factory somewhere.
When I contacted Popkin to arrange a telephone interview, he emailed straight back and told me he was having a ‘horrendous’ week but could take my call at 9 a.m. EST precisely on Monday morning. A gruff-voiced man answered the phone and immediately started explaining how food had radically changed in recent years, not just for a few people but for billions across the world. He spoke with great authority about the marketing of crisps and convenience foods; about the rise of highly sweetened drinks and the fall of home cooking. ‘It’s a radical change,’ Popkin told me, ‘and it’s going to be a big battle to reverse it.’
Popkin’s interest in nutrition started, he has written, during a year in India in 1965–6 when he was an economics student living in shantytowns in Old Delhi. India was a shock because after his modest but comfortable American childhood, Popkin was exposed to the extremes of hunger first hand. Returning to the States determined to use economics to help improve the way people ate, he assumed that the great problem to be solved with respect to nutrition would always be hunger.21
By the 1980s, however, Popkin had noticed that obesity had begun to replace hunger as the main nutritional problem in the Western world and he observed, aghast, as the same set of chronic diseases swept across the globe. He was one of the first experts in the field to argue that obesity was a global problem, not a phenomenon of the West. Popkin coined the phrase ‘nutrition transition’ to explain the changes he saw happening around the world as countries developed from poverty to riches. As a country becomes richer and more open to global markets, its population almost inexorably starts to eat differently, consuming more oil and meat and sugar and snack foods and fewer wholegrains and pulses. Wherever this diet was adopted, Popkin noticed, it brought with it easier lives as well as a host of diseases.22
One way to think about human history is as a series of diet transitions, with each stage driven by changes in the economy and society, plus shifts in technology, climate and population. In the beginning, we were hunter-gatherers, eating a mostly low-fat diet of varied wild greens, berries and wild animals. During the Upper Paleolithic Period, which began about fifty thousand years ago, more than half of our food came from plants and the rest came from animals. In these societies, people were forced to collaborate to collect food. We had discovered fire but not cooking pots. Life expectancy was low – you were at risk of dying a violent death, if infectious diseases didn’t get you first. But the archaeological record suggests that (depending on where in the world they lived) the humans in this phase who survived into adulthood experienced mostly good health, with few nutritional deficiencies.
Stage two, starting around 20,000 BCE, was the agricultural age, which was characterised by a switch to staple cereals and a huge increase in population. Now we had clay cooking vessels and more sophisticated grindstones at our disposal. The hunter-gatherer diet of wild plants and meats gave way to diets based on staple cereals, whether it was the rice and millet of China or the barley of Mesopotamia. Farming bestowed huge benefits. It created food surpluses for the first time, which freed many people from the task of food gathering and gave rise to vast new civilisations such as that of the Indus Valley, where modern-day Pakistan lies. Grains were a very efficient way to generate calories from the land. Without agriculture there would have been no cities, no politics, no human civilisation as we know it.
The downside of farming, however, was that it gave people a less varied range of foods than before. Along with the adoption of staple cereals, phase two saw a rise of famine and a sudden increase in diet-related problems. With diets that were often inadequate both in quantity and quality, humans shrank in stature and suffered from a range of deficiency diseases. The difference in human health between the diets of stage one and stage two is the rationale behind the popular ‘Paleo diet’ in which modern dieters try to turn the clock back by ten thousand years or so and eat as if farming had never been invented.
Then again, to find a diet healthier than the one most people eat today, we don’t need to go back thousands of years. In Europe, we could go back a mere couple of hundred years to the third stage, which Popkin calls ‘receding famine’. During this period, advances in agriculture such as crop rotation and fertiliser led to a more varied and plentiful diet, with fewer starch-based staples and a bigger variety of vegetables along with animal protein. In stage three, the possibilities of cooking expanded, with new methods of drying and preserving and pickling. This period also witnessed a slow decline in mortality. Many of the old deficiency diseases – such as scurvy and beri beri – became less common as diets became more nourishing. On Popkin’s model, many sub-Saharan African countries are living through this stage now. This would explain why their diets compare so favourably, in Imamura’s paper, with those of the industrialised world.
But then comes stage four, which is where we are now. This era is different in quality from any of the other stages. Suddenly, the diet changes much more rapidly, with consequences for human health which are more extreme. The economy shifts away from manual labour and towards mechanisation, people move from the countryside to cities and they start to expend less energy. There are revolutions in food processing and marketing and people start to eat more fat, more meat and more sugar, with far less fibre. Stage four sees human life expectancy hit new highs with the decline of deficiency diseases and the breakthroughs of modern medicine. But it also sees populations suffering from diet-related chronic illness as never before. The ‘nutrition transition’ happened all over the Western world in the decades after the Second World War and is now happening even faster among low- and middle-income nations in the rest of the world. This transition explains why our food is sickening us now, through excess rather than hunger.
Stage four is a radical break with the past which represents a reinvention of food and what it means for human life. One of the greatest departures of stage four is the new homogeneity of food. As agriculture becomes a vast international form of trade, people start relying on the same small number of global crops, even when they live oceans and continents apart.
For centuries, eaters have marked high days and holidays with moreish fried foods such as fritters and doughnuts. Only in modern times, however, could a person buy a stackable carton of fried crisps made from a slurry of dried potatoes and wheat starch seasoned with barbecue flavouring and sit on a sofa eating them not for a celebration, not even out of hunger, but just out of a mild feeling of restless boredom. Only in stage four could another person – in the same mildly bored state – be eating exactly the same crisps at the exact same moment on another sofa somewhere halfway across the world.
The Global Standard Diet
The nutrition transition has not just taken place at the level of supply. It has also altered our personal hungers so that we become people who gravitate towards the same foods. Between the 1960s and today, people around the world stopped depending so much on their own particular foodstuffs, the ones that belonged to our own families and homeland, and started eating other, alien commodities, grown in faraway places. Soon, we were eating so many of these alien foods that they stopped tasting strange to us and starting tasting normal. We changed not only the dishes we ate but the basic composition of our diets.
Nations have adjusted their food habits many times before – after all, tomatoes are not native to Italy, nor tea to Britain – but the recent global homogenisation of taste is unprecedented. All at once, billions of eaters in disparate places have started eating from the same repertoire of ingredients. Never before has such dietary change happened on such a scale, and simultaneously across most of the planet. It is a switch so pervasive and so huge that we haven’t had time to react or even to notice exactly what has changed. It is as if the colour of the sky morphed from blue to green, but before we could protest that something was not right, our eyes adjusted and we carried on as normal.
In the past, it was a fundamental fact about human beings – and about food – that people ate different things in different places. It’s in our nature as omnivores to be skilled at adapting to varied food environments. If you ask someone ‘what’s food?’ you would expect to receive wildly different answers to the question whether you were in Lagos or in Paris. In the past ‘food’ was not one thing but many, varying according to local crops, local ingredients and local ideas and prejudices.
When I was a child in the 1980s, I remember grown-ups in Britain talking with horror about the fact that the Japanese liked to eat … raw fish! It seemed so improbable. From their tone of baffled revulsion, these Britons might as well have been contemplating swallowing live frogs. I never imagined that one day those same grown-ups, older and greyer, would stroll into a perfectly normal shop on the average British high street and casually pick up a tray of sushi for lunch. We now live in a clone-world where you can get pizza in Beijing and Chinese dumplings in Rome, and not even be startled by the incongruity.