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.
