The Way We Eat Now. Би УилсонЧитать онлайн книгу.
look the way we expect it to.
Despite the decline in hunger, malnutrition in all its forms now affects one in three people on the planet. Plenty of countries – including China, Mexico, India, Egypt and South Africa – are suffering simultaneously from over-feeding and under-nutrition, with many people suffering from a surfeit of calories but a dearth of the crucial micronutrients and protein a body needs to stay healthy. As a result, not just in the West but across the world, people are suffering in growing numbers from diseases such as hypertension and stroke, type 2 diabetes and preventable forms of cancer. The lead cause of these diseases is what nutritionists call ‘suboptimal diet’ and what to the rest of us is simply ‘food’.7
Our ancestors could not rely on there being enough food. Our own food fails us in different ways. We have markets heaving with bounty but too often, what is sold as ‘food’ fails in its basic task, which is to nourish us.
To walk into the average supermarket today is to be greeted not just by fresh whole ingredients, but by aisle upon aisle of salty oily snacks and frosted cereals, of ‘bread’ that has been neither proved nor fermented, of sweetened drinks of many hues and supposedly ‘healthy’ yoghurts that are more sugar than yoghurt. These huge changes to modern diets have gone hand in hand with other vast social transformations such as the spread of cars, electric food mixers and electronic screens of many kinds, which have left us far less active than earlier generations, gym membership or not. The mechanisation of farm work which created the food to feed billions also resulted in farmers (in common with most of the rest of us) leading increasingly sedentary lives.
In just a few decades, these alterations to how we eat have left unmistakable marks on human health. Take type 2 diabetes. The causes of this chronic condition, whose symptoms include fatigue, headaches and increased hunger and thirst, are still being debated by scientists, but there is clear evidence that – genetics aside – there is a higher risk of getting type 2 diabetes if you habitually consume a diet high in sugary drinks, refined carbohydrates and processed meats and low in wholegrains, vegetables and nuts.
In 2016, more than six hundred children in the UK were registered as living with type 2 diabetes. Yet as recently as 2000, not a single child in the country suffered from the condition.8
So are we living in a food paradise or a food hell? It doesn’t seem possible to reconcile these competing stories about modern food. But in 2015, a group of scientists in the United States, the UK and Europe devised a systematic assessment of the world’s diet which showed that both stories are true: the world’s diet is getting better and worse at the same time.
Where the balance falls
The light is fading on a cold winter’s day. I am sitting in a café at the top of the Cambridge University graduate students’ union with Fumiaki Imamura, a 38-year-old scientist. He drinks black coffee; I drink English Breakfast tea. Imamura, who has a Beatles haircut and a bright purple tie, is originally from Tokyo but has spent the past fifteen years in the West, studying the links between diet and health. ‘There are so many myths about food,’ Imamura says. One of the myths he refers to is the notion that there is such a thing as a perfectly healthy diet.
Every single human community across the globe eats a mixture of the ‘healthy’ and the ‘unhealthy’, but the salient question is where the balance falls. Imamura’s research shows that most countries in the world are currently eating more healthy food than we ever did; but also more unhealthy food. Many of us have a split personality when it comes to food, but then this is hardly surprising given how schizophrenic our food supply has become. We have access to more fresh fruit nowadays than we ever did; plus more sugar-sweetened cereals and French fries.
Imamura is a nutritional epidemiologist, meaning that he studies outlines of diet across whole populations to arrive at a more accurate account of how food and health are related. He works in the MRC Epidemiology Unit on the Cambridge Biomedical Campus. Imamura is one player in a much larger research team which straddles multiple universities in the United States and Europe. The overall project is based at Tufts University in Boston and is led by Professor Dariush Mozaffarian, one of the leading scholars currently using big data to measure nutrition in countries worldwide.
In 2015, Imamura was the lead author on a paper in medical journal The Lancet which caused a stir in the world of nutrition science. This team of epidemiologists have been seeking to map the healthiness, or otherwise, of how people eat across the entire world, and how this changed in the twenty years between 1990 and 2010.9
At this point, you might ask, what counts as a good quality diet? Some would define healthy food in positive terms: how many vegetables and portions of oily fish a person eats. Others define it more negatively, judging it by an absence of sugary drinks and junk food. Clearly, these are two very different ways of looking at the question. Most research on diet and health has lumped the two together, assuming that a high intake of ‘healthy’ fish will automatically go along with a low intake of ‘unhealthy’ salt, for example. But, alas, human beings are inconsistent creatures.
The Japanese, who are generally considered to eat an outstandingly ‘healthy’ diet as rich nations go, consume large amounts of both fish and salt: the one ‘healthy’ and the other ‘unhealthy’. They consume much refined polished white rice (‘unhealthy’) along with copious amounts of dark green vegetables (‘healthy’). Imamura himself still eats a diet centred on vegetables and fish, he tells me, but also a lot of salt in the form of soy sauce, even though as an epidemiologist he is aware that high sodium intake has been linked in numerous studies to high blood pressure. But he is conscious that no population in the world eats exactly the combination of healthy foods that nutritionists might recommend.
There have been many attempts to measure the healthiness of the world’s diet in the past but most studies have treated human eaters as more rational than we actually are. Previous studies have summed together high consumption of healthy foods and low consumption of unhealthy foods. What made Imamura’s paper so innovative – and so much closer to the way we actually behave around food – was that he and his fellow researchers studied healthy and unhealthy foods in two parallel datasets.
Imamura and his colleagues came up with a list of ten ‘healthy’ items: fruits, vegetables, fish, beans and legumes, nuts and seeds, wholegrains, milk, total polyunsaturated fatty acids (the kind of fat found in seed oils such as sunflower), plant omega 3s and dietary fibre. They created a separate list of ‘unhealthy’ items: sugary beverages, unprocessed red meats, processed meats, saturated fat, trans fat, cholesterol and sodium. (Imamura knows that some would quibble with the items on these lists. There is an ongoing debate among nutrition scientists about the healthiness or otherwise of saturated fats versus unsaturated fats. It looks as though the key question with saturated fat, as with other nutrients, is not whether it is unhealthy in absolute terms, but what you choose to eat instead of it. There is evidence that replacing saturated fats with processed carbohydrates can be harmful for heart health, whereas replacing it with olive oil or walnuts may have benefits.10 But based on everything that the epidemiologists currently knew about patterns of diet and health outcomes, these lists were the best they could do.) The researchers then tried to map a pattern of how much of these healthy and unhealthy foods are eaten in any given country.
‘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