Ravenous: How to get ourselves and our planet into shape

by Henry Dimbleby

The bigger the market, the greater the economies of scale. Highly processed foods – high in salt, refined carbohydrates, sugar and fats, and low in fibre – are on average three times cheaper per calorie than healthier foods. This is one reason why bad diet is a particularly acute problem among the poorest.

In 1950, less than 1 percent of the UK population was clinically obese. Today, that figure stands at 28 percent. Are we to believe that, in the intervening years, the British public has suffered a massive collapse of willpower? Of course not. People haven’t changed; the food system has.

Globally, we now produce around 50 percent more calories than we need per head. (Much more than that if you include all the crops that get fed to livestock.)

The underlying belief here is that we are getting fat and ill because we are too lazy to take exercise, and too ignorant to eat well. If only we were better informed about healthy eating, and more conscientious about getting up off our enormous bottoms, the obesity crisis would melt away.

In fact, the true model is the one below: the Constrained Total Energy Expenditure Model. When we increase our physical activity, the body fights back by reducing the energy it spends on the resting metabolism. This is why it is so hard to lose weight through exercise alone.

across the board, people in less developed, more physically active populations have the same daily calorie expenditures as their more sedentary counterparts in rich countries.

Once we began to develop large, energy-hungry brains, we learnt how to find and cook food from many different sources. Cooking our food helped reduce the amount of energy required for digestion, freeing up more energy for our growing brains. A reinforcing feedback loop.

The biological imperative is to stay healthy long enough to mate. Live fast, pass on your genes, die in a hunting accident.

Pontzer suggests this might explain why diseases of the immune and reproductive systems, such as breast cancer, Crohn’s disease and IBS, have become so common in developed societies. We move so little that to maintain our total energy expenditure, our bodies invest too much energy into the systems governed by our resting metabolism. This leads to chronic inflammation, stress and reproductive cancers in industrialised populations.

What is clear, from study after study, is that exercise is not a good way to lose weight. If you increase your exercise level, your body will gradually adapt to moderate your energy output.

Exercise benefits everyone, regardless of weight. If it could be prescribed it would be one of our most powerful and multi-disciplinary drugs. But in the public imagination it is associated almost exclusively with weight loss. And because it doesn’t work well for that purpose, people get disillusioned and give up. The amazing things that exercise can do are eclipsed by the one thing it can’t.

Crash diets, in all their forms, make us ravenous – and not just in the weight loss phase. They increase our ghrelin levels even after we have started eating normally again. For months afterwards, ghrelin levels remain high, making us hungrier than we were before we tried to lose weight.

the British eat more ultra-processed food than any other European country. It comprises 57 percent of our diet, according to the British Medical Journal. This compares to 46 percent for Germany, 14 percent for France and 13 percent for Italy. So what is this ultra-processed diet doing to our bodies?

The average person, globally, eats 35 tonnes of food over a lifetime. Americans eat more than twice that amount – and we Brits are not far behind. This torrent of food doesn’t just pass through us; it becomes us. It is used to make new cells, blood and tissue and bone.

In modern Britain, the way we eat is one of the clearest markers of inequality. You can actually see it with the naked eye. A diet of cheap junk food has the peculiar quality that it can make you simultaneously overweight and undernourished.

In these so-called ‘food swamps’, it can be impossible to find non-processed food. Roughly 3.3 million people in the UK live in areas where there are no shops selling fresh ingredients within 15 minutes by public transport.

Cooking requires technology, even at the most basic level. There are currently 1.9 million people in the UK living without a cooker, 2.8 million people without a freezer and 900,000 people without a fridge. Many more households have the relevant white goods in place, but not enough money to run them.

Since 1992, UK governments have tried 689 different anti-obesity schemes, with no success. That is because these schemes are almost all concerned with individual responsibility – trying to help people resist the temptations of an obesogenic environment* – rather than changing the environment itself.

The OECD estimates that the combined cost of food-related disease, in lost workforce productivity, low educational outcomes and NHS funds, is £74 billion every year in the UK. This is equivalent to cutting the country’s GDP by 3.4 percent.

We simply cannot reduce greenhouse gas emissions to a safe level without cutting back on meat consumption.

It is awful to contemplate the misery we inflict on animals before we eat them – which is why, on the whole, we prefer not to think about it. Ironically, this squeamishness is itself a by-product of the food system. If we hadn’t learnt to cook and eat other species, we would never have developed our big, complex brains. And without those brains we would not be able to comprehend the moral consequences of what we have done. But neither would we have the intellectual muscle required to put right our mistakes.

Over a quarter of all the food grown in the UK never makes it into our bellies. This accounts for 6–7 percent of total UK greenhouse gas emissions. Globally, the figures are even more eye-popping: 28 percent of the world’s agricultural land is used to grow food that is never eaten.

When farmers are planting their crops, they have to allow for more than enough to satisfy our expected appetites. Otherwise, if disease or bad weather ends up reducing their yield, they might be unable to fulfil their supermarket orders. Overproduction is therefore built into the system.

This is not a summons for everyone to go vegan. Just cutting back is enough. If everyone in the UK reduced their intake of meat and dairy by one third, that would free up around 20 percent of our farmland. This might be a lifestyle change for many, but it can hardly be described as a privation. If you usually eat meat and dairy at every meal, why not try going without on Mondays and Tuesdays? Job done.