By Jennifer Cole, Royal Holloway, University of London
It has long been clear that certain foods and dietary choices are not good for human health, but there is now increasing evidence that they can also be bad for the health of the planet. The recently published Food in the Anthropocene: EAT-Lancet Commission on healthy diets from sustainable food systems highlights that it may not be possible to feed a future population of 10 billion people a healthy diet within planetary boundaries unless we make significant changes to our diets and to the way food systems are managed. In particular, we need to eat much less meat, particularly red meat from grain-fed livestock.
Reducing the amount of red meat in the diets of developed countries’ urban populations, and ensuring that the amount eaten by the populations of emerging economies such as China and India, never reaches these levels, is essential for protecting the Earth from land clearance, greenhouse gas emissions, biodiversity loss and antimicrobial resistance. It will also protect Earth’s inhabitants from an equally wide range of harms including obesity, heart diseases, cancers and diabetes – not to mention preserving antibiotics efficacy against future infections.
So why is (red) meat so bad for us and for the planet? One answer could be that it’s not – in moderation. But humans have never been very good at doing things in moderation, a hangover from our evolutionary development when food was scarce, and we had to grab what we could. In the distant past, our craving for fat and sugar served us well when we were foraging for what we could find. It encouraged us to grab calorie-dense foods on the rare occasions we encountered it. This serves us less well when we can produce as much food, of whatever type we like best, however: we just eat too much of the wrong thing. Our evolutionary programming has fallen out of pace with the environments we now inhabit – a theory known as adaptive lag hypothesis – with serious consequences for our health. Very few of us still live a hunter-gatherer existence in which (unprocessed) meat is a rare treat, but our genetic programming hasn’t noticed that yet and our bodies are paying the price: worldwide obesity has nearly tripled since 1975, 36% of the world’s adults were overweight in 2016, and more than 40 million children under five were overweight or obese. Red meat and other animal derived proteins and fats are risk factors for many non-communicable conditions including heart disease, cancer and obesity.
Just as red meat and animal fat is bad for our bodies, it’s also bad for the Earth (and not great for the food animals, either). Livestock occupy 77% of Earth’s finite supply of agricultural land and are the leading cause of land conversion and biodiversity loss. Livestock use land less efficiently than crops: to produce 1g of beef protein requires more than 1m2 land, whereas creating the equivalent weight of protein from pulses requires 100 times less. Livestock consume over half of the world’s grains, which could be instead consumed by people. As the Earth’s population grows, and we are forced to increasingly grow more food, more efficiently on the agricultural land available, we need to turn to more efficient and less damaging plants as our primary sources of protein.
It’s not only for the sake of land that we need to reduce dietary reliance on livestock: the atmosphere is also suffering. Food animals – particularly ruminants such as cows, sheep and goats – are responsible for 18% of all anthropogenic greenhouse gas emissions and 67% of all emissions from food. Livestock also consume 70-80% of the world’s antibiotics: in a business-as-usual scenario, livestock antimicrobial consumption is predicted to increase from 131,000 tonnes in 2013 to more than 200,000 tonnes in 2030, risking a significant rise in antibiotic resistance that will lead to infectious disease in humans (and animals) being much more difficult to treat.
These multifaceted concerns around improving our diets for the sake of our health and to protect the planet at the same time, is leading to rising interest in vegetarianism and veganism in many countries, with many people actively reducing the amount of animal products they eat. Even if going the whole way towards eliminating meat from the diet seems a step too far, the EAT-Lancet commission recommends that if we can’t cut out meat, we should at the very least cut it down: in the typical Western diet, by as much as 90%. Our bodies only require an average of 40-50g of protein a day – the equivalent of a small burger, and this can be provided from plant proteins such as beans, nuts and pulses, which are less likely to contain dangerously high levels of fat. The EAT-Lancet Commission suggests consuming only around 100g of red meat, 200g of white meat and 200g of fish per week. And if you want to cut meat out of your diet completely, there is no reason not to: virtually all macro and micronutrients we need can be obtained from plant sources. Recent research into alternatives to animal protein are even identifying adequate plant sources of micronutrients such as B12, previously a concern in vegan diets, including coconut milk, rice milk and almond milk as well as in fermented tofu, soya, and a variety of yeast extracts.
The EAT-Lancet commission describes a diet that favours increasing the consumption of a variety of fruits, vegetables, nuts and legumes alongside small portions of meat and dairy as a “planetary health diet” that could prevent 11 million premature adult deaths per year and drive the transition towards a sustainable global food system that, by 2050, will ensure healthy food for all within planetary boundaries. Taking a more holistic approach to our food, the food systems that supply it, and the agricultural practices behind it will help us manage healthy and sustainable diets far into the future, not only meeting the targets of the Sustainable Development Goals on eradicating world hunger, but also protecting the health of all populations from a range of communicable and non-communicable diseases into the bargain.
Planetary Health: Human Health in an Era of Global Environmental Change, edited by Jennifer Cole, will be published by CABI in July 2019
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