Diet fads come and go, like New Year’s resolutions, and often have little impact on our waistlines.

But a cohort of scientists has developed one with the potential to improve not only our health, but the health of planet Earth too.

Image: EAT-Lancet

The ‘planetary health diet’, which involves a shift towards plant-based eating, was designed by 37 experts as part of the EAT-Lancet Commission to answer the question of how we’re going to feed a projected 10 billion people, without destroying the planet, by 2050.

The report says: “This includes a more than doubling in the consumption of healthy foods such as fruits, vegetables, legumes and nuts, and a greater than 50% reduction in global consumption of less healthy foods such as added sugars and red meat.”

It found the “major health benefits” (Target 1) of moving to a healthy diet would include preventing around 11 million deaths a year. That is equivalent to 19 to 24% of total adult deaths.

The EAT-Lancet Commission’s second target is to reduce the environmental impacts from food production through a combination of “a global shift toward healthy diets, improved food production practices and reduced food loss and waste”.

Image: EAT-Lancet

So what can we eat?

Almost every country will need to make some adjustments to their meals to adopt the diet, and the commission will take its findings to global bodies and governments to encourage just that.

Crucially, the commission is recommending a shift towards ‘flexitarianism’ rather than veganism, saying: “Many populations continue to face significant burdens of undernutrition and obtaining adequate quantities of micronutrients from plant source foods alone can be difficult.

“Given these considerations, the role of animal source foods in people’s diets must be carefully considered in each context and within local and regional realities.”

As the below chart shows, the main change to many Western diets is going to be in the consumption of red meat, cutting back to only 14g a day (and just 30 calories), which equates to about a mouthful of a typical Sirloin steak.

Starchy vegetables, including potatoes and cassava, a staple in African countries, are limited to just 50g a day, while fish, which is such a big part of Japanese and other East Asian diets, is limited to 28g.

Image: EAT-Lancet

Instead of red meat, protein should come from eating more legumes (75g a day), such as chickpeas and lentils.

Vegetables should make up the biggest portion of our meals (300g per day), with saturated fats, such as oils, making up the lowest portion (just 11.8g).

The majority of our daily calorie intake will come from whole grains (232g, 811 kcal), while added sugars should only give us 120 calories a day, with a maximum intake of 31g - or about eight teaspoons of sugar.

Commenting on the diet, David Yeung, co-founder and CEO of plant-based social movement Green Monday and one of the World Economic Forum’s Social Entrepreneurs of 2018, told the World Economic Forum the diet would be achievable if people started with small steps: “Everyone can become a flexitarian by choosing to simply reduce meat and go green one day, two days or five days at their convenience.”

The global food problem

The report comes two weeks after the World Economic Forum published its white paper on Alternative Proteins, as part of its Meat: the Future dialogue series, which found that balancing meat consumption with alternative sources of protein can provide multiple benefits across health and the environment.

Lisa Sweet, Head, Business Strategy and Engagement at the World Economic Forum, said: “Transformation of the food system and consumption patterns to deliver healthy and sustainable protein to a growing population will require action along three pathways: scaling alternative proteins, improving how we currently produce meat, and incentivizing and enabling consumer behaviour change.

“For dietary transformation to take place, partnerships and multi-stakeholder efforts will be essential to shape common narratives that originate from a scientific evidence base and are framed in ways that resonate with peoples’ aspirations to encourage the adoption of alternatives.”

Sean de Cleene, the Forum's Head of Future of Food, added: "Sustainably nourishing 9.8 billion people by 2050 presents an immediate challenge for the global food system. This will require a step change in innovation and an unprecedented degree of cooperation, to evolve production, value chains, market systems, technology and the nature of consumer demand - transcending from the local to the global."

Healthy diets are critical, with 2.8 million a year globally dying from being overweight or obese, according to the World Health Organization.

The EAT-Lancet report says: “Unhealthy diets now pose a greater risk to morbidity and mortality than unsafe sex, alcohol, drug and tobacco use combined.”

The global population currently stands at 7.7 billion and the UN expects that figure to rise to 9.8 billion in 2050, which means more mouths to feed - with more water required in food production, as well as more damaging greenhouse gases emitted.

In short, it’s unsustainable for the world to keep up with our current demand for certain foods.

The EAT-Lancet report measures the ‘diet gap’ between current dietary patterns and intakes of food in the planetary health diet. Globally, for red meat, this gap is 288%, while in North America, it rises to 638%. For starchy vegetables in sub-Saharan Africa, the gap is 729%.

Image: World Bank

According to the UN’s Food and Agriculture Organization, emissions from global livestock account for 14.5% of anthropogenic (from human activity) greenhouse gases, while the World Bank chart above shows that, in 2014, 70% of freshwater withdrawal was used for agriculture - projected to rise by a further 15% by 2050.

To address these issues and help the world meet the Paris Agreement target of keeping global warming to below 2°C by 2050, the EAT-Lancet Commission proposes 5 “strategies for a great food transformation”, as follows:

  • 1. Seek international and national commitment to shift toward healthy diets
  • 2. Reorient agricultural priorities from producing high quantities of food to producing healthy food
  • 3. Sustainably intensify food production to increase high-quality output
  • 4. Strong and coordinated governance of land and oceans
  • 5. At least halve food losses and waste, in line with the UN Sustainable Development Goals

As the Commission concludes, in order to “safeguard the natural systems and processes that humanity depends on”, there must be greater cooperation between all sectors to implement a “Great Food Transformation”.