The one diet that’s good for everything: Best ideas of the century

The Mediterranean diet is the crème de la crème of healthy eating. Filled with fibre, vegetables, legumes, fruit, nuts, some fish and minimal meat and dairy, it brings a smorgasbord of health – and planetary – benefits, all while being utterly delicious. “It’s not only healthy, it’s also extremely tasty,” says Luigi Fontana at the University of Sydney in Australia.

Unlike certain dietary fads, the Mediterranean diet is backed up by decades of evidence. But it is only in the 21^st century that a series of randomised controlled trials established it as the scientific gold standard.

In the 1940s, physiologist Ancel Keys was among the first to argue that the diet cuts the risk of heart disease thanks to low levels of saturated fat – found in meat and dairy – which increases the presence of artery-clogging cholesterol.

Keys and his wife Margaret, a nutritionist, conducted a study comparing people’s diet and heart health across seven countries, discovering that the Mediterranean diet was linked to a lower risk of heart disease. But they didn’t account for other factors, such as participants’ income levels, that may have influenced the association.

Stronger evidence came in 1999 when scientists randomly assigned people who had previously had a heart attack to follow either a Mediterranean diet or a low-fat one. This demonstrated that the Mediterranean diet really does seem to reduce the risk of stroke and heart attack.

The finding paved the way for a revolution in our understanding of the diet over the next 25 years. After 2000, several randomised controlled trials confirmed the cardiovascular benefits. They also revealed that the Mediterranean diet cuts the risk of type 2 diabetes. That’s not all: subsequent studies have linked it to a reduced risk of breast cancer, slower cognitive decline and a greater chance of successful in-vitro fertilisation, although more evidence is needed to confirm all this. “By eating a Mediterranean diet, you decrease your risk of developing multiple chronic diseases,” says Fontana.

We are also gaining insights into why the diet is so good for us: fibre and extra virgin olive oil seem to be crucial. Both are thought to boost “good” gut bacteria that reduce harmful inflammation. “A lot of chronic diseases are driven by inflammation, so that’s one reason why eating [the] Mediterranean diet is so beneficial,” says Richard Hoffman at the University of Hertfordshire, UK.

Eating this diet also helps the environment, because producing meat and dairy accounts for about 15 per cent of global greenhouse gas emissions, while legumes and vegetables have a much lower impact. As the world heats up, we need to brush away the fads and embrace the diet that has been there all along.