A longevity expert has named the superfood that is a 'cornerstone of every blue zones diet.' Dan Buettner is a National Geographic Fellow who has spent decades studying 'blue zones', the geographic areas with the world’s highest proportions of centenarians. He is also a New York Times bestselling author.

As part of his work, Buettner regularly answers questions about his own diet and the lifestyle changes he has incorporated into his daily routine based on his research. Speaking to Meat Free Mondays, a not-for-profit campaign launched by Paul, Mary and Stella McCartney, the author explained why he chooses to eat meat-free.

He said: "I’ve spent over 20 years studying the diets of the world’s longest-lived people in the blue zones. What I’ve seen consistently is that people who live the longest and healthiest lives eat mostly whole, plant-based foods with very little or no meat."

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Buettner also recommended a superfood that he eats. When asked to name the items always kept in his fridge, the author answered: "You’ll almost always find beans – black beans, lentils, or chickpeas – because they’re the cornerstone of every blue zones diet."

He added: "I keep a variety of fresh vegetables, leafy greens and herbs so I can throw together quick meals. There’s usually sourdough bread, some nuts and seeds, and a good bottle of olive oil too."

Beans have long been a popular component in meals for people seeking a healthy meal that will keep them feeling fuller for longer. As the NHS explains, beans are a good source of fibre and protein.

With a mix of vitamins, nutrients, and minerals, beans count as one of your recommended Five A Day. If you opt for green beans, such as runner beans or broad beans, which count as vegetables, you could include them as another portion of your Five A Day.

Nonprofit, multispecialty academic medical centre, Cleveland Clinic, goes so far as to call beans 'nutritional powerhouses' and a 'superfood'. The medical centre explains: "Eating beans can help lower cholesterol, maintain healthy blood sugar levels, fight cancer, promote digestive health and even help manage weight."

People who want to eat more beans could incorporate them into their diet by adding beans to salads, soups, stews, and chilis, or blending them into dips. They can also be used to replace meat in tacos or to replace flour in baked goods. However, it's recommended to start with small portions and gradually increase them to reduce gas.

The NHS emphasises that a healthy diet is balanced. It's important to eat a variety of foods and consume them in the right proportions. The Eatwell Guide says people should try to:

• eat at least five portions of a variety of fruit and vegetables every day


• base meals on higher fibre starchy foods


• have some dairy or dairy alternatives


• eat some beans, pulses, fish, eggs, meat and other protein


• choose unsaturated oils and spreads, and eat them in small amounts


• drink plenty of fluids