"Science now tells us that not only are we able to protect our brains from the aging process, but we can continue to grow new brain cells throughout our lives," James Goodwin, a professor of physiology, told The Telegaph. at Loughborough University.

In his book Supercharge Your Brain, he explains that the brain is the most vital organ in the body, but unfortunately few of us know how to keep it healthy. He suggests several ways we can improve brain health, including the hara hachi bu practice .

"Excess overload fills the brain with free radicals," said Prof. Goodwin for the Telegraph. "There are five areas of the world where people live longer and have the sharpest minds and what they have in common is that they do not eat much."

One of these places is Okinawa, a remote Japanese island, where a popular mantra is hara hachi bu, which translates as "Eat until you are 80% full".

He said he never eats after 8pm and before 10am, so he does intermittent fasting for 14 hours.

In terms of location in Japan, Okinawa is home to some of the world’s oldest women, who eat soy-based foods and practice tai chi, a form of meditation exercise. This area is known as the Blue Zone, where the longest living people in the world live (click here ).

Other healthy habits for the brain are: physical activity, talking to people, regular sexual activity and learning a new skill.