Many blue zone diets are rich in plant foods. Studio Romantic/ Shutterstock January 24, 2024 People in the world’s ‘blue zones’ live longer – their diet could hold the key to why Justin Roberts, Anglia Ruskin University; Joseph Lillis, Anglia Ruskin University, and Mark Cortnage, Anglia Ruskin University Centenarians living in the world’s ‘blue zones’ share a surprising number of similarities when it comes to their usual diet.