The idea of eating lots of plants fits with what we know about the microbiome, and indeed some recent research suggests that the very reason the Mediterranean diet is so good for us is the way it influences our gut microbes.22 People in Okinawa also tend to eat very few calories, even by Japanese standards, a hint that keeping calories low, as we learned in the previous chapter, could be a good strategy for health. The diets of blue-zoners also fits with the recent finding that a poor diet is the leading cause of death in most countries. The biggest culprits? Too much salt, too few whole grains and not enough vegetables. Exactly the opposite of the blue-zone diet.
Med diet marvel
Living longer is one thing, but what about the brain? Here, the Mediterranean diet really comes into its own. Studies consistently find that sticking to it reduces the risk for numerous brain conditions including stroke, depression and Alzheimer’s.23 On the other hand, unhealthy diets high in processed foods have been linked to increased risk of depression as well as anxiety.24 Diet and mental health, then, are clearly connected, but most of these studies are observational – meaning that people’s habits are observed and measurements are made, but the scientists aren’t trying to change the outcome – so we can’t definitively say that diet is the driving force.