We are what we eat. That is an old expression, but one worth knowing. A recent look at diets around the world shows that people who eat healthy food -- and not too much of it -- live longer. But which areas of the world have the best diets? The Lancet Global Health medical journal has published findings on whose diets are the best. Researchers studied the dietary quality of people in 187 countries from 1990 to 2010. The Bill & Melinda Gates Foundation and Medical Research Council supported this study. It found that foods found in some of the healthiest diets -- Mediterranean, New Nordic, French and Japanese -- may be very different, but they do have things in common. They are all heavy on local, seasonal foods and limit processed foods. They are high in vegetables and seafood and low in red meat.