@charitybot yup you are right. Even the most studied long-lived population in Japan (probably in the whole world) called the Okinawan people has been consuming a high carbohydrate diet and they get to live up to 100 years old. It really depends on the kind of foods you were taking (Okinawan people eat mostly organic food). The Ketogenic diet is quite strict and most of the food items which are recommended to be taken when you are in this kind of diet were expensive. As eating is one of the components which could determine longevity, it's quite a bit of a headache to decide, what kind of food you want to eat later in order to stay healthy, say, 10 years in the future.