You won't find any centenarians that eat vegan. India is one of the countries with the highest diabetes numbers and vegan. Japan, on the other hand, has the most centenarian and they eat basically unprocessed food and low carb.
Their diet is generally not that good though - tons of carbs, little physical activity unless in 'blue collar' job. Older folks are almost always overweight. Maybe genes also don't help, not sure there.
Studies of their diets indicate that almost all of them are primarily vegetarian and they receive the majority of their calories from carbs. Feel free to look into them. Note that the blue zone in Sardenia is a big outlier even within the group.