Many people who lives a long life have low insulin within the normal range. And sugar spikes insulin and should be avoided. Most cenenarian do eat meat.
Robb Wolf says that …
“centenarians ALL eat red meat, typically drink a little, are go-getters in attitude.”[reference]
And in his podcast 146, he says …
“one of the things that we see as a defining element of people living longer is that
they tend to eat more protein.”
Paul Jaminet found that centenarians tend to eat two types of diets:
1) Calorie-restriction and intermittent fasting.
2) High (saturated and monounsaturated) fat low-carb diets.
Of course there are some with good genes that can eat anything and still be healthy. Look at George Burns who smokes and lives to 100.
Typical Lifetime Dietary Habits of Centenarians