Afaik, the best diets for longevity are based on calorie reduction. For some reason that doesn't compromise the immune system, and a stronger immune sys leads to a layer death.
Exactly, and to that point, many many "diseases" can be cured with a prolonged water fast (10-40 days, depending on severity, and obviously closely monitoring vitals throughout the process). It's incredibly unfortunate that not more people have access to this very simple guidance. Diabetes (yes, some type 1s included), Crohn's, Colitis, arthritis, the list is as long as the number of downvotes I get every time I share this.
Again, afaik.