As an aside, I have two other interesting medical hypotheses.

First, I do not believe that metabolic syndrome (defined as a cluster of 5 symptoms) is caused by blood sugar issues. The reason is that back when I was 30, doctors were certain I was about to become diabetic. 25 years later that still has not happened and my blood sugar levels are still great (hba1c around 5%). I have ALL of the OTHER metabolic syndrome features though: low HDLs, high triglycerides, large waist circumference, and hypertension. That is why they were so sure I was going diabetic. Anyhow, my theory is that obesity eventually causes pancreatic dysfunction, and that eventually causes blood sugar issues and diabetes. But the weight where this trips is highly individually variable. And that the other metabolic syndrome features are independently caused by obesity and also other things... for example, low HDL can be genetic, as can large waist circumference, as can high cholesterol. I had hypertention since I was 9 years old and thin just like every other kid, so that can be caused by something else too. So the causation path is not that the cluster of symptoms causes diabetes, but just that it is associated. Most people with that cluster of symptoms got there by overeating which leads to diabetes, but you can have those symptoms for other reasons.

My second hypothesis is that methionine restriction extends life. This happens because methionine is the start codon. All transcription is gated by it. And so if it is in short supply, all transcription slow down in equal proportion, which essentially means slower aging. The evidence for this is that vegans live longer, and vegans don't eat high methionine foods (for example: cheese, fish). It is a simple and elegant hypothesis, but I have no way to test it, and this isn't my field of expertise. Contrary evidence would be that pescetarians apparently live longer than vegans.