[fredrikholm]

It's important to factor in lifestyle factors here.

By the time you hit 40, you've accumulated ~20 years of adult-life habits. For a lot of people, that lifestyle is very sedentary, missing most dietary recommendations (insufficient fiber intake, oversufficient saturated fat intake), poor sleep, frequent emotional stress etc.

As a young adult, you've spent most of your life being very active, sleeping ~10 hours a night (as a child), having plenty of downtime and playtime etc. It's why you can party hard, study hard and sleep a little; you're starting fresh.

The good news is that some of these habits are massive levers; biological age can drift decades (worst-to-best).

[N19PEDL2]

> The good news is that some of these habits are massive levers; biological age can drift decades (worst-to-best).

Do you have any good readings to recommend on this topic?

[fredrikholm]

The famous JAMA cohort study[0] of 120k people showed some 5x difference in all cause mortality and morbidity between sedentary and highly active individuals, showing effectively no upper bound.

The NHANES study[1] is another one that showed huge jumps in slowed aging with proportionally (to calories) increased fiber consumption.

There's a lot of these. I recommend Dr Michael Greger for a lot of them summarized. He's very biased towards whole food plant based diet (a type of vegan diet), but he references and cites every statement he makes and is generally a very good communicator.

There is a YouTube channel called Viva Longevity! that invites research authors and generally presents longevity/health information in a way that is very thorough and sincere.

0. https://jamanetwork.com/journals/jamanetworkopen/fullarticle... 1. https://www.mdpi.com/2072-6643/10/4/400

[throw0101c]

> He's very biased towards whole food plant based diet (a type of vegan diet) […]

A large contributor towards leaning towards plants (or awareness thereof) was probably Michael Pollan with his "Eat food. Not too much. Mostly plants." tagline:

* https://en.wikipedia.org/wiki/In_Defense_of_Food

* https://en.wikipedia.org/wiki/Michael_Pollan#In_Defense_of_F...