Me too, I'm 37, and I did a radical diet change -- No sugar, no carbs, no dairy, no gluten. Only meat and vegetables and fish and some fruit.

After a year of this I've dropped 20kg, and my mental clarity is back where it was when I was early 20's.

I think it was mostly the no sugar that did it.

Exercise too - I walk 2-5 km a day

Oh and cutting down what I eat too -- I only have 1 meal a day, and a smoothie in the afternoon

That's pretty radical on the diet. Was it difficult to adjust? I'm pretty thin as it is so I'd be worried I'd waste away!

I did a radical diet change, too. I'm wired where I can just do that. I've read most people can't and trying often leads people to failure. If you aren't wired to just pivot on a dime you might try a system that works for you.

My major diet change was to eat like the healthiest of the Blue Zone folks. I wanted great energy now and longevity of it and my life. A diet that gives me energy now but leads to heart disease wouldn't cut it.

For that, I went plant based whole grain.

How much you eat matters, too.

A good technical book on diet is The Proof is in the Plants [1]. It covers what we need in our diets and why. For example, how much selenium do we need and what are sources of it. Despite the book title talking about plants it also covers meat and dairy. Everything covered in the book is based on the latest scientific research. It's written by a dietitian who can reference the studies.

[1] https://www.amazon.com/Proof-Plants-science-plant-based-plan...

Yes it was difficult - giving up sugar was very tough, everything has sugar in it and the cravings were strong.

After a month though my taste buds changed, and I really enjoy the taste of meat and vegetables now.

Yesterday I had the opportunity to eat some vegan ice cream, and I thought I would treat myself to a couple of scoops in a cup thing, and after just 2 bites it was sickly sweet, the amount of sugar made me feel really ill, and it felt like I was eating poison, so I threw it away.

Quite interesting. I do miss some foods (pizza :( ) but the mental clarity alone is worth it.

Vegan processed foods are often just as bad as regular processed foods. So sweet. The vegan label may mean there's no meat or dairy but it doesn't mean it's good for you. Most processed food isn't.

Plant based whole grain is usually a diet of the real foods themselves. Take a bean burrito that someone makes fresh. Or a stir fry using fresh veggies. So different from processed foods.

I still eat pizza. Love them carbs :)

Similar results for me. Was basically stuck in bed most of the day. Finally went AIP diet, which is roughly the same diet. Few months later I was kayaking a couple times a week.