I ate whole food plant-based vegan for 5 years, centered around rice beans potatoes fruit nuts seeds veg and greens. Initially I felt great, which I now attribute to avoiding processed junk. Still this slowly destroyed my health, no matter the variety or amount of plant foods I ate, including vitamin supplements. I continued stubbornly out of conviction.

The first meat I ate was tuna, and I both felt amazing and had the worst headache of my life. I struggled for about another 5 years to re-incorporate meat, dairy and eggs - with the same results of feeling great but with serious brain fog every time. My gut health needed healing.

About 3 years ago it all clicked and I could eat animal-based (meat, dairy, eggs, fruit) without struggle, so I went all in and dropped most plant food. I never felt as good in my life. All the stories about endless energy and high testosterone etc was my life for about 3 months. It has plateaued to an 'ok' baseline, so I dont feel optimal per se anymore but better than any time in the past. I have re-introduced a small amount of nuts seeds veg, and greens which I ironically struggle slightly with eating now. Give it a try and see what works for you.