From late teens to early 30s I went through phases of near to total vegetarian;
for mixed reasons of ideological influences and lack of £££$$$...

But never vegan - the vegan I flatshared with was extreme to the extent of walking city streets
bare foot in all weather for most of the year

My worse period of malnourishment was when I lived off a diet of tomato soup and dried peas for a few months
whilst saving up for music equipment.. that was stupid.

Anyway, in my late 30s when I'd taken to regular gym workouts,
I got in a debate with the gym owner,
who declared I would never find a succesdful vegetarian, let alone vegan, bodybuilder.

We didn't have internet then, so no way could I dispute that...