Lordy - you’d think they’d be grateful for the blood.
I give blood and I just don’t tell them, I take a stock cube and a salami stick for after and say no thanks to the carbage and the OJ.
It remains depressing to have supposedly trained medical people talking utter pish but unfortunately, they’ve learned a dogma and not everybody is, frankly, all that bright.
Go donate at a different centre if you really believe in it and let the steam out of your ears here - you’re among friends.
We’ve all had these conversations - usually in my case with somebody who looks in considerably less good shape than I know I’m in, who is happily telling me that I’m killing myself.
Fuck 'em! Keep calm and keto on.