I cannot say much about the low protein diet but do eat a balanced diet and still suffer from long covid. Its the unwelcome visitor when your system is a little low. I suffer the headaches and the tireness especially in the afternoon. In between one or two good days, so I keep on trying different things. Walking helps but I suspect it is just getting outside changes my mood.

I think that might be true. I hardly eat protein and it's been 3 weeks and I still feel awful. The rest of the household recovered within 10 days. 😑