As an actual athlete (not in cycling though) the advice I was always given, and the advice I give other people is to stick to what you know.
You eat ‘x’ and ‘y’ food all year round, your body is used to that. Don’t go changing your diet and start adding in ‘z’ mere days before a big event. You’ve spent the previous 358 days eating normally, there is no need to confused your body, and potentially eat something it doesn’t agree with on those last 7 days.
This is the reason Usain Bolt famously ate chicken nuggets before his 100m WR in 2008, not because they are an undiscovered superfood, but because he was in a foreign country, and McNuggets were a familiar food source.
However if you were to experiment in small amounts over a longer period of time, that could be beneficial, but that’s another topic.