I mean, I know basically how many beers will get me drunk and am well aware of the times I drink. Coffee, though? I read tons of folks saying it affects them... But it feels similar to the folks saying vitamin d improved their life. I am not claiming they are false, but I am claiming I don't feel it.
I don't have a source for this, but I've heard that coffee legitimately does affect some people differently. Because some people have a gene for an enzyme that metabolizes caffeine very effectively, and others don't.
Which, that may not even be true. In which case, I don't mind. It was all by way of illustrating, be careful trying to extrapolate from a sample size of 1. In fact, just don't do it. Conversely, don't assume an aggregate statistic accurately describes anybody in particular.
I don't know about grapefruit and caffeine specifically, but it's at least a great example from a tongue-in-cheek perspective. Grapefruit has a kind of ridiculously long list of drug interactions. It seems like pretty much everyone I know over the age of 65 is under doctor's orders to stay away from it.
I mean, I know basically how many beers will get me drunk and am well aware of the times I drink. Coffee, though? I read tons of folks saying it affects them... But it feels similar to the folks saying vitamin d improved their life. I am not claiming they are false, but I am claiming I don't feel it.