[smcl]

That there are people like The Rock, Hafþór Björnsson who have a high BMI but are otherwise healthy* does not take anything away from the fact that a high BMI is a pretty good indicator that you're overweight or obese. It's an imperfect measure but realistically if you're at those Obese or above levels you're either overweight and you know it, or an outlier and you know it.

* = I suspect that a good number of guys like this are taking substances that would damage them in other ways that could lead you to describe them as unhealthy, but as another commenter said that's maybe not for BMI to measure.

[drumdance]

But are they really outliers?

As of this moment I'm 5'9", 187, and borderline ripped. People often compliment me on my physique.

But my BMI is 27.6, which makes me "overweight."

[smcl]

Yes. As are you. Put it this way, BMI is used to calculate that 35% of people in the USA are obese and 34% are overweight. Is that because there are lots of people who are borderline ripped and BMI is flawed, or is it because there are lots of overweight people? Which do you see more of when you walk down your average street. If it's the former then I will concede that I am incorrect and that you're statistically normal, but we both know it's the latter and it's to your credit that you're likely to be very healthy.

Note: I'm making an assumption you're in a western country like the USA or the UK