It only shows that he values muscles over health.
Your judgement that it is a lack of intelligence to do so is in itself, lacking.
Regardless - just because a ride goes for longer does not mean it is better.
I would like to go back to the first post: There was a plural used - yet I see only a single pic
True, I am applying subject values to another, and drawing a conclusion that it shows a lack of intelligence. And you are right, a man could have a supremely high IQ, and still do foolish things.
However, later in life, when Kevin ends up in hospital, with kidney or heart problems, I would hazard a guess that, as he lies there, and thinks to himself, he may comprehend how utterly stupid he has been.
But, the choice is his. Good luck to him.