Yesterday, reading in my newspaper I discovered an interview with a professional boxer (at the end of his career). He said preparing for an upcoming fight has been really hard... getting body weight down and all that.
What caused my surprise was another remark from the boxer. When he is well-trained, low weight, he has a really low body fat values of, say, 5%, but he does not really like this. He said that during this time, he is easily irritated, exhibits uncontrolled anger and tends to be a more unloveable person.
So is this an individual trait or can this be generalized? So getting low body fat could have undesirable effects on the temper or mental state of the athlete? Is there a medical explanation for this? How would a sports-psychologist comment on that?