Given the recent Mayweather/McGregor fight, a fight with a clear size difference between fighters, I thought I’d explain the art and science of weight-cutting, and how this phenomenon relates to nutrition, health, and performance.
If you didn’t see the fight or weigh-in, a few key facts include:
The fact that McGregor was TKO’d in the 10th round is actually of remarkably little importance here. I’m not usually one to say that winning and losing is not important; it is clearly a performance indicator. But in this case, I really don’t think you can measure his performance on a binary scale given all the other variables (i.e. their existing skill sets and experience in boxing). What I would like to focus on more is that McGregor had what appeared to be a slight size advantage at weigh-ins, become quite a large size advantage on the night of the fight. So how did McGregor put on what looked like 10-20 lbs. of lean mass in 24 hours?
Now, I’m speculating here that McGregor followed this standard weight-cutting process I’m about to describe. He was the larger athlete and had a what looked like a drastic increase in size from Weigh-Ins to Fight, but keep in mind that I don’t actually work with him, and don’t actually know what he weighed leading into weigh-ins or on the night of the fight. However, I know this process intimately. I’ve work with athletes on weight management, but more importantly I have personally cut-weight more times than I can count. Near the end of my wrestling career, my weight would bounce from 65kg (143lbs) at weigh-ins, to about 73kg (161lbs) in competition the next morning.
It is important to remember that I am not condoning “cutting-weight”, but merely explaining the phenomenon in hopes that a more knowledgeable athlete can make smarter choices. “Cutting-weight” can be very dangerous, and should be done so in a supervised manor, if done at all. Involve coaches in the decision, and speak with a dietitian about it. Think about the potential advantages, and how they weigh against the possible disadvantages and safety concerns of this practice before making any decisions.
Writer: Kevin Iwasa-Madge, Sports Dietitian, CSCS