Ok, so I was googling myself the other day, as you do, and one of the sites that popped up was a spam blog with a post “how do boxers lose weight so fast”? Obviously it was just junk, but let’s see if I can beat that site to the top of the google results by writing a real post about how boxers lose weight so fast.

So here we go. It depends what one means by “lose weight so fast”? If you mean why most of them are so ripped and defined in the fights, well it’s because they train hard and eat healthy, nothing more. And if you didn’t know this, the rest of this little post ain’t gonna be too important to you.

Do you mean how do they drop anything from 10 pounds upwards right before the weigh-in at a fight? Note: most the top level competitive boxers and MMA fighters (etc.) tend to be heavier than their weight class on a normal day, but drop their weight right before a fight, to squeeze in the weight class just below.

How they do this is by basically dehydrating themselves for a while, and not eating for a period. Basically they empty their body of food and water. It’s often done by wearing some air-tight clothing and going for a run, and then sitting in a sauna, etc. A lot of weight will be lost through sweat.

This lets them drop quite a bit of weight for the weigh in, and right after their weight’s measured, they’ll go and fill up on nutrients, food and water (otherwise they’ll be pretty wasted for the fight!).

This gives them an effective, say 10 pounds, of muscle more than they really should have in their weight class – a nice little advantage over anyone who naturally falls into the weight class.

For example there’s two boxers, A and B, and the target weight class is 80kg or under. A trains and maintains his weight at about 77-80kg range. B trains and maintains his weight at around 85-87kg. Weigh in time: A casually makes it. B spends 24 hours leading up to it, losing weight, sweating, not eating much, etc., makes it to weigh-in at 80kg. The fight is 18 hours later. B eats and drinks and gains his weight back, but too bad for A there’s no more weigh-ins, he’s up against a heavier, and probably stronger opponent. (B just has to watch out that he doesn’t lose strength through being too dehydrated).

As simple and unhealthy as that.