Fighters like it's said to? People cite Duran losing 50 pounds or so as the reason for his performance in the second Leonard fight... Jeffries losing 100 pounds for why he was so bad in the Johnson fight... But Foreman came way down from well over 300 to win back a portion of the HW title, fighting at a far older age than Jeffries, for an entire 10 year second career. Jeffries fought... what, less than 20 fights before retiring? How much mileage could he of really had on his body? What Fitz did to his face? Look at what Stewart did to FOREMAN'S face.
Having to drop lots of pounds quickly in order to make weight can ruin a guy without a doubt. That kind of crash dieting can make a fighter so weak that he totally loses his effectiveness in the ring. I know of many examples in boxing history.
Well, Jeffries and Foreman both had a long time to do it. Moore did it for years and years and seemingly never suffered for it.
I'm not so sure that it's weight loss, as opposed to radical and dramatic weight loss that causes problems. If a fighter starts slowly but surely dropping weight months out before a fight, he should be able to retain his strength and stamina because his body will adjust over time. If he starts dropping a lot of weight mere weeks before a fight and is still desperately struggling to make weight a day or two before he weighs in, he's got major problems. I believe that there should be no reason, other than in exceptional cases, why a fighter cannot make weight well before fight time. It's usually indiscipline that gets them into trouble.
I know it from me personally, it´s really very hard, unhealthy (especially for your bloodstream) and it steals your power/ strengths.
Dehydration is the killer. If a guy goes into the ring with unhealthy low levels of fluid in his body, and gets into a war, he can die. Heat exhaustion, a dry brain, and permanent damage to other internal organs, can be the results.
Hence despite the odd sad exception and despite being the most powerful punchers; Heavyweights tend to die a lot less than the lighter weights. Yes Regis was killed and Page badly hurt, but as a rule the Heavies are the safest. Thus surely proving like Sonny's jab suggests it is the combination of big (quick) weight loss and a a hard fight that can lead to terrible situations.
It has a lot to do also with how much time you take about it. Losing weight is something you have to do gradually, step-by-step, and not in a matter of a few weeks. I sure as hell know about that first-hand. It really KILLS you!
