Could Conor Benn Really Gain 32 Pounds in 10 Hours? What the Research Shows
Conor Benn officially weighed 146 pounds on Friday morning for his WBC welterweight title fight with Ryan Garcia. Roughly 10 hours later, a video posted on social media showed a digital scale reading 178.4 pounds as Benn stood on it in his Las Vegas hotel room.
If both measurements accurately represented his bodyweight, Benn had gained 32.4 pounds, or 14.7kg, in around 10 hours.
That is an increase of 22.2 per cent from his official weigh-in weight.
Rapid weight gain after a weigh-in is normal in professional boxing. Fighters deliberately reduce water, glycogen and gastrointestinal contents to make weight, then begin restoring them as soon as they leave the scale.
What makes Benn’s apparent gain unusual is the size of it and the short period in which it supposedly occurred.
What professional boxers normally regain
The strongest direct comparison comes from a 2022 study of 399 male professional boxers using official California State Athletic Commission data.
Researchers found that 97.5 per cent gained weight between the official weigh-in and competition. The average increase was 4.4kg, or 9.7 pounds, equivalent to 7.2 per cent of weigh-in bodyweight.
Boxers competing on international-level promotions averaged 8.0 per cent, while 20.6 per cent of the full sample regained at least 10 per cent.
Applied to Benn’s 146-pound weigh-in, a 7.2 per cent increase would put him at approximately 156.5 pounds. An 8 per cent gain would take him to 157.7, while a 10 per cent increase would put him at 160.6.
The personal scale in Benn’s hotel room showed 178.4.
A separate study of 142 boxers across 71 IBF title fights found an average regain of 3.8 per cent, with the largest individual increase recorded at 9.3 per cent.
Those measurements were taken at the IBF’s secondary weigh-in 12 hours before the fight, so they are not a direct comparison with a fighter’s eventual ring weight, but they provide another set of official professional-boxing data.
Research from other combat sports has recorded more aggressive cutting and recovery.
A 2019 systematic review covering 16 studies and 4,432 combat-sport athletes found recovery periods ranging from three to 32 hours. The largest rapid weight gain identified was an average of 11.7 per cent in a study of seven UK MMA fighters.
That seven-athlete MMA study found the fighters had lost an average of 8.0 per cent before weighing in and regained 11.7 per cent over approximately 32 hours. More than half were dehydrated at the weigh-in and 43 per cent were classified as severely dehydrated.
It was an extreme and very small sample, rather than a normal benchmark.
Even so, its average rebound was roughly half the percentage implied by Benn’s scale reading, despite a recovery period more than three times as long.
What would a 32.4-pound increase involve?
The scale difference itself is straightforward.
To move from 146 to 178.4 pounds, Benn and whatever he was wearing at the second measurement had to be 14.7kg heavier than at the official weigh-in.
Some of that difference can be explained by clothing. Benn weighed in under official conditions on Friday morning but was wearing a T-shirt and sweatpants when he stepped on the personal scale later in the day.
The rest would principally come from fluid, food and the restoration of glycogen and its associated water.
The International Society of Sports Nutrition’s 2025 position stand on combat-sport weight cutting recommends beginning post-weigh-in rehydration at approximately one to 1.5 litres per hour during the first one to two hours.
It also estimates that deliberate glycogen depletion can account for around one to two per cent of body mass during a cut, with low-fibre dietary manipulation capable of reducing another one to two per cent. Acute water loss in the final 24 hours is optimally kept to around two to four per cent when properly supervised.
All of those losses can begin reversing after the weigh-in.
Glycogen restoration is particularly relevant because stored carbohydrate carries water with it. Experimental research examining muscle glycogen and water recovery found approximately three grams of muscle water stored per gram of glycogen under one rehydration condition, supporting the commonly cited relationship between glycogen restoration and increased muscle water.
That helps explain how fighters can put substantial weight back on without adding new muscle or body tissue.
The ISSN position stand also recognises that fighters making significant cuts may seek to regain 10 per cent or more after weighing in.
But the figure shown on Benn’s scale would require a net increase of roughly 1.47kg for every hour of the reported 10-hour period.
That is net weight retained, not simply fluid consumed. Food and drink intake would have to account for continuing losses through urine, respiration and perspiration during the same period.
A 32-pound rebound is therefore not merely a large version of a routine post-weigh-in recovery. If both scales were accurate, it would represent an extreme result compared with the published data.
Two measurements under very different conditions
There is another problem with treating 146 and 178.4 as directly comparable numbers.
Benn’s first weight was recorded by the Nevada State Athletic Commission on its official scale. The second came from a personal digital scale in his MGM Grand hotel suite.
The measurements were not made on the same equipment, under the same conditions or in the same clothing.
There has also been no independently reported calibration check of the hotel scale.
That does not establish that the 178.4 reading was wrong. It means only that it should not be treated as equivalent to an official commission measurement.
There is also an important distinction in how the percentages are expressed.
Going from 146 to 178.4 represents a 22.2 per cent increase relative to Benn’s weigh-in weight. If 178.4 were instead treated as his fully restored weight before cutting, dropping from 178.4 to 146 would represent an 18.2 per cent reduction from the heavier figure.
That would still be an exceptionally large total weight reduction.
The ISSN guidance does not suggest that an 18.2 per cent acute dehydration cut would be appropriate. Its recommendation for acute water loss in the final 24 hours is approximately two to four per cent, with additional reductions potentially coming from glycogen depletion, lower gastrointestinal contents and earlier stages of the cut.
More severe cuts have been documented, including the seven MMA fighters who lost an average of eight per cent before weighing in. The researchers described the dehydration practices involved as potentially harmful.
Benn’s recent fighting weights do make a substantial cut to welterweight plausible. He weighed a career-high 159¼ pounds for his rematch with Chris Eubank Jnr and has said he intends to return to at least middleweight after facing Garcia.
The issue is therefore not whether Benn had considerable weight to regain after making 146 pounds. He almost certainly did.
It is whether an official 146-pound measurement and a personal-scale reading of 178.4 approximately 10 hours later can be interpreted as proof that he regained 32.4 pounds of body mass during that period.
Published professional-boxing data puts the average rebound at 7.2 per cent. Only around one in five boxers in the largest available study regained at least 10 per cent. One of the most extreme MMA groups studied averaged 11.7 per cent over approximately 32 hours.
Benn’s apparent increase was 22.2 per cent in roughly 10.
The video shows what his personal scale displayed. Without a second calibrated measurement under controlled conditions, it does not establish that Benn physiologically regained 32.4 pounds in one afternoon.
Anyway, enough about glycogen and fluid balance. Enjoy the fight tonight.
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