Boxer Floyd Mayweather must serve the rest of his jail sentence, a judge ruled, denying an emergency motion seeking to put him under house arrest.
Justice of the Peace Melissa Saragosa disagreed with Mayweather's complaints that he didn't have enough to drink or eat and couldn't maintain his physical fitness in jail.
Mayweather lawyer Richard Wright had claimed Mayweather was enduring "inhumane conditions" at the Clark County Dentention Center, where he began serving a 90-day sentence for domestic battery on June 1.
In the emergency motion filed this week, Mayweather's doctor said that "Any lengthy period of time with an inappropriate diet, coupled with lack of regular exercise, will most likely lead to irreversible damage to Mayweather's physique.
"Such damage could and, most likely, would lead to Mayweather being unable to continue his boxing career," doctor Robert Voy said.
Mayweather was sentenced to 90 days in jail after pleading guilty to striking his former girlfriend as their children watched in September of 2010.
After a delay so he could fight last month, Mayweather began his sentence, with three days taken off for time served.
Police have kept Mayweather apart from the general prison population, saying they wanted to protect him from other prisoners, but this has kept him confined to his cell 23 hours a day.
Mayweather improved to 43-0 with a victory by unanimous decision in May over Puerto Rican star Miguel Cotto, one that assured Mayweather at least $32 million.
But Mayweather has yet to fight Filipino icon Manny Pacquiao in the bout most boxing fans have sought for several years while both men are at the peak of their skills.