"I'm going to make him pay for it," Weidman told ESPN.com. "Cheaters never prosper. I'm going to make that little saying stick."
The incident occurred shortly after the two made weight at the MGM Grand Garden Arena in Las Vegas. Weidman (12-0) is scheduled to defend his 185-pound title against Belfort (24-10) on Saturday.
Weidman, 30, said his discontent stems from the results of Belfort's out-of-competition drug testing leading up to the fight.
According to test results obtained by ESPN.com, Belfort submitted to multiple urine and blood tests prior to the fight. The Nevada State Athletic Commission ordered the tests.
On March 16, Belfort's urine test produced a testosterone level of 1,200 ng/dL. On April 28, his tested level was 500 ng/dL. Most labs consider a range of 348 to 1,197 ng/dL to be normal.
Weidman's levels on March 30 and April 27 were identical, at 370 ng/dL.
The levels, along with Belfort's testosterone-to-epitestosterone ratios, are all acceptable by NSAC standards, and the fight will happen as scheduled. The levels are, however, somewhat surprising given that Belfort, 38, has previously claimed he suffers from low testosterone. In 2013, he was approved for testosterone-replacement therapy (TRT) before three fights in Brazil.
"I found out his testosterone scores throughout his camp," Weidman said. "They went from 500 to 1,200, which is, like, extremely, extremely high. This is a guy who was on testosterone replacement therapy because he needed it for so long, yet his testosterone is four times the amount of mine, and I'm 10 years younger.
"So he's cheating, and I called him out on that."