He said in his news conference that losing the weight was a personal goal he set after the season and not something the Panthers made him do.
"It was just a personal goal that I set for myself. I'm not going to go into what it really meant because looking at my body from afar you really couldn't tell," Newton said. "Being that I lost the weight, nobody really could tell, either.
"It's just me challenging myself to have an edge going into the season."
Newton was asked what he thought of Michael Vick's recent boast that the Philadelphia Eagles quarterback was the fastest signal-caller in the NFL. Asked where he'd put himself in that conversation, he said he was "taking my name off that ballot."
Newton said he believes the distinction of fastest quarterback is "between RG III [Robert Griffin III], Colin [Kaepernick] and Michael Vick."
"I don't want to be the fastest quarterback, I just want to be the guy that can't be caught in the open field," he said. "Because if you get caught in the open field, that means you're not doing something right, and that will be talked about in the locker room."
Another highlight of Newton's news conference came courtesy of left tackle Jordan Gross, who took the opportunity to photobomb the quarterback, sneaking behind him and doing poses behind Newton while he was being asked a question.
Newton just smirked afterward, asking "what was the question?" to laughter from reporters in attendance.