This was different than the "best-shape-of-my-life" declarations that often come from training camp or spring training, in part because the observation actually came unprompted from offensive coordinator Pat Shurmur. When discussing quarterback Matt Barkley, Shurmur said Barkley and McCoy were the two players whose bodies had changed the most during the time off.
"Maybe it was just being away from [McCoy] for a while," Shurmur said. "He just looked good."
It turned out Shurmur was on to something. McCoy wanted to be "bulkier" last season. The results were evident, but McCoy thought coach Chip Kelly's offense required more quickness. His objective was to boost his metabolism for this season.
"Everything is about portions," McCoy said. "I'm not eating Doritos with the sauce at 12 o'clock at night. Small portions. A lot more meals."
McCoy said the weight loss was not a directive from the team's staff, which is specific about fitness and nutrition. He explained that he took the initiative. Even if his production suggested an elite running back, McCoy said he knows his own body, how it should feel, and the benefits of being bulky or light.
"Nowadays, obviously you've got to be strong, but the quicker you are, the faster you are, the better you are," said McCoy, who stands 5-foot-11. "Big guys can't get on you."
McCoy also has 2012 fresh in his mind. In 2011, McCoy rushed for 1,309 yards and 17 touchdowns and earned a lucrative contract. His production dipped the next season when he suffered a concussion. Now he is in the prime of his career, and he fears following his all-pro campaign with a down season.
"I'm trying to capitalize off that - have a real dominant year, come back with another one," McCoy said. "I have the teammates and most importantly, I have the linemen to do it. So just trying to stay in shape, stay lean, and stay aggressive."
Shurmur has noticed a difference. He said McCoy's ability to make people miss is what has generated extra yards for him, and it could also help extend McCoy's career.
"Breaking tackles doesn't affect you," Shurmur said of wear and tear on McCoy. "Getting tackled is what hurts."
At 26 years old, McCoy said he feels quicker and is forcing defenders to dive after him. There was a route he ran during one-on-one drills Thursday in which he juked Emmanuel Acho, leaving the linebacker hopelessly flailing and teammates and coaches marveling.
"I feel like I'm 23 years old," McCoy said.
He needed to stop eating like he was 23 years old to feel that way.