But when the Cardinals right-hander took his physical last week, the proof was in the three digits that appeared on the scale: 239.
''Where's your other half?'' pitcher Adam Wainwright joked.
Lynn dropped 40 pounds during an offseason nutrition and conditioning program in which he restructured his diet while working out six days a week.
''Lance Lynn did himself a huge favor,'' Cardinals manager Mike Matheny said. ''He took a huge step in his maturity, in taking control of his career and realizing, `I'm going to do everything I can (to become better).''
Lynn, 25, was not happy with the way his season ended. He had replaced an injured Chris Carpenter in the rotation and was 18-7 with a 3.78 ERA in his first full season in the big leagues. His hot start landed him a spot on the NL All-Star team.
But those numbers could have been even more impressive. After an 11-4 record and 3.41 ERA before the break, Lynn's ERA ballooned to 6.66 in August and he was demoted to the bullpen.
Lynn was asked what motivated him to start the health program.
''To be better than last year,'' he said. ''I think I left some things on the table last year and I didn't want to do it again this year.''
Lynn, who is 6-foot-5, was about 280 pounds by the end of the season. Before spring training, Matheny told Lynn he should take the approach that he has to earn a spot in the rotation and not believe one is waiting for him even after Carpenter was lost for the season because of an ongoing nerve issue in his right shoulder.
''I know it made Lance a little frustrated,'' said Matheny, adding that he anticipates Lynn taking advantage of the situation.
Lynn has a different outlook.
''The way I approach it is it's my spot to lose,'' Lynn said about one of the two openings behind Adam Wainwright, Jaime Garcia and Jake Westbrook. ''I was an 18-game winner last year with an All-Star appearance. I got to do a lot of things to lose the spot, in my opinion.''
The offseason transformation began soon after the Cardinals lost Game 7 of the NLCS to the Giants.
''I learned how to eat,'' he said. ''As a kid you eat whatever you can get your hands on. Now I have to opportunity to know what I'm putting in my body and know what's good and what's bad. There was no target weight loss, not even talk of weight loss. It was all about getting healthier and being stronger. I wasn't paying attention to the weight I was losing until I came in here and they showed me where I was at.''
The Cardinals will be looking at some of their prospects and young pitchers when spring training games begin this weekend. But by the start of the regular season, Lynn is expected to be slotted into that fourth spot.
The difference this season is he's expected to remain there.
''It's great to see,'' general manager John Mozeliak said about Lynn's weight loss. ''Where he was to end the season last year this is ultimately going to help him as far as endurance and being able to go the long haul.''