When ex-New England Patriots star Rob Gronkowski is in fighting shape, he stands at 6’6 and weighs about 265 pounds of muscle. But a recent appearance on Showtime’s “100 Percent,” the ex-NFL great appeared noticeably slimmer.

Yahoo Sports ran a headline that screamed, “Rob Gronkowski’s Weight Loss Seals it: He’s Retired.”

Dr. David Chao, a former NFL team doctor, posted a before-and-after picture of Gronkowski, and wrote, “Must be on a different #TB12 program now.” The TB 12 program is what Tom Brady refers to as his diet that keeps him on top of his game. The diet is based mainly on plants and lean proteins that claims it will make your body less acidic, according to Business Insider.

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Yahoo Sports reported that Gronkowski used the method during his playing days. The report pointed out that it is not uncommon that an ex-NFL player sees dramatic weight loss upon retirement. It takes a lot of energy to maintain the muscle mass of many of the players.

Gronkowski finished his career with 521 regular-season catches over nine NFL seasons for 7,861 total yards (an average of 15.4 yards per reception) and 79 touchdowns, the third-most by a tight end in NFL history behind only Antonio Gates (116) and Tony Gonzalez (111). His 12 career postseason touchdown receptions are the most by a tight end in NFL playoff history and his 81 career postseason catches are the most among tight ends.

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Brady and Gronkowski hooked up on 78 TD passes, the second-most between a quarterback and a tight end in NFL history behind only Philip Rivers and Gates (89) and the fifth-most between quarterbacks and all pass-catchers.