At 41 years old, in his 19th season, Brady is preparing to play in another Super Bowl, the ninth of his career and fourth in five years.
Brady credits his longevity to his regimented lifestyle.
In recent years, Brady has shed light on his diet, exercise and recovery habits, and overall lifestyle in the form of a book, "The TB12 Method," a cook book, apparel, and documentary. He has created the regimen and business with his friend, business partner, and trainer, Alex Guerrero, who Brady cites as an influential figure in his life.
But how exactly does Brady employ the TB12 method to get results in his day-to-day life?
Learn more about one of the strictest lifestyles in sports below.
Sam Belden contributed to this report.
At 41, Tom Brady is the oldest starting quarterback in the NFL, and still one of the best.
In a 19-season career, he has won five Super Bowl rings and has been named to 14 Pro Bowls, including the past 10 years.
But staying at the top of your game for nearly 20 years isnt easy in fact, Brady is a bit of a fanatic when it comes to his physical fitness.
He is meticulous about his workout routine...
...and even more meticulous about what goes into his body.
Brady divulged some of his secrets in his book,"The TB12 Method: How to Achieve a Lifetime of Sustained Peak Performance."
Published in 2017 the book is filled with diet, exercise, training, and recovery tips ranging from the conventional, inventive, and questionable.
The TB12 Method is built on 12 different principles, from balance and moderation to promoting anti-inflammatory responses in the body.
But the most important concept may be the first one on the list: pliability. Brady calls it "the missing leg of performance training."
According to Brady, conventional weight training leaves muscles short and dense due to the constant contractions. He believes that long, soft muscles lead to peak performance.
Brady is a big believer in working out with resistance bands, rather than conventional weights (though he doesnt eschew weights).
In a documentary series, "Tom vs. Time," Brady gave a behind-the-scenes look at the intense massages he gets with Guerrero to keep his muscles long and soft.
And Brady works hard for maximum pliability. His incredibly regimented daily routine has garnered attention in recent years, with numerous other players attempting to emulate it.
That includes Rob Gronkowski, the Patriots tight end.
Brady does put in the work behind the scenes, often arriving in the weight room by the crack of dawn. Former teammate Rodney Harrison once joined Brady at the gym at 6 a.m., only to be greeted by a sarcastic, "Good afternoon."
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As a result, Brady says his body is better conditioned for the impact of an NFL game.
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He said his brain is now wired for contact, and that when he takes a hard hit, he barely feels it because his body "disperses" the forces.
But as hard as Brady works out, its his diet that really throws people for a loop. With a litany of strict rules regarding what and when he can eat, hes the NFLs resident ascetic.
For example, Bradys diet includes a ton of fresh vegetables but only certain ones. While carrots and dandelion greens are staples, he avoids nightshades, a group of veggies that includes tomatoes, peppers, mushrooms, and eggplants.
And those arent the only foods Brady refuses to eat. White sugar, white flour, and dairy are nowhere to be found in his kitchen. He "rarely" drinks alcohol, and hes never even tried coffee.
Hes not big on dessert either for him, avocado ice cream is a special treat.
Bradys wife, Gisele Bundchen, and his children are also adherents to the strict diet. The kids almost always eat the same meals as their parents.
Staying hydrated is another bedrock of the TB12 Method. Brady says he drinks between 12 and 25 glasses of water a day, or up to 2.5 gallons.
He also adds electrolytes to everything he drinks. He even sells his own electrolyte solution.
He has some odd ideas about the benefits of staying hydrated. While Brady suffered frequent sunburns as a "fair-skinned Irish boy" growing up in California, he says he doesnt get them anymore because of all the water he drinks. "I always hydrate afterward, too, to keep my skin from peeling," he wrote.
But many experts reject the water-as-sunscreen life hack. Jodi Stookey, an Oakland-based hydration epidemiologist, said she had "a small chuckle" when she read the passage, while David Leffell, a dermatologist at Yale University, called it "ridiculous."
Others have questioned the strictness of Bradys diet, which he purports to be 20% acidifying foods and 80% alkalizing foods. "What you eat doesnt affect blood pH," said the exercise physiologist Stacy Sims.
Because of the sunburn claim and others like it, many have serious doubts about The TB12 Method as a whole. A New York Times headline said the book was "hefty but short on science."
It has led to some negative publicity for Alex Guerrero, Bradys longtime personal fitness guru and co-collaborator.
Guerrero has a checkered past. In the early 2000s, Guerrero, acting as a doctor, developed a nutritional supplement known as "Supreme Greens," which he said could cure ailments like AIDS and cancer. Eventually, the Federal Trade Commission found the product to be ineffective and barred Guerrero, who holds only a masters degree, from ever again referring to himself as a doctor.
But even with Guerreros checked history, Brady sought his help, and he has put on a historic display of consistency and longevity. The quarterback said the training is "huge, huge reason why Im still playing."
Brady and Guerrero even opened a gym together. The TB12 Sports Therapy Center is located in Foxborough, less than a mile away from Gillette Stadium.
Brady and Guerrero sell other items designed for recovery, too, like special pajamas...
... to foam rollers and "vibrating spheres"
Brady is unwavering in his commitment to his health, but his lifestyle may not be for everyone. "Its unique to each individual. Its a very customized program for each person because everybodys body type is different," Guerrero said of the TB12 Method.
Belichick certainly isnt an adherent. "We see Tom every day," he said when asked if he would purchase the TB12 Method. "I dont really feel like we need to read a book."
Brady has said he does take moments to enjoy his life, whether its with a cheat meal or a day off. But he said he also makes sacrifices and stays diligent with his training and diet to stay at the top of his game. Its clearly working.
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Now, take a look at the quarterbacks teams are kicking themselves for drafting over Brady....
WHERE ARE THEY NOW? The 6 quarterbacks taken before Tom Brady in the 2000 NFL Draft >
