"I think it's about educating yourself and being open to it. It's something I really wanted to do. For sure, it hasn't been easy to learn new things and new ways, but I've felt so good for the last year and a half. It's been such a great decision."
It is a diet of fruits, vegetables and grains, while minimising eating animal products and processed foods. It is a growing trend among elite athletes, including tennis stars Novak Djokovic and Venus and Serena Williams, and Kyrie Irving of the NBA.
Since his diet change, Hamilton has won 19 races and last season became only the third driver in Formula One to win five world championships. He is 10 wins away from equalling the record of 91 held by Michael Schumacher.
Hamilton works closely with performance coach Angela Cullen, and his diet transition has changed his understanding of food and nutrition.
"I'm looking at what I eat as fuel now as an athlete, rather than just eating because I'm hungry," he said. "I'm constantly working with Angela, who is with me all the time. We're looking at ingredients of different things that I'm eating.
"Sometimes I'm just having room service in a hotel, and I don't know what to eat, so then I have to hit someone up or read online. Maybe there's a restaurant around you can get a delivery from, or maybe I can get the chef to whip up something different that they haven't done before."
The challenge of looking after a driver's nutrition on a race weekend typically lies with their trainers. Rupert Manwaring, a performance coach, serves that duty for McLaren driver Carlos Sainz.
"You want to make sure that they're getting fueled correctly with the right amount of energy at the right times," Manwaring said. "It's not just the energy element, but the micronutrients as well and vitamins that help with their immune system.
"They're under a lot of stress, not just physically but also with the travel element. We're making sure they get all the good, necessary nutrients to perform and stay healthy."
Manwaring said that working with a vegan athlete would require more planning to avoid deficiencies in macronutrients. Fats and carbohydrates are important for a driver's energy output, while protein helps build muscle mass required to drive the cars and handle high G-forces.
"They have to take a little bit more care and a little bit more planning with what they have," Manwaring said. "You can use protein supplements, but you could combine grains, beans and different legumes, which still have proteins and various amino acids in them.
"You would have to combine one with the other to make sure you get the complete set of nutrients which are important for what you need on a daily basis."
A plant-based diet also brings other nutritional advantages to athletes.
"You're likely to have more fiber," he said. "You're likely to replace meats with fruits and vegetables, which will mean you're higher in vitamin C and vitamin E, which are good for keeping healthy."
Romain Grosjean of the Haas F1 Team, who is known for his love of food and who even published a cookbook last year, is skeptical about a plant-based diet.
"If you're an athlete, I think being vegan is actually negative," Grosjean of France said. "From what I know, some endurance athletes going vegetarian or vegan had to stop their vegan diet because they couldn't get enough nutrition for high-demand exercise.
"It's not a secret that I love triathlon, I love cycling and doing long sessions. I do need to eat as much food as I can, and a varied range. I fully respect veganism and some of the aspects, but I won't go there."
Manwaring disagrees, saying that a vegan diet would not be a drawback as long as the required nutrients are made up in other areas.
"Common consensus is that it is fine," he said. "An athlete is not going to be compromised if they go down the vegan or plant-based route. It just means that they must take a little bit more care.
"At the moment, there is not one short, hard, fast answer for what is the perfect diet. You can find the right solution in a number of different ways, and athletes who are doing vegan diets are able to compete at a very high level."
Manwaring said the best diet ultimately came down to the athlete's preference, which would shape how their nutrition would be managed.
"It's important to give the athlete that freedom to choose," Manwaring said. "I think an athlete can gain a bit of confidence in going in one direction. Digestion is quite closely linked with mood as well.
"If you find something that works for you and it makes you feel good, in a competitive situation, that's really important."
Hamilton's interest in his new diet led to him become a co-owner of a plant-based restaurant, Neat Burger, in London this month.
"I'm dying to go there," he said. "I remember going to the taster. I'm very particular in my food, and it tastes so good."
Hamilton said his diet was working on and off the track.
"It's only going to continue to get better as my body gets more and more used to it, and as I understand it better as well," he said.
"I can improve the amount that I'm eating and when I'm eating. I plan to continue on this route. And I definitely believe it has had a really good, positive impact on my daily life, in terms of the energy that I have and the feeling that I have when I'm at work. I'm very rarely tired.
"For me, it has been a life changer."
Written by: Luke Smith
© 2019 THE NEW YORK TIMES
