A man lost 20 pounds in 8 weeks. Here's how he modified his weekly Chipotle order to make it less processed — but still tasty.

• A Chipotle fan had to give up his favorite meaty burrito for 8 weeks during a vegan diet study.
• Fortunately, he was still able to maintain his Chipotle habit as a vegan.
• He just modified his order to get rid of the enriched flour and meat.

Matt Beckwith really loves his Chipotle burrito.

"I have been a Chipotle fanatic forever," Beckwith, a 52-year-old from northern California, told Business Insider. "I have eaten Chipotle once a week for maybe 20 years."

For years, he would roll up to the counter and order a chicken burrito stuffed with brown rice, pinto beans, mild and hot sauce, plus some lettuce. He didn't think much about the nutrients, he was just fueling up for his next big cycling workout.

That weekly, meat-filled burrito was the hardest thing to let go of when he enrolled in Stanford's recent nutrition study, which required him to eat only unprocessed, vegan food for eight full weeks. Beckwith was a little excited to see what it might be like to finally go vegan. "I've considered it. I've thought about it. There's a couple of well-known endurance athletes that are vegan that I've been inspired by. So I wanted to experiment," he said.

But he did not want to give up his Chipotle.

Fortunately, the dieticians he worked with during the study (featured in the new Netflix docuseries "You are what you eat") said he didn't have to quit Chipotle altogether. He just had to make a few tweaks to his usual order.

This, along with the other dietary changes Matt made during the study, led him to lose 20 pounds and lower his cholesterol into healthy territory.

Here's Matt's dietician-approved vegan Chipotle bowl:

• Sofritas, an unprocessed, plant-based meat alternative at Chipotle made from veggies and soybeans

• Brown rice

• Pinto beans

• Fajita veggies

• Hot sauce

• Mild salsa

• Lettuce

Notably, there's no warmed tortilla here. This was a big deal for Matt, who had always felt the burrito bowl to be a sacrilege Chipotle order. But this healthy eating study required him to nix all enriched flour, including his beloved burrito shell. And he got used to it.

According to Chipotle's website, the unprocessed vegan meal nets Matt about 570 calories, with 21 grams of protein, and it keeps him full for a while.

His regular old burrito order wasn't that different — warm tortilla, chicken, rice, beans, veggies, hot sauce, salsa, lettuce — but it came to 900 calories.

Recently, Matt also discovered that he loves guacamole, and so now he always orders his Chipotle with a side of chips and guac (adding 770 calories to the order).

"I am pretty bad on days I eat Chipotle," he said. "It's generally the only meal I eat all day, and that is not healthy."

Now that the study is over, Matt is keeping his weekly Chipotle tradition alive. But when he goes, he often still pulls out his trusty vegan bowl order, the same one he ordered up twice during the eight-week Stanford study.