The New York Giants’ 30-year-old running back Rashad Jennings is only several hours removed from a gut-wrenching loss to the Philadelphia Eagles when we hop on the phone. Jennings had one of his best games of the season against the Eagles, one of the Giants’ most hated rivals, registering 63 yards on 13 carries; of course, his stat-line doesn’t single-handily influence what the G-men rack up in the wins column, leaving his squad at a mediocre 3-3 on the season.

But that disappointment is last’s night news. He’s already onto the next game, prepping for another divisional rival, the Dallas Cowboys. To be at peak-form for Sunday—as well as for the practices, meetings, and training sessions that accompany being a professional athlete—Jennings adheres to a strict, unorthodox diet that’s helped him weather seven seasons as the NFL’s most bruising position. What’s so unusual about jennings’ diet? He’s gluten-free. A pro-ball player who refrains from eating things like, well, bread—what gives?

“In high school I was a 270-pound, overweight kid with asthma who was a fifth-string running back,” Jennings says. “I didn’t have it all together.” A high-school coach eventually called him out on his weight, which prompted a revelatory experiment (more on that below) that allowed Jennings to surmise the disastrous effects that fast-food played on the body. From there, he swore off bread, dairy, and all fast-food, slowly eliminating the items from his diet and replacing it solely with vegetables, fruit, and other fresh foods.

The rest is history: Jennings went on to play D-I football (college ball’s highest level) at the University of Pittsburgh and Liberty University, before being drafted by the Jacksonville Jaguars in 2009. Now, besides being a reliable member of the Giants, he’s also advocating for people to ditch animal-based foods for the Meatless Monday campaign, and inspiring kids to practice healthy eating habits with his Rashad Jennings Foundation.

We asked Jennings to break down his diet, why and how he maintains it, and how it’s possible to play one of the most demanding sports at the highest level while abstaining from a lot of the sh*t we eat on a daily basis.

He has his mother and one fateful experiment to thank for his dietary switch

“[In high school] I took a McDonald’s hamburger, some cheese, milk, and bread and placed it on the counter. Then, on the opposite side, I laid down some chicken, some lettuce, and an unpeeled banana. (Bless my mom for letting me do this.) Three days later, I came back and saw that the hamburger, cheese, milk and bread were all still thick and hard. Meanwhile, the chicken started deteriorating a little bit, as did the banana and lettuce. I asked myself, What’s going on?. If that’s what happens on the outside, then I wonder what happens when that food is inside my body. From that point on I started not to eat anything that didn’t deteriorate by my saliva or the air hitting it.

It requires dedication to balance being gluten-free and a pro football player

“It’s tough sometimes. I travel with all my food and literally go nowhere unless I’ve already eaten at home or I have a meal packed—it’s my fuel. Everything that I eat, and it’s three-square meals every day, I make sure it’s fuel-efficient. When I first started, it wasn’t the easiest. But gradually I started picking it up. I learned how to shop, what to stay away from, and I learned that I’m not the best cook. And you know, I just kept at it. The hardest thing I went through was dealing with menus. I’d go out to eat and had to figure out what was permissible. What it comes down to—whether you’re at a restaurant or cooking in the kitchen—is you need a protein, simple carbs (like baked potatoes or sweet potatoes or gluten-free pasta), and a simple vegetable (like broccoli, carrots, squash). And that’s very easy to get.”

You don’t have to make Whole Foods money to eat well

“For people worried about money, buying in bulk is key. My first year in Jacksonville I would shop for the whole entire week. On Saturday or Sunday after games I would have some friends over to play board games and cook a ton of food for the whole entire week. I would portion it out and then freeze it. That way I didn’t have to think, You know I’m out I’m at work, I don’t feel like cooking, and I’m going to order out. And then when I look at my bank account I’ll find I’m actually saving money. In the end, you’re either going to spend money in the kitchen or you’ll going spend it in medical bills if you’re eating out at fast-food spots all the time. You make an investment—it’s up to you what you spend it on.”

Rule of thumb: Don’t count calories

“I don’t count calories. I’ve tried it before and found that it doesn’t work for me personally. I eat as much as I want or as little as I want, depending on the day. But I’ve just made sure that everything is fuel-efficient—that’s more important to me than counting calories. Especially when you’re working out, you don’t want to become a robot to your diet. It’s a lifestyle. Enjoy it.

There is no such thing as “cheat days”

“Nah, I don’t have a cheat day—well, if I have anything that resembles a cheat day, I’ll go out and get sushi. But for the most part, I don’t want to cheat. Think about it this way: It’s like you’re driving a Ferrari and one day you’re, like, I’m going to drive a punch bug. Like, why would you do that?”

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Then again…

“I may have some veggie chocolate muffins if I’m really going to allow a ‘cheat.’ To make them, I’ll juice and then collect all the pulp from the juicer. I’ll then use some gluten-free flour, put some vegan chocolate in the mix, chop some banana to put in there, and make it all into muffins. They’re amazing. So even when I’m ‘cheating,’ I’m still eating healthy.

And always have that one staple item to keep you grounded

I have the same exact breakfast shake every single morning. Out of 365 days, I probably have it 340 days. Every time I’ll use the same two sources of protein, Silk almond milk and raw milk protein, along with oatmeal, peanut butter, banana flaxseed, chia seed, hemp seed, beta alanine ice, and a little bit of water. And then I start my day.