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DENVER — Every day, Marilyn Cartwright laces up her shoes and sets out on the runs she loves so much.

“I’ve been running for a very long time,” she said.

Cartwright is 55-years-old and has finished countless marathons and races. You would think she was the pinnacle of health, but on the inside she just didn’t feel good.

“I’m so tired, my joints hurt, my head’s foggy, my stomach hurts,” she said.

Doctors couldn’t figure out the problem and told Cartwright she should simply stop running.

“To me that wasn’t an option, because that’s my enjoyment,” she said.

That’s when she met Laura Woodard, a registered dietician.

“With Marilyn, the first thing she said to me was, ‘I feel puffy, I just feel really puffy’,” Woodard said.

Hearing Cartwright’s symptoms, Woodard believed she was suffering from food sensitivities. They’re different from food allergies.

“While an allergy has more external symptoms, the food sensitivities are going to have more internal inflammation,” Woodard explained.

Woodard did a test on Cartwright called LEAP. It’s a panel of 150 food antigens including chemicals, pesticides, and additives.

The results come back in a report showing each item with a green, yellow, or red bar indicating just how sensitive a person is to a specific food.

Using these results, Cartwright started changing her diet. The results were incredible.

“Within two weeks, my thumbs didn’t hurt,” she said. “My joints quit hurting, I felt better.”

She and her husband have adapted to her new diet and she doesn’t miss a thing. Woodard said results like this are typical

“We’ve gotten used to not feeling good,” Woodard said. “We don’t really know what good feels like anymore.”

Now Cartwright is feeling better than she ever has and is running faster than ever before.

“I was like a whole new person. It literally changed my life.”

Woodard said the most common food sensitivities are ones we’ve heard of: gluten and dairy. Every person is different, but she said in all the time she’s been testing people using LEAP she hasn’t had one person come back with no sensitivities.