A 25-year-old Cosby man is now the first person with autism to hike all 900 miles of trails in the Great Smoky Mountains National Park.

Garan Moore's need to lose weight set him and his mom on countless treks through the mountains. In 2012, he weighed more than 300 pounds

"We went to Dollywood and couldn't get the seatbelt to fit on the ride, so we had to get off," said Garan's mom Theresa Moore. "And that was heart breaking, and just my ah-ha moment."

That's when the pair started taking walks near their house in Cosby. Soon the walks got longer, and deeper into the mountains.

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The Moores hiked almost every week since then, unless the weather was too bad or someone was sick.

Now, six years and 80 pounds later, Theresa and Garan have hiked 1723.4 miles together.

"We've got backpacks, hiking sticks and water bottles," Garan said.

"Him being autistic hasn't stopped us," Theresa said.

They just finished the final trail in the Great Smoky Mountains National Park on April 21.

They can now check all 900 miles of the park's trails off their list.

That's a task no man with autism has completed until now. It's something Garan's mother will always cherish.

"Memories, oh gosh the memories we have now," she said.

The weight loss paid off, too. The Moores have been back to Dollywood where Garan rode all the roller coasters at the park.

"It fit!" he said about the seatbelt. They both say it's all thanks to hiking.

"He's my hero, he is really my hero to just keep going," Theresa said.

Garan's not slowing down any time soon.

"It's too late to stop," he said. "I won't stop."

Theresa said their next goal is to hit 2,000 miles and work on getting Garan's weight down more.