When Sam Walker was 28, he got the shock of his life.

He was diagnosed with Hodgkin’s lymphoma, a form of cancer that commonly strikes young people. The cause is unknown, but the cancer is treatable, especially when detected in its early stages.

After only six months of chemo and radiation therapy, the disease went into complete remission.

That’s when Walker says he came to the conclusion that if his body was going to take care of him, he had to take care of his body. So after taking some time to recover from treatment, he joined a gym, linked up with a trainer and set out to get in shape.

It was a new path for Walker, 31, who says he has battled with his weight since fourth grade. When he was young, he was involved in speech and drama, not sports. He spent most of his time in front of the TV or playing video games. When he got older, he tried just about every weight-loss trick there was – diets, potions and exercise – but it never worked.

At his largest, Walker weighed 260 pounds, which isn’t that much when you consider he’s 6-3, but he’d never been able to get trim and stay that way.

His brief battle with cancer, though, changed his outlook. His weight had nothing to do with his cancer, but he figured losing weight would help prevent diabetes, heart disease and other problems.

Working with a trainer, he learned secrets to diet, exercise and keeping weight off. Just last March, the guy who used to find ways to duck out of running in gym class decided to take up running.

Actually, running turned out to be the perfect activity for Walker, who describes himself as an obsessive-compulsive planner who likes to set goals and come up with detailed plans to achieve them. By September, after just six months or so, he was in good enough shape to run the Fort4Fitness half-marathon, finishing in 2 hours, 33 minutes, just three minutes off his goal.

Well, the running season is largely over for now, but Walker, now 80 pounds lighter at 180, has started thinking about next year, and he’s set a goal. Run 1,000 miles over the course of 2012 and actually hit the 1,000-mile mark while running the Chicago Marathon, which takes place Oct. 6.

The goal also sparked an idea. Why couldn’t he use his 1,000-mile goal as a fundraising activity of sorts to help fight childhood obesity?

He isn’t looking for sponsors or anything. As a runner, he’d buy his own gear and pay his own entry fees into the races. He’d just start a blog and set up his Facebook page to fish for donations that he could use to help fund anti-obesity programs.

But he’s run into a problem. Sure, there are national organizations that specialize in fighting childhood obesity, but he hasn’t been able to find any local programs with that specific focus.

Walker has set up a meeting with a hospital to talk about possibilities. He’s spoken to the department of health about local programs that might exist, but for now, he has no idea where to give the money he expects to raise.

He plans to start accepting donations Jan. 1, but, he said, “I’m not going to accept donations if I can’t say where they’re going.”

When you think about it, though, maybe this is exactly the way that programs get started.

One way or the other, though, Walker’s goal to cover 1,000 miles on foot remains.