Randy Voss grew up on a farm outside Peoria, Illinois. "I remember saying 'boy, I just am so tiny I wish I could gain some weight.'"
And then something changed when Randy turned 11.
"I was kind of a picky eater before, and after that there was nothing I didn't like." Randy remembers suddenly being hungry all the time. The pounds started to pile on. He told us, "I just gained weight every time I turned around."
As a teenager - Randy was 50 pounds overweight. As he got older, things got worse. In his mid 30's, Randy had a hard time keeping up his dairy farm in northwest Wisconsin. He weighed 345 pounds, and could barely walk.
"I knew in the back of my mind this is a losing battle. I'm gonna lose this. I can't win this battle."
And then Randy met a young scientist from India doing a fellowship at UW-Madison. Nikhil Dhurandhar was studying a virus he believed was making people fat.
"We call it hit and run phenomenon. It is possible it comes in, turns something off or something on."
Adenovirus 36, or AD-36, causes the body to produce more fat cells. The virus eventually leaves, but the damage is permanent. "Treatment may be like any other type of obesity. There's not a special treatment for obesity due to viral infection," Dhurandhar explained.
He tested Randy, who was positive for antibodies to AD-36, meaning at some point he was infected with the virus.
Randy calls the discovery "absolutely liberating." He finally had an explanation for the weight, which he still had to lose. There is no cure for obesity caused by a virus.
Down to 190 pounds at one point, he was climbing back up the scale in his late 50's. Randy decided to have a gastric procedure.
"I had a little more energy so I could exercise better," Randy told us. He was finally starting to feel normal.
He's now 165 pounds. Randy follows a strict exercise and eating regimen. "If I stopped that lifestyle, that weight is out there around the corner. It would be back."
Now 64, Randy can't believe he's still around to enjoy his grandchildren. "It was just such a miracle that I found out about it when I did."
Dhurandhar was the first to discover a virus that causes obesity. Today, 10 other viruses have been reported. It's hard to say how many in the U.S. are infected with AD-36. Only people in research studies are being screened.
There is no treatment for AD-36, so the focus is on preventing the infection by developing a childhood vaccine.