At 340 pounds, Dr. Brian Spar recalls sweating while bending down to examine a dog in his Long Island practice.

That was four years ago. Now weighing 185 pounds, the veterinarian-turned-fitness buff is basking in the media spotlight after being handpicked to inspire others to get healthy by slimming down with diet and exercise.

Last month, Spar, 32, was featured on The Today Show as the newest member of its Joy Fit Club. The segment, headed by nutritionist Joy Bauer, spotlights people who have lost and kept off 100 pounds or more.

Spar walked on set, all smiles while replaying his latest feat — completing the New York City Marathon.

“I just started (dieting and exercising) and it just snowballed,” he says, reflecting on how he gradually went from a 54-inch to a 32-inch waist size in pants.

“A flip just switched in my head,” Spar tells the VIN News Service. “I had been heavy all my life, even as a kid. But the weight gain started to get really bad when I went to vet school at the University of London. I did whatever I wanted there, eating fried foods and drinking lots of beer. I would have a half-can of Pringles every day.”

It wasn’t until Spar saw an unflattering photograph of himself on his father’s desk that he decided to lose weight.

“I was always the laziest, most unhealthy person ever. But when I saw that picture, it was a harsh realization. I was feeling old. I was always sweaty and achy. I had to change.”

Today, Pringles are banned from the Spar household, and the small-animal practitioner no longer frets about squeezing into airplane seats. Instead, he abides by a strict diet, exercises daily and pops Altoids when faced with a “temptation.”

“I’m petrified of going back to what I used to be like, so that’s what keeps me going,” Spar says. “I like not being the biggest guy in the room. My advice to anyone who wants to lose weight is that you have to decide within yourself to do it. It’s not easy, but it’s not as hard as you might think.

“I’m still kind of amazed that this body is actually me.”