An Australian personal trainer who deliberately packed on 88 pounds in six months so he could better understand his overweight clients' trials has learned personally just how difficult slimming down can be.
Paul "PJ" James had a sort of reverse New Year's resolution — to gain as much weight as he could and on July 1 he began the second half of his challenge — getting back into shape.
"The reason for doing it was to better understand and empathize with my personal training clients," said James, of Melbourne, Australia. "There's a lot of people who can't come into the gym for the first time because they feel embarrassed and they really appreciate someone […] to walk a mile in their shoes."
The once chiseled James, who used to sport picture-perfect abdominals and ripped muscles, now boasts a much more rotund figure. The 6'2" James has shed 10 pounds in six weeks and gained a greater compassion for those struggling to battle the bulge. The former underwear model has had to rethink his own training as he whittles down his waistline — starting out slow and struggling to see progress.
"I think I owe it to everyone to get my old body back," he said. "I just want people to see that it is possible to get back in shape."
For six months James didn't engage in any exercise and his diet was unrestricted.
"I decided to eat whatever I wanted," said James, whose journey is being chronicled for a documentary called "Fat and Back." "There were no restrictions."
Within in a few weeks, James began to feel a difference in his body. By the end of February the 32-year-old weighed 233 pounds and felt lethargic. His clothes no longer fit and he had begun wearing second-hand track pants.
James' blood pressure also had risen slightly.
As he continued gaining weight, James found it more difficult to walk and experienced muscle pain along with dangerous spikes in his cholesterol and sugar levels. "You're whole body changes. It's very difficult to deal with," James said. "My doctor advised me to slow down."
After months of eating nothing but fatty, fried foods and sugary drinks, James began liking his new diet — perhaps too much.
"I really enjoyed the food," he said. "But it soon became an addiction and I am currently fighting that addiction as well to sugar and fat."
James' first step to getting fit was to break his addiction, but he couldn't do it cold turkey. He gradually weaned himself off of sugar and fat. Today he believes he has kicked his habit.
Using fatty foods for fuel came with a price tag for James.
"I've actually been spending three or four times the amount that I would normally spend," he said. "People often think it's easier or it's convenient to buy just fast food, not cook at home so you save on time."
"It's actually a lot more expensive to be overweight than it is to be in shape," he added.
James was spending money to treat his rapidly emerging ailments. It's a symptom Americans also face as a study published in July by the journal Health Affairs estimates the annual health care cost for the average obese person is $1,400 higher than for someone who is not obese.
For James, weight gain resulted in more than monetary costs. The extra pounds also took an emotional toll; it was a price James underestimated.
"I felt hopeless," he said. "It is amazing how the mind plays an important part in this whole thing. You start to doubt your own ability."
Like so many of his clients who were trying to lose weight, James was upset about his appearance. At least one of his clients found the journey humbling and inspiring.
"When I initially started training with him he was full of ego, very energized and as he started to pile on the weight he became more lethargic," said gym client David Mega. "It definitely allows him to understand his clients better and it also allows people like me to see that anyone with any fitness level can actually let themselves go."
James now is five weeks into his program to reshape his body, armed with the new insight from the first six months of the year.
When James finally did make it back to the gym to begin an exercise regimen, he couldn't do what he used to do. He had so much extra weight on his ankles and knees that he couldn't run because he was afraid of injuring his joints and he was unable to do a set of sit-ups.
"I don't want to claim to totally understand what it's like to be overweight," James said. "But hopefully my journey encourages people out there to take their own journey."
ABC News' Sarah Netter contributed to this story.