(CNN) -- John Memmer said his light bulb moment occurred when he couldn't fit on an amusement park ride with his son.
The 39-year-old auto insurance underwriter from Bloomington, Illinois, was on a family outing at a theme park in Missouri and his son, Alex, desperately wanted him to share a seat next to him.
"The attendant tried to push and squeeze me into the seat, but to no avail. I was too big to fit," said Memmer. "So there I was with hundreds of people staring at me as all of this was going on, and then I heard my son start to cry as I had to climb off the ride," he said.
A stranger in line agreed to sit with his son, but at that moment, Memmer knew it was finally time to lose weight.
"All the shoulda, coulda, wouldas catalyzed into an intense desire to finally do something about it," he said.
Memmer had noticed before the trip to the amusement park that he would get winded walking up the stairs in his home and had trouble keeping up with his kids while they were playing. And this depressed him. But the incident at the theme park was the "straw that broke the camel's back."
He started his weight loss program during the summer of 2009 and eventually lost about 115 pounds over the course of a year. His initial weight was 300 pounds. Memmer said he kept his plan simple: eating less and consuming fewer calories.
"While I was losing the weight, hunger was always a factor," he said. "So to counter that, I worked in lots of fruits and vegetables, as they provide lots of nutrients and have a lot of fiber and bulk per serving -- it really helped to satisfy me when I was hungry."
Memmer rediscovered his love for soup during his weight loss campaign and has learned his local grocery store stocks a large variety of options to prevent him from getting bored. Although many soups contain a high amount of sodium, Memmer says "this does not weigh on his mind and a recent check with the doctor showed a clean bill of health."
It took some time to adjust to his new eating habits. Snacking became a rare event because he knew he was eating fewer calories and wanted to make each calorie count.
He didn't want to go on a crash diet, so instead he decreased his daily caloric intake so he'd shed about two pounds a week, which many dietitians consider safe.
Memmer changed his mind-set about food, too.
"I realized early on that I would just eat absent-mindedly, and all those calories have to go somewhere," he said. He now makes a conscious effort to be aware of what he's consuming and mostly selects nutritious foods to eat.
"I'm not on quite as strict a regimen as I was when I was losing my weight, but I've found a nice balance that has allowed me to maintain my current weight level and I don't feel deprived at all."
The main staples of his diet are vegetables, whole grains and lean meats, but nothing is forbidden.
"I may have a cookie here and there, or even a piece of pie, but I consider it a special treat instead of a daily food item."
Memmer does not think in terms of "going on a diet" when he eats, either.
"Dieting implies that you're making a temporary change, and what is essential is making a commitment to a different way of living," he noted. "Once you've made the mental leap over that hurdle, you've taken the hardest step."
In moments of weakness, Memmer reminds himself to try to stay focused on his goals -- and thinks of his family and how he wants to stay healthy for them.
Memmer does not consider himself an athlete and doesn't have a regular workout routine. But he has found ways to incorporate activity into his life. He'll use the stairs at work and parks his car farther away from his office than before his weight drop. Work in his garden keeps him active, too.
"If you want an upper body workout, I highly recommend wrestling with a gas-powered tiller on unbroken ground," he chuckled.
He enjoys taking walks and appreciates the fact he can get around without his knees hurting or back aching, which wasn't the case before he shed pounds.
Memmer says his weight loss has inspired those around him and sparked a lot of conversation around his workplace. In fact, some of his colleagues have started their own campaigns to lose weight and achieve a healthier lifestyle.
"Sometimes, all it takes is a spark, someone you can point to and say -- if he can do it, so can I," he said.
As for amusement park rides, Memmer has "upped his game" and recently spent a family vacation at Walt Disney World's theme parks in Orlando where he was able to comfortably get on any ride he wanted with his children.
"Space Mountain and Tower of Terror were my favorite rides."