In just 15 months, this 441-pound man who couldn't fit in a theater seat lost 228 pounds and completed a full marathon.

The motivation to change came when the 31-year-old recognized that he didn't have the energy to play with his two young children.

Since that realization a little over a year ago, Rob Sparkes has changed his eating habits, taken up running during the pandemic, and he now weighs just 216 pounds.

"Before, I couldn't even walk up a flight of stairs without feeling out of breath," said Sparkes, a salesman from Weston-Super-Mare, in England.

Prior to his weight loss, Sparkes was eating a whopping 6,000 calories a day and led a completely sedentary lifestyle, saying, "The furthest I'd walk is from work down to the shop to get food.

He detailed his food intake on a typical day:

4 pieces of toast before work; a bacon roll, a Coke, and some chips mid-morning; half-pound burger and fries or massive sandwich and family-sized bag of potato chips for lunch; snack mid-afternoon with chips and chocolate from the vending machine; then start snacking on more chips the second he got home from work.

For dinner, he recalls, "I'd order takeaway, typically a massive pizza, and later on I'd watch television and eat popcorn."

"I'd also drink about two liters of Coke every day. I just couldn't stop. I got in a really bad rut."

His doctor was actually shocked that he didn't have any underlying health issues, but warned him that it was only a matter of time until he would develop diabetes and joint problems.

"I'd only just had my second child and I was worried I wouldn't be around for my children," he told SWNS.

So in September of 2019, he changed his diet and started trying to lose weight.

"I don't really snack at all anymore. I eat a lot of chicken and veggies."

After losing some weight, Sparkes turned his attention to his physical fitness.

In March of 2020, he started running using the Couch to 5K app and joined a running club. On December 20th he ran his first marathon.

"It was meant to be an official one, but they all got postponed due to Covid, so my running club did an unofficial one."

"I had my wife and kids there waiting for me at the end, and it felt amazing. I ran it in five hours and 24 minutes, but I ran the whole thing."

He has four marathons booked for 2021 and runs a half marathon on most weekends to stay in shape.

He also raised £1,280 for the Alzheimer Society by hiking the Yorkshire Three Peaks Challenge—a 25-mile hike up the 3 highest peaks in Yorkshire.

Sparkes says that his wife has played a big role in his success by being so supportive.

"She was worried when she saw me gaining weight, but there was no stress or strain with the marriage," he said. But, she "absolutely loves the weight loss."

Now that he's achieved his fitness goals and lost the weight, Sparkes is looking into reconstructive surgery to remove his excess skin.

After 2021 he also plans to begin training for his first ultramarathon, a 50-mile race that only the most hardcore runners ever attempt.

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