Kelly Gneiting, a hospital statistician and sumo wrestler from Arizona, will secure the official globe report if he completes the Los Angeles marathon in California on Sunday.
Mr Gneiting, 40, said he needed to run the 26-mile race as an inspiration to "people who are overweight, have lower self-esteem and feel they can't obtain things".
"I have superior self-esteem and believe I can do something," he advised the Daily Telegraph. "I'm major, but I really feel like I have a talent for this." Mr Gneiting, who is initially from Idaho, is 6ft tall and has a 5ft waist. He can be a three-time American sumo champion and has represented the US in the world championships.
He said that his size produced running uncomfortable. "It's challenging on my feet, my thighs and underneath my armpits," he said. He strategies to put on slick black Lycra leggings to avoid friction.
Mr Gneiting took up wrestling as being a youthful man of typical dimension, but began to acquire weight. "Food is really a little bit of a weakness," he mentioned.
After exceeding the 265-pound limit for typical wrestlers, he started sumo.
He finished the LA marathon in 2008 but was not in contact with the Guinness Planet File authorities. They stipulate that he should be filmed for that entire race and weighed before and immediately after.
The present report for the heaviest marathon runner is simply underneath 20 stone.
Mr Gneiting, who last time took 11 hrs, 45 minutes, is aiming to finish in less than 9 hrs.
"I'm likely to run as fast as I can," he said. "So I can present all my critics".
Kelly Gneiting World Heaviest Sumo Ever World Record 2011 Video
