In a statement released Friday, Subway said the complaint submitted to its website in 2011 expressed "concerns" about Fogle.
Fogle last month agreed to plead guilty to child pornography charges and to crossing state lines to pay for sex with minors.
"Since 2011, the company has strengthened its processes for reviewing and escalating customer comments, complaints and inquiries," Subway said.
Fogle, who lost 245 pounds by eating nothing but Subway for a year, gave the sandwich shop the image of being a purveyor of healthy options.
While Fogle didn't single-handedly turn Subway into what it is today, his story certainly helped the chain's image and popularity.