Dennis Rosinlof, 64, told local television station KSL that he estimates he's eaten more than 12,000 of the signature sandwiches.
He also frequents the restaurant for dinner, sometimes consuming two sandwiches with fries in a day.
The 64-year-old is over six feet tall and a healthy 165 pounds, according to KSL.
His wife, a registered nurse, encourages him to eat healthier, but told KSL she isn't too concerned because his weight and cholesterol are at healthy levels.
A Big Mac meal at McDonald's has 930 calories, so even if Rosinlof eats two in a day, he's still clocking in at under 2,000 calories for his daily indulgence.