It’s safe to say 64-year-old Dennis Rosenlof is a picky eater. For the past 30 years, the Vietnam veteran has frequented McDonald’s for his meals, but for not just any order. Only the infamous Big Mac satisfies Rosenlof’s appetite.

"My first meal of the day is always at about 10:30, when they open up the Big Macs," Rosenlof explained to ABC News. "I enjoy what I eat. It tastes good, so I order the same thing every day."

The electrical appliance salesman does make room on Sundays for his wife’s cooking, but the rest of the week is “two all-beef patties, special sauce, lettuce, cheese, pickles, onions on a sesame seed bun.” According to the self-proclaimed Big Mac-aholic’s estimates, Rosenlof has eaten over 12,000 Big Macs in his lifetime.

"Mondays I always eat a Big Mac, two on Tuesdays, one on Wednesdays, two on Thursdays, one or two on Fridays, and two every Saturday," Rosenlof told ABC News. "It has all the major food groups in it. I'm not sure what's in the special sauce, but you put them all together and it makes a fantastic sandwich."

Although Rosenlof claims that he is perfectly healthy, nutritionists and healthcare professionals don’t recommend his specialized diet. "What's missing from his diet it seems are vitamins, minerals, fiber," said Dave Zinczenko, ABC News nutrition and wellness editor. "The good news is he's keeping his calories in check, 700 fewer calories than the average American man brings in."