Dennis Rosenlof has special sauce coursing through his veins.

"My first meal of the day is always at about 10:30, when they open up the Big Macs," Rosenlof, 64, told ABC News.

The fast-food giant McDonald's can keep its Egg McMuffins, Filets-O-Fish and all the rest of it. Rosenlof said he isn't interested.

"I enjoy what I eat," he said. "It tastes good, so I order the same thing every day."

And for Rosenlof, that's a Big Mac meal. The electrical appliance salesman and Vietnam vet is apparently in great health, despite being a self-confessed Big Mac-aholic with a 30-year habit.

"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," he explained.

That is 10 Big Macs a week. Rosenlof estimates he's scarfed down more than 12,000 of the special sauce-covered burgers in a lifetime.

He eats almost nothing else, except on the day of rest.

"Sunday my wife cooks meals and we eat a family dinner, so it works out great," said Rosenlof.

But health professionals recognize the vital nutrients he is not getting.

"What's missing from his diet it seems are vitamins, minerals, fiber," said ABC News Nutrition and Wellness Editor Dave Zinczenko. "The good news is he's keeping his calories in check, 700 fewer calories than the average American man brings in."

He just eats them all in Big Macs.

"It has all the major food groups in it," Rosenlof said. "I'm not sure what's in the special sauce, but you put them all together and it makes a fantastic sandwich."