OAK BROOK, ILL. -- Michael Goldblatt probably would have fallen out of the family station wagon if anyone had told him that he'd get paid to eat McDonald's hamburgers when he grew up. As a boy, he'd gobble up burgers six at a time in the back seat, encouraged by one of those mothers who thought world starvation would somehow be solved if her son ate more.

Goldblatt's voracious appetite hasn't changed much -- he can still wolf down three Big Macs for lunch -- but now the 37-year-old is in the driver's seat at McDonald's. He's director of nutrition and product development for the world's largest fast-food chain.

"McDonald's has a nutritionist?" That's what Goldblatt says customers ask when he introduces himself at McDonald's restaurants. His reply: "Absolutely!"

While the job title may sound a bit oxymoronic, Goldblatt may be one of the most influential nutritionists the world has ever known, as Forbes magazine wrote in 1988. He may, in fact, be the most.

Nobody feeds more people more often than McDonald's. Worldwide, 250 people in 52 countries pass under the golden arches every second. That's 22 million people a day.

As Goldblatt himself says, "I can't think of anybody else in the world who enjoys the kind of latitude to make meaningful, substantive changes in the way Americans and the world eats."

Nevertheless, the choices McDonald's and other fast food companies are making these days are coming under increasing scrutiny. In April, McDonald's was lambasted in full-page newspaper ads by Nebraska millionaire Phil Sokolof for "poisoning America" with its hamburgers.

At the same time, during a period of slow growth, fast food restaurants are turning to nutrition as a way to compete. Just a few weeks ago, Hardees announced that it was rolling out The Lean 1, which it claims is the lowest-fat quarter-pound hamburger offered by any national fast-food chain. The week before that, McDonald's announced it would begin posting nutrition information on posters and tray liners in all of its 8,200 U.S. outlets by the end of July.

Meanwhile, here at Hamburger University, McDonald's corporate offices and training center on the outskirts of Chicago, chef Rene' Arend has prepared a tasting of new products: pizza, grilled chicken sandwiches, low-fat milkshakes, low-fat frozen yogurt and orange sorbet. Goldblatt comes up with the ideas, Arend comes up with the recipes.

A jolly man from Luxembourg with a thick accent and a tall chef's toque, Arend looks like he belongs in the dank kitchen of a grand old European hotel, not the sleek, antiseptic headquarters of McWorld. Indeed, not surprisingly, the stamp of McDonald's is everywhere; the hallways of the corporate offices have names like French Fry Lane and West McNugget Row, and the campus bus is called the McShuttle.

Inside the glass-enclosed test kitchen, over slices of McDonald's test market pizza, Goldblatt explains how he formulated the product with nutrition in mind. At first, the pizza was rolled out with whole milk mozzarella because taste panels overwhelmingly preferred it. After the flavor and texture were perfected, part-skim mozzarella was substituted. The sausage chosen for the topping is a lower-fat version.

During the round of grilled chicken sandwiches, Goldblatt explains some of the considerations being made with the test market product. Would people like more tomatoes? What kind of dressing? Do we want a whole breast? Is it the right size? Shape?

In his capacity as director of both nutrition and product development, Goldblatt says he has learned that "you cannot sell nutritious food if it doesn't taste good." He can do anything he wants to the menu except change the taste of existing products.

Take, for example, the milkshakes. A few years ago, he attempted a reformulation. "We took out the fat and we didn't match the flavor," he says. They were rejected by management. So he went back to the drawing board and reformulated again. McDonald's introduced low-fat milkshakes nationwide last month.

Goldblatt says McDonald's has been trying for years with "absolutely zippo success" to replace the mixture of vegetable oil and beef tallow it uses to fry its french fries with all-vegetable oil. With some changes in processing, coordinated under Goldblatt's direction, the chain is currently testing french fries in 100-percent vegetable oil in 500 restaurants. The jury is still out.

What all this means is that it is far easier for Goldblatt to create new products than to change or replace existing ones.

The only way, for example, that he could ever take a Big Mac off the menu is if he developed something more popular. "A Big Mac is on McDonald's menu because it is a tremendously successful product," he says. "People love it. People want it."

In recent months, McDonald's has introduced nationwide non-fat apple bran muffins (made by Entenmann's), low-fat frozen yogurt, orange sorbet ("one of the attempts to put fruit on the menu," he says seriously), and is test marketing pasta salads, entrees and carrot and celery sticks. Goldblatt notes, however, that McDonald's is exploring the serving of fresh fruit, but is trying to overcome the problem of inconsistent quality.

With the test marketing of lasagna and fettuccine with clam sauce, McDonald's is attempting to gain in dinner market share, the fast food restaurant's most sluggish mealtime. "We own breakfast and we own lunch," Goldblatt says. "And it's my intent that we will own dinner."

Not only can it take McDonald's a long time to get a reformulated or new product to its taste specifications, but the distribution and supply system has to be in place before a product can go nationwide. McDonald's shopping list is so enormous that any changes or additions to its menu can cause massive shifts in the food supply.

The chain is one of the largest buyers of dairy and beef products in the United States and uses 2 million pounds of potatoes every day and 3,400 tons of sesame seeds a year for its Big Mac buns. With McDonald's low-fat milkshakes going nationwide now, Goldblatt predicts butter prices will fall noticeably because of all the butterfat back on the market. If the chain were to suddenly introduce its grilled chicken sandwich nationwide, there would be a substantial rise in the price of chicken, he said, so McDonald's has been working ahead with independent contractors.

Goldblatt says he originally wanted to introduce a "dynamite" raspberry sorbet, but there aren't enough raspberries in the world to supply him. Similarly, "We had only a third of the domestic stores on shrimp salad," he says, and the item had to be discontinued. McDonald's couldn't buy enough shrimp.

If director of nutrition and product development of McDonald's sounds like an odd combination, so too are Goldblatt's impressive and extensive educational credentials. He studied biochemistry and ancient Greek and Roman history as an undergraduate, has a master's degree in food science technology, a doctorate in nutrition and a law degree.

While teaching food and drug law at the University of California at Davis, he was tapped by General Foods. The company "basically said, 'you have a fascinating background, really interesting, but you need to be educated in the world of business,' " as Goldblatt recalls. So General Foods hired him as director of consumer nutrition affairs and paid him to learn about the corporate food world.

Then, after what he understands was "an extensive search that lasted for almost a year," he was hired by McDonald's in 1986. While the fast food giant had employed nutrition consultants before, this was the first time the position was elevated to such a high level in the corporation, Goldblatt says.

When he first got the job, his peers in the science and nutrition communities asked him how, in good conscience, he could work for McDonald's. Goldblatt dismissed it as one of "the most ignorant" questions. "How could you refuse the challenge?" he asks.

Kristin McNutt, president of Consumer Choices, Inc., and former associate director of the Good Housekeeping Institute and vice president for consumer and scientific affairs at Kraft, who has known Goldblatt for more than 10 years, calls him a risk taker. "You wouldn't work for McDonald's if you weren't. Anybody in the field of nutrition with credentials like Michael's has to live with their colleagues raising an eyebrow."

Nevertheless, Goldblatt seems to enjoy the controversy, although he considers himself "provocative maybe," not controversial. Donna Porter, a nutrition policy analyst in Washington and a longtime personal friend of Goldblatt's, remembers when he gave the keynote speech at the Society for Nutrition Education's convention a few years back. It turned into a "wild" debate between Goldblatt and some members of the audience, she recalls, but Goldblatt didn't shirk the attacks. "He's very willing to stand up there, take the heat and shovel it back," she says.

"I am sure Michael comes across to a lot of people as being very arrogant and obnoxious," says Porter. But she thinks that impression is erroneous; he is simply a self-confident and competent scientist, she says. "He knows his stuff."

McNutt doesn't see Goldblatt as a "big ego person. I think he can give that impression because he is so bold and strong, but my sense is that he doesn't have an inflated image of his own importance. He's got street smarts."

With the intensity of a child genius and the inability at times to translate science into plain English, he might have been a techno-nerd if he weren't so talkative and good-humored. In graduate school, he used lobsters instead of rats for his nutrition experiments, in part because he wanted to "have fun."

His penchant for the offbeat sounds like it might have come from his father, who built an island off the coast of Florida, where Goldblatt grew up. The family later moved to a ranch in California.

His father was a test pilot, an engineer, an inventor and a tinkerer who in 1960 contracted with the city of San Jose to buy all its garbage. He then built a recycling facility and segregated out all the metals, the glass and the cardboard. "Then the bottom fell out of the copper market," says Goldblatt, and that was the end of the recycling project.

As a child and adult, Goldblatt has been blessed with a rocket metabolism. He says he usually consumes between 3,500 and 3,800 calories a day, and doesn't gain weight.

When he was little, one of his favorite dishes was a bread sandwich; he'd eat a whole loaf of cinnamon raisin in a day. It was this kind of habit that led his little sister one night at the dinner table to start crying spontaneously. "She was gaining weight watching me eat," he says.

A wrestler on his high school team, Goldblatt had to eat to keep up with his weight class, rather than starve and sweat like his teammates. Now, at a full-grown 5 feet, 8 inches, he weighs more than he ever has -- and that's only 134 pounds.

Because his job understandably requires a great many taste tests, his daily eating habits vary dramatically. On the day prior to this interview, however, before lunch he had polished off cereal and juice, four chicken sandwiches (to test the buns and condiments) and a couple of slices of pizza (to test some lower-fat cheeses).

And for lunch? "There was chicken, pizza, there was the sorbet, there was something else ... oh, the Big Macs. I probably had two or three Big Macs."

For dinner, which his wife usually cooks (she's a Cordon Bleu graduate chef), he had tortellini and ravioli, and strawberries and whipped cream for dessert.

He says his diet is "nutritionally balanced over time" and that he exercises daily. His cholesterol is 190 mg/dl, below the recommended 200.

As for the eating habits of others, he believes that people tend toward what he calls "motivated ignorance" when it comes to good nutrition. "They know what to do but they don't do it."

As for what they do when they go out to eat, Goldblatt believes that people treat food away from home "as an indulgence." He says he doesn't know where nutrition fits in among the list of reasons people eat at McDonald's.

"I think it's a complex melee. Most assuredly convenience, most assuredly taste. The quality and operation of the store. The cleanliness of the bathrooms. Bathrooms are an incredibly important issue to people. Are our bathrooms consistently clean as we always promise they will be?"

Goldblatt says his biggest frustration is "the cheap shots" people take at McDonald's without understanding its contributions. He truly believes in McDonald's commitment to good nutrition, he says, and that the corporation has reached a happy medium between public health and profitability.

Nutritional improvements at McDonald's have been subtle, he says, and it doesn't make a big fanfare about them. For example, the fast food chain added calcium to its burger buns, removed the chicken skin from its Chicken McNuggets, switched from fried to baked pies and reduced the sodium in its pickles, hot cakes and breakfast sausages by 30 percent. Chef Arend is also tinkering with reduced-fat mayonnaise, tartar sauce and Big Mac sauce.

"Because we are so much in the public eye, we are held to a standard that nobody else in the world is held to," says Goldblatt. There are times when you'd like to say to the world: 'Well, I mean, did you ever look at what the rest of the world is offering you?' "

He believes that if people looked at the rest of their diets, they would understand and appreciate how nutritious McDonald's food really is.

McDonald's is a company, where authority and power go to those who seize it, says Goldblatt. Does he seize it?

He hesitates, then jokingly asks that the tape recorder be turned off. "I'd like to think I have more power than I probably do. But I think it's fair to say that nobody has ever stopped me."