WASHINGTON — Washington -- As the watchdog of America's diet, Michael Jacobson starts by guarding his own offices. In this run-of-the-mill warren of rooms, there are no Snickers, no Cheese Curls, nothing by Frito-Lay. M&M; breaks are strictly forbidden. And employees live dangerously to even sip a diet soft drink in front of the boss. Instead, he prefers the nutritionally balanced world before him now: the ruby-red apples atop desks, employees downing spring water to quench their thirst and framed photos of gooseberries gracing the walls. But while the Center for Science in the Public Interest may seem like the land of low-fat living, it's actually more a hotbed of food controversy these days. And executive director Michael Jacobson is its caustic, charismatic king. After releasing ground-breaking studies trumpeting the fat in Italian, Chinese and Mexican restaurant food -- and being labeled everything from "Ralph Nader of the Refrigerator" to "the great Ayatollah of the food industry" -- he's preparing to dish up more sound bites today when the center releases its research on seafood restaurants. Sitting in his office, having just finished a luncheon salad of lettuce, tomatoes, broccoli, chickpeas, black olives and canned beets, it's hard to imagine this wiry, intense man being the object of so much name-calling. "It's shameful," Mr. Jacobson, 51, says with a laugh. "The one I found most amusing was a headline in the San Francisco Examiner. It was something like: "Is Michael Jacobson America's biggest killjoy?" I just see it as sophomoric. I don't take any of it personally. . . . All we're doing is providing information that's never been available before." Food professionals believe the center does much more than that, though. "They've made it clear that . . . they're going to methodically attack every part of the restaurant industry," says Wendy Webster, spokeswoman for the National Restaurant Association, a Washington-based group with 150,000 members. This time, though, the organization is ready with a counterattack. Days ago, it prepared a five-page general "response" with a parody of Jack Sprat in which the Sprats, after listening to the center's advice, starve on beans and weed paste. Renowned cookbook author Julia Child says that while it's sensible to be warned about fat, Mr. Jacobson's work produces more anxiety than awareness. "It's poisoning people's pleasure," she says. "This sounds like the death knell of gastronomy. . . . People need to take an adult point of view. We know what we need to do: eat in moderation, small helpings, a great variety, weight-watching, moderate exercise and have fun." But with obesity on the rise and heart disease still the No. 1 killer in America, the center's work takes on greater importance -- and has been lauded by policymakers including FDA Commissioner David Kessler. At times, Mr. Jacobson has felt the public has blamed the messenger for the message. "Our studies on restaurants and popcorn have discomfited people," he says. "What happened is that people were happily eating their Chinese food thinking everything is fine. Now their tongue tells them 'Eat that food. It's delicious,' but their brain says, 'Don't eat it. Didn't you hear about the fat content?' And those people are blaming us for engendering that internal conflict. "You chalk it up as resistance, denial. People have ingrown habits. They want to stick with them. They don't want to have any information that should suggest they change. . . . But over time, people will change and restaurants will change." Those changes are already happening. After the center's study about movie-theater popcorn showed that a medium buttered popcorn at a typical theater had more artery-clogging fat than a bacon-and-egg breakfast, a Big Mac with fries and a steak dinner combined, just about every movie chain introduced low-fat alternatives to popcorn that was popped in fat-filled coconut oil. Using a blend of showmanship and science, he takes on popular targets such as popcorn, tacos and kung pao chicken and sums up his findings with clever one-liners (popcorn was called the "Godzilla" of snacks; fettuccine alfredo was "a heart attack on a plate") that make his message memorable. Finding fault As for the research itself, the center's nutritionist Jayne Hurley recommends the subject based on surveys of popular mid-priced meals. On average, the center picks three cities, three restaurants in each city and up to 15 dishes at each restaurant. The meals are shipped to a Washington lab where a composite of each meal is formed. Samples are then sent on to another lab where they're analyzed for fat, calories and sodium at a total cost per survey of $25,000. Ms. Webster of the National Restaurant Association faults the study for mixing samples, measuring portions that are sometimes larger than people eat and choosing items that aren't always representative of menus. Mr. Jacobson acknowledges that the studies aren't perfect, but they represent the best effort with the center's resources, he says. They also provide a gauge that people wouldn't have otherwise. "To some extent, restaurants are providing people what they want, but they're not telling people what they're getting," he says. "Restaurants don't give nutritional analyses and people unwittingly or ignorantly eat foods they wouldn't eat if they knew what was in them." Although he didn't initially plan to be a consumer advocate, he founded the center with a partner in 1971 after getting his Ph.D. in microbiology from the Massachusetts Institute of Technology and working briefly with Ralph Nader. "In the '70s, we were rowdier. We couldn't get into meetings in government . . . so we had to be demonstrators and use publicity gimmicks," he says. Making a point He once sent 170 rotten teeth to the Federal Trade Commission to protest sugary food commercials aimed at children and dressed as Tony the Tiger to make a similar point. Just last year, he turned up on the news with a hammer and 50-pound block of hydrogenated vegetable oil to make a point about fat and cholesterol. But he's had an impact. He was among those who pushed hard for the 1990 National Labeling and Education Act, which radically changed the way nutritional information is presented to the public and made nutritional labeling mandatory on virtually all processed foods. The center also has grown. A nonprofit, it now boasts revenues of more than $10 million, and subscriptions to its Nutrition Action Health Letter -- from which it gets most of its income -- now number around 675,000. In between planning to tour with a book he co-wrote called "What Are We Feeding Our Kids?" (he's also the co-author of "Fast-Food Guide"), Mr. Jacobson is lobbying for a president's council on diet and health, which would be parallel to the one on physical fitness. So far exercise star Richard Simmons has pledged support, he says. While all this leaves him little time to focus on his own diet, Mr. Jacobson, who is 5-foot-8 1/2 and 150 pounds, says he lives by his word. He and his wife Donna Lenhoff, a lawyer who happens to work in the same building, and their 2-year-old daughter Sonya, eat basically a healthy diet: whole grains, vegetables, fish, pasta with vegetables. In his younger days, he admits to certain vices: including deep-dish cheese pizza, fried chicken and pot roast. But now he's seen the error of his dietary ways. "It's not like I sneak off once a month and have four hamburgers," he says. "Occasionally we have some . . . fat-free frozen yogurt." 6( MICHAEL JACOBSON'S FIVE WORST FOODS 1. Hamburgers: "Hamburgers and whole milk are two of the biggest sources of saturated fat." 2. Whole milk 3. Sugar-containing soda: "An enormous waste of calories." Egg yolks: "I tell people just eat the whites. Make egg-white omelets because of the cholesterol." 5. Salad dressing: "It's the No. 1 source of fat for the average woman." & HIS FIVE BEST FOODS 1. Whole-wheat bread: "Bread is the staff of life . . . It has a wide variety of nutrients." Sweet potatoes: "They're delicious and loaded with beta carotene and vitamin C. Fresh spinach: "It's got lots of beta carotene and vitamin C; it's fat free and low in calories. 4. Cantaloupe: "It's got fiber and . . . is almost fat free." 5. Skim milk: "It's got lots of calcium and other vitamins and minerals."