In 1984 Americans will spend an estimated $41 billion on fast food. Michael Jacobson, right, a Ph.D. in microbiology and the founder and executive director of the Center for Science in the Public Interest (CSPI), believes much of this money will be ill-spent. An independent consumer-advocacy group supported by membership dues and foundation grants, CSPI collected nutritional data from fast-food companies and published its analysis of the information last summer in Nutrition Action, a magazine the group puts out 10 times a year for its 30,000 members. The 5'9" Jacobson, 40, who runs and bicycles regularly and weighs an exemplary 143 pounds, discussed CSPI's findings with correspondent Dolly Langdon in his one-bedroom co-op in Washington, D.C.

Why do you single out Wendy's triple cheeseburger as the worst fast food? You have even nicknamed it the "coronary bypass special."

Fast foods in general tend to be too high in fat, sodium and calories—and deficient in minerals, vitamins and dietary fiber. According to unpublished figures provided by the company itself, Wendy's triple cheeseburger with all the fixings has the highest fat content of any fast food we've seen. Of its 983 calories, 576 come from fat, and it's loaded with 1,280 milligrams of sodium. Doctors and nutritionists recommend that only a third or less of our calories come from fat and that we keep our daily level of sodium somewhere between 1,100 and 3,300 milligrams.

Are the other four on your "worst five" list—Extra Crispy dark meat Kentucky Fried Chicken dinner, Burger King Whopper, Pizza Hut Super Supreme pizza and McDonald's Filet-O-Fish Sandwich—just as full of hidden horrors?

Although Wendy's triple cheeseburger is significantly the worst, the others aren't ranked in any particular order. They were chosen to exemplify several problems, most of which come down to fat, sodium and calories. And we selected different brand names because we didn't want to pick on any particular chain, although we could have. Burger King french fries, for example, have twice as much sodium as McDonald's french fries. The actual amount depends on the kid who is pouring on the salt. But I did see a notice Burger King sent around to its restaurants saying, "Add more salt" to the french fries.

Why did you pick on chicken for your "five worst" list? Most diet doctors suggest it is a nutritious food.

You're right. Chicken is a low-fat food. But the Extra Crispy dark meat Kentucky Fried Chicken dinner converts a lean food into a high-fat meal, and that's unfortunate. Sixty-three percent of the calories in this dinner of chicken, mashed potatoes, gravy, coleslaw and biscuit come from fat. It also is higher in fat than the standard Kentucky Fried Chicken dinner, which is about 50 percent fat. So they might have called it "extra greasy." It's also high in sodium: 1,480 milligrams.

We were also amazed to find a fish dish on your list.

You were supposed to be. If you went into a regular restaurant and ordered broiled or baked filet of fish, most doctors would pat you on the back. Fish is very nutritious. It's high in protein and very lean in general. But if you order a fast-food restaurant's fried filet of fish, you get approximately 50 percent fat. For example, McDonald's fish sandwich contains two and a half times as much fat as an ordinary McDonald's hamburger.

And what's wrong with a Burger King Whopper?

The trouble with specialty burgers—you could put the Big Mac in this group—are the special sauces used to make the sandwiches unique. The Whopper's sauce is pure mayonnaise, which just adds fat to the fat already in the meat. The total fat in a Whopper is 342 calories out of 670, more than half the fat somebody on a 2,000-calorie diet should eat in a day. Also, enough pickles, ketchup and salt are added to the sauce to make its sodium total 983 milligrams. And if you have the cheese, you get 1,260 milligrams.

Suppose you skip the sauce. Then wouldn't you be getting a healthy dose of beef protein?

Most people buy hamburger for the protein. But one of the shockers we found was that Wendy's single hamburgers and cheeseburgers both have more fat in them than protein. That little lady in the "Where's the beef?" commercial might move over to a Wendy's hamburger stand and say, "Where's the protein?" Wendy's hamburgers were the only products we found that had more fat than protein.

Now what's the bad news about Super Supreme pizza?

The extras, like pepperoni or other sausage-type products in the Pizza Hut Supreme, hike the fat content by 62 percent and the sodium content by 50 percent over the regular Pan pizza. Every serving, which is two slices, also contains extra calories—710, compared to 580.

Why do you direct your studies toward specific brand names instead of just making general suggestions to people about ways to improve their diet?

We try to mention brand names as much as possible because people relate to brand names. They don't go to a fast-food restaurant; they go to a Wendy's or a Kentucky Fried Chicken or a Roy Rogers. One of the reasons we compiled this report is that some of the fast-food chains, McDonald's in particular, have been trumpeting the nutritional value of their products. They fail to mention that their foods are high in fat, calories and sodium.

What positive things can you say about fast foods?

Fast foods do provide more vitamins and minerals in their calories than do junk foods—like soda pops and candy bars—which are basically empty calories. If you have a hamburger, you do get some iron and protein, for example. Although you're not getting as many vitamins and minerals from the amount of calories you consume in an Egg McMuffin breakfast as you would from a meal of fresh fruits and whole-grain bread or cereal, you're still a step above a junk breakfast of doughnuts and coffee. And some chains are beginning to introduce salad bars, baked potatoes and skim milk. I'm sure there are millions of Americans who were first exposed to a salad in a fast-food-restaurant salad bar, and that's good.

What would you put on your list of the best fast foods?

The only widely available main dish I could single out would be Wendy's chili. It does have a shameful amount of sodium—1,070 milligrams in a nine-ounce serving. But it totals only 260 calories, and only 72 of those are from fat. And the beans provide some healthy dietary fiber.

For those of us who will continue to frequent fast-food restaurants, how can we minimize the damage?

There are some foods very high in fat that I would just avoid altogether, like breakfast sausage. It's common to find fast-food sausage with twice as much fat as protein. It's one of those foods that promotes heart disease. Try to skip the butter on McDonald's English muffin and the sauces on the Big Mac and the Whopper. You don't have to eat the deep-fried Chicken McNuggets. Remember that anything fried is high in fat. Have fruit juice instead of soda pop, and head for the salad bar, if you can find one.

Now be honest. Don't you ever have a Big Mac attack or crave a double-thick chocolate shake?

Back in the '60s when I was in graduate school, I never had a thought about nutrition. I just ate what was served—Twinkies, bologna sandwiches with white bread and plenty of hamburgers at fast-food restaurants. And I felt fine.

But when I started doing research on food contents, I began to see the connections between what you eat and your arteries clogging up. Now my standby basic meal is sautéed vegetables on a bed of brown rice. My favorite snack is a baked sweet potato. I carry it around and eat it like an ice-cream cone. I do sometimes drink a milkshake, maybe twice a year.