"The American diet is out of whack," claims Jane Brody, 40, award-winning science and health writer for the New York Times. "Currently three out of five calories consumed by the average American come from fats and added sugars. That means that the minority of what we consume has to supply 100 percent of our essential nutrients. "As a result, we are plagued by such diet-related chronic diseases as hypertension and obesity and have become a nation in which most quick-weight-loss books, no matter how bizarre, sell like hotcakes. According to the Brooklyn-born Brody, however, people also hunger for scientifically sound information about nutrition and weight control. She provides it in her current best-seller, Jane Brody's Nutrition Book: A Lifetime Guide to Good Eating for Better Health and Weight Control (W.W. Norton & Company, $17.95). Married to playwright-lyricist Richard Engquist (who lost 26 pounds following Brody's advice) and the mother of 11-year-old twin sons, Erik and Lorin, Brody graduated with a B.S. from Cornell and in 1963 received her master's in journalism from the University of Wisconsin. A New York Times staffer since 1965, she still lives in Brooklyn. There Brody discussed America's eating habits, and the need to change them, with Bonnie Johnson of PEOPLE.

What is wrong with the American diet?

Evolution tells us that we are primarily a vegetarian species with occasional feasts of meat. That is the balance our bodies were designed to handle. But we have shifted that balance so that the majority of our foods are now from animals and the minority from plants.

What is the result of such a shift?

An enormous increase in consumption of fat and cholesterol, and a decrease in fiber and vitamins and minerals. The diseases that are killing vast numbers of us—heart disease, diabetes, high blood pressure—are all related to this diet.

What would be the ideal formula for a healthy diet?

I would say 65 percent of our diet should be from complex carbohydrates—starchy foods such as potatoes, rice, pasta, dried peas and beans, bread and other grains as well as vegetables and fruits. Some of these foods have mostly sugar as their carbohydrate, but it is natural sugar and it is packaged in fiber, vitamins, water and minerals. An apple may have as much sugar as a piece of candy, but with the apple comes good nutrition.

What about protein and fat?

Americans think protein is so important that the average person eats twice as much as he really needs. Protein should make up 10 to 15 percent of the diet and fat 20 to 25 percent.

Aren't you essentially advocating a vegetarian diet?

You don't have to be vegetarian at all. My family isn't. We still eat meat, chicken, fish, dairy products and eggs, but in small quantities. There's nothing wrong with meat per se. It's the amount that poses the problem. My husband was a meat-and-potatoes man when I met him, with the emphasis on the meat. He's still a meat-and-potatoes man, but the emphasis now is on the potatoes.

What are some of the other gross misconceptions about nutrition?

The biggest one is that we think of starchy foods as fattening and not particularly good for you. They are supposed to be deficient in nutrients. But that's untrue. Ounce for ounce, they are less fattening than our typical protein foods. A five-ounce steak has about 550 calories. A five-ounce baked potato has about 110, five ounces of rice 154. Yet what do people give up when they want to diet? They pass on the potatoes. They wouldn't think of having a spaghetti dinner with a meat-and-tomato sauce, and yet that has fewer calories than a steak dinner or even a tuna salad!

Is honey more beneficial than sugar?

Most people don't realize that honey is full of sugar. They metabolize exactly the same. In some ways honey may not be as good for you as white refined table sugar. Some honey contains a possible carcinogen that bees pick up from the plants they feed on, and honeys can contain botulism-causing spores that occur naturally. Plus honey may rot the teeth faster than sugar. The amount of nutrients in honey is too small to make it a significant source of nutrition. Sugar is sugar.

Are natural and health foods really more healthful?

Many poisonous substances in the world are totally natural. The toxin that causes botulism is natural. Poison ivy is natural. You don't eat things just because they are natural. Certain natural things are good for you. Whole grains and fruits and vegetables processed in your kitchen are better for you than things that are processed in a factory.

How is the average person supposed to decide about his diet when the data—for example, about caffeine and cholesterol—are conflicting?

I present both sides of the argument and then tell people where I think the best evidence lies. For example, caffeine, like all drugs, has unwanted side effects. But current evidence suggests the picture isn't as bleak as it may have seemed. There is no convincing evidence that moderate consumption increases the risk of heart disease, and the suggestion that coffee drinking increases the risk of bladder cancer has not stood the test of further research. The recent link of coffee drinking to cancer of the pancreas has been challenged and needs further study.

What about cholesterol?

There is a lot of evidence in both directions. I evaluated everything and made my recommendations to cut down on fats and cholesterol based on that. If a reader says, "But I don't believe that," fine. Then skip that chapter. From studies with animals, the evidence that saccharin is a carcinogen is rather convincing. Yet people want that noncaloric sweetener. They'd rather take the chance. However, you can cut down.

Doesn't cutting down characterize your entire approach to eating?

My theory of weight control is to eat normal foods and normal meals and not cut anything out of the diet. I used to weigh 35 pounds more than I do now. That's a third of my body weight. I'm thin by design. But I don't feel deprived, because I can have all those things I ate when I was fat. The difference is the amount, that's all.

Are any of the fad diets worthwhile?

No diet that distorts a basic nutritional balance by leaving out an entire food category makes any sense. The Atkins and Stillman diets and even the Scarsdale diet are high in fat and protein and very low in carbs. The Beverly Hills diet goes to the other extreme. There's practically no protein in the first three weeks of the diet. It's a plan for life that's a potential plan for death. Your body can't handle that kind of stress. You distort the nutrient requirements, knock out nerve and muscle function—and your heart is a muscle.

How about the Weight Watchers and Pritikin diets?

Weight Watchers is a lot more sensible, because you have leeway and it's a balance of the essential nutrients. Still, like all the diet schemes, it puts too much emphasis on protein. Nathan Pritikin is really right because he stresses complex carbohydrates. I'm not suggesting that anyone adopt this diet, because it's very rigid—there's little fat and no sugar allowed. For someone with heart disease or diabetes, these extremes may be tolerable and useful. But that's too extreme for most of us.

Does that mean an occasional Big Mac is okay?

Sure. A Whopper and a shake is my absolute favorite freakout. And we eat lots of pizza. It's a good food. It's main drawback is that it's high in salt, but the nutritional breakdown on pizza falls into the formula I've discussed—mostly carbs and relatively low in fats.

Is one time of year better than another to make changes in eating habits?

Summer is the perfect time to start on the road to more sensible and healthier eating. Fruits and vegetables are plentiful, and most people aren't as hungry in the summer, so it's easier for them to cut down. It's also a good time to start exercising—the best way to increase your metabolic rate. At my height and weight—5' tall, 100 pounds—I need 1,200 calories a day if I'm a sedentary female. But I'm an active female. I run or ride my bike every morning and swim four times a week. That allows me to eat 2,000 calories a day without gaining weight.

What do you think the result would be if society adopted your approach?

We would probably live into our 80s without being sickly and die from old age without being crippled by chronic diseases. Dr. Ernst Wynder, president of the American Health Foundation, once said, "The goal in life should be to die young as late in life as possible." That's what I envision.