In his new book, Eat, Drink, and Be Healthy, Walter Willett, chair of the Department of Nutrition, disassembles the US Department of Agriculture (USDA) Food Pyramid and replaces it with one based in part on years of research done at HSPH and the Harvard Medical School. Harvard Public Health NOW asked Willett why he thinks the official pyramid is wrong and what consumers can do:

What prompted you to write Eat, Drink, and Be Healthy?

"We now have more than 20 years of research looking at the long-term health consequences of diets. This work has been published in many scientific journals, but I wanted to gather the material together in one place that was accessible and understandable."

It also seems that you wanted to clarify conflicting information about nutrition for consumers.

"Yes. There’s lots of misinformation out there. The public has received messages that have not been borne out by research or did not deliver promised health benefits. For example, women have been told to drink milk to strengthen their bones and prevent osteoporosis, but long-term studies have not shown reduced risk of fractures with high dairy intake. Women can get calcium just as easily from supplements."

The USDA Food Pyramid has been around for nearly a decade. In the book, you write that it was based on "shaky scientific ground." What do you mean?

"The Food Pyramid is tremendously flawed. It says all fats are bad; all complex carbohydrates are good; all protein sources offer the same nutrition; and dairy should be eaten in high amounts. None of this is accurate."

Then why hasn’t the USDA Food Pyramid changed?

"The Food Pyramid is meant to be based on dietary guidelines released by the USDA every five years. The guidelines actually have changed a bit to include more current information, but the Food Pyramid has never been revised. Whether the USDA is capable of doing the revision without being influenced by meat and dairy lobbying groups remains to be seen."

So you ended up including a food pyramid of your own in the book that illustrates the recommendations you make based on current research?

"Yes."

What do you see as some of the biggest problems in a typical American’s diet today?

"The number-one problem is too many calories, whether from fat or carbohydrates, in relation to our level of physical activity.

"Trans fat is also a major problem. This kind of fat is found in many kinds of margarine and other foods, especially fast food, but it is actually worse for your arteries than lard. Americans, particularly teens, are eating large amounts of it in the form of fried, fast food. Trans fat developed from the notion that saturated fats are not good for you, so therefore, anything else must be better, and margarine was promoted.

"Trans fat not only increases levels of ‘bad’ cholesterol in the bloodstream, but it also decreases levels of ‘good’ cholesterol."

What are some of the other problems?

"A relatively new concern is glycemic load, which results from carbohydrates that increase blood sugar levels. The USDA Food Pyramid promotes eating complex carbohydrates without differentiating among them, but there are major differences between carbohydrates.

"For example, the body breaks down glucose in a potato more rapidly than pure sugar, spiking glucose levels in the blood and increasing the risk of diabetes."

What is a common mistake people make when they are trying to eat a healthier diet?

"Getting rid of all of the fat in their diets. The USDA has promoted the strategy, but it can be really dangerous. Not all fats are bad and, in fact, some should be required in any diet. Monounsaturated and polyunsaturated fats found in foods such as nuts, avocados, fish, olives, and most oils help lower ‘bad’ cholesterol levels without affecting ‘good’ cholesterol levels.

"People also tend to replace fat in their diets with foods high in sugar or refined carbohydrates. A lot of people think that a plain bagel with jam can be a healthy thing to eat in the morning, but actually that is one of the unhealthiest duos you can eat because it has a high glycemic load. You’d be better off with scrambled eggs cooked in corn oil or a whole-grain cereal."

What did you eat when you were growing up?

"I grew up in farm country in Michigan and had an all-American diet: lots of red meat and potatoes. As I got older and more involved in nutritional research, I couldn’t ignore the data that those foods are not the best kinds to eat."

What do you typically eat in any given day?

"For breakfast, I’ll usually have something like cooked whole grains with fruit. Lunch may be leftover grains from breakfast as part of a salad, with vegetables, and nuts. Dinner is usually salad or vegetables with tofu, chicken or fish. In the back of the book, Maureen Callahan has created recipes for healthy meals that are also interesting and enjoyable."

What about secret indulgences?

"Sometimes I’ll have some flavorful cheese or a bit of chocolate."

What would you recommend to people trying to lose weight?

"Focus on the quality of your diet and make sure you feel satisfied at the end of the day. You can eat good food in reasonable quantities and still lose weight. Stay away from refined carbohydrates and sugars and keep an eye on the calories, whether from fat or carbohydrates. Also, exercise is very important. You should develop a plan that you can maintain permanently."

Pick Your Pyramid: HSPH's Walter Willett has created a new food pyramid, top, based on decades of research. The current official USDA food pyramid is at the bottom.