For more than 20 years researchers at Harvard and elsewhere have been looking at the long-term health effects of eating certain types of foods. These researchers now have a good idea what’s good for you and what’s not, and in what quantities. However, that information is not reflected in the “food pyramid” produced by the U.S. Department of Agriculture. The food pyramid is the government’s official pronouncement about what Americans should eat to stay healthy. But according to Walter Willett, chair of the Department of Nutrition at the Harvard School of Public Health, the government’s pyramid is built on “shaky scientific ground.” In a new book, Eat, Drink, and Be Healthy, Willett offers his own food pyramid, based on two decades of nutrition research. “The food pyramid is tremendously flawed,” Willett says. “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.”