The Science of Nutrition
Reviewed by Toni Martin, MD
CONSUMER HEALTH INTERACTIVEEat Drink and Be Healthy: The Harvard Medical School Guide to Healthy Eating
By Walter C. Willett, MD
Simon and Schuster
352 pp $25 
There is always room for one more nutrition book, especially one with the Harvard University seal of approval. Walter C. Willett is doubly Harvard -- he's the Chair of the Department of Nutrition at the Harvard School of Public Health as well as a professor at Harvard Medical School. His contribution to the field, Eat, Drink and Be Healthy, is mainstream, evidence-based and research-focused. For those who share his belief that the scientific method works to bring us closer to an objective truth, this is an authoritative source. Many people dismiss scientific research about nutrition and health. They don't care whether there is any credible evidence to back up the claim that a person with type A blood should eat differently from a person with type O blood, for example. They care about whether a diet makes them feel good, helps to lose weight, or confirms their prejudices about "good" and "bad" food. Those who prefer to believe extrapolations from scant data will be impatient with Willett's considered approach. The rest of us celebrate it. A clear and cogent guide
In fact, the best section of Eat Drink and Be Healthy is Chapter 2, "What Can You Believe About Diet?" Because Willett is a researcher himself and one of the leaders of the Nurses Health Study and the Health Professions Follow-up Study, he has produced a clear and cogent guide to evaluating nutritional research. Not too long ago, such a chapter might have seemed a little heavy for a nutrition book aimed at the general public. Today people need better tools to sort through the flood of nutritional information and misinformation in print, on television, and on the Net. And remarkably, Willett manages to avoid sounding like a textbook, probably thanks to P.J. Skerett, "an experienced science writer" he acknowledges in the preface. Let’s take the issue of “good” and “bad” fats, for example. Over the past 20 years, our understanding of dietary fat has grown steadily more detailed, like a bedtime story embellished night after night. Willett devotes a chapter to the new findings about different kinds of fats. He discusses the benefits of Omega 3 (n3) fatty acids and the dangers of partially hydrogenated fats. Overall, he advocates a variant of the Mediterranean diet, a regimen with less meat, milk, and sugar in favor of lots of fruits and vegetables, whole grains rather than white flour bread and pasta, and more olive oil and canola oil, rather than butter. In other chapters, he argues that women have been oversold the benefits of calcium and soy. He also blames an increased consumption of refined flour and potatoes for the jump in obesity that has occurred in the United States despite a decline in dietary fat. Obesity epidemic
According to the Centers for Disease Control and Prevention, 66 percent of Americans are overweight, and in fact, the CDC has called for a comprehensive approach to the epidemic of obesity, including stepping up exercise programs for schoolchildren and discouraging their consumption of fast food -- a dual effort to get teen-agers to snack on carrot sticks instead of fries and a soda. Adults could also benefit from more exercise, CDC officials say, so why not redesign communities so that they encourage walking instead of driving to the local store? All of this is on top of the CDC's fundamental recommendations for better nutrition at school and at home. Willett's chapter on obesity reflects the impotence of the nutrition community in the face of this issue. Willett devotes many pages to convincing the reader that obesity has a negative impact on health. Then he acknowledges, "Over the last few decades, we've been learning that it is far easier to prevent weight gain than it is to lose excess pounds." He does emphasize the importance of exercise, although he does not cite the many studies that suggest that your level of fitness may be more important than absolute weight as a factor in overall health risk. Nor does he take the opportunity to consider public health rather than personal approaches to obesity. When Willett disagrees with the food pyramid developed by the Department of Agriculture, he mentions that "what's good for some agricultural interests isn't necessarily good for the people who eat their products." That's about all he has to say about nutrition politics. If obesity is an epidemic, as he claims, it might be time to consider restrictions on fast-food advertising aimed at children, similar to the restrictions on cigarette advertising, or public service advertisements to promote an active lifestyle. At the end of the book, Willett includes a week's worth of menus and healthy recipes developed by Maureen Callahan, a dietitian. These are somewhat awkward (who wants to visit the health food store to add a few tablespoons of oat groats and flaxseed to a whole wheat pizza crust?) but creative. My teen-age daughter liked the "Mango Energy Blitz" smoothie, despite the carrot juice, which she won't drink by itself. Willett says that the rhythm of nutrition research is like the cha-cha, two steps forward, one step back. That rhythm also describes the efforts of the average family to make healthier food choices. Eat, Drink and Be Healthy is a step forward. Mango Energy Blitz 1 teabag kiwi-pear green tea (such as Republic of Tea) or Earl Grey tea
1/2 cup boiling water
1 mango, peeled and chopped (about 1 cup)
1 banana, peeled and cut into sections
1 cup apricot nectar (such as R.W. Knudsen) chilled
1/2 cup carrot juice, chilled
1/8 tsp freshly grated nutmeg l. Steep the teabag in boiling water for 3 minutes or according to package directions. Remove the teabag and put the tea in the refrigerator to chill. 2. Combine the mango, banana, and chilled tea in a blender or food processor and process until smooth. Add the remaining ingredients and pulse to mix. Pour into chilled glasses and serve. Yield: 4 servings
Serving size: 1 cup
Calories: 98
Protein: 0.7 grams
Carbohydrate: 25.2 g
Fiber: 2 g
Sodium: 27 milligrams
Fat: 0.2 g General: 12 mg of caffeine per serving. Hefty dose of Vitamin A and beta carotene. More than 25 percent of recommended amount of vitamin C. -- Toni Martin, M.D., is a board-certified internist and geriatrician who has practiced in Oakland, California for 19 years. She is also a member of the clinical faculty at UCSF Medical School, and has written for Hippocrates magazine, among other publications.
Reviewed by Michael Potter, MD, an attending physician and associate clinical professor at the University of California, San Francisco. He is board-certified in family practice.
Our reviewers are members of Consumer Health Interactive's medical advisory board.
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Last updated August 25, 2009
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