Campus & Community

Building a better American diet:

5 min read

School of Public Health conference looks at science behind diet recommendations

David Ludwig says that a breakfast of a bagel with low-fat cream cheese is ‘metabolically indistinguishable from a bowl of sugar.’ (Harvard News Office/Rose Lincoln)

The American diet has gone astray, lured by fat-free grains, breads, and cereals that have led not to a leaner promised land but to a quagmire of flabby bodies and rising risk of diabetes, experts at the Harvard School of Public Health said Sept. 9.

The U.S. government should shoulder part of the blame for America’s bread-gobbling masses, since it promotes “ideal” dietary guidelines in its food pyramid icon, featuring a base built on carbohydrates such as breads, rice, and pasta, and a tiny peak with fats, oils, and sweets.

The only problem is that science shows that refined carbohydrates like those found in white bread, white rice, and pasta are little different metabolically from sweets. Further, it has long been known that some fats and oils, specifically the mono- and polyunsaturated fats found in olive oil and some nuts are beneficial to the heart and warrant a larger place in the American diet than represented by their place at the tip of the pyramid.

Helped along by supersized portions, soft drinks, and a lack of exercise, America’s unhealthy diet has led to such a rapid increase in obesity rates nationally, that Mississippi earned the dubious distinction in 2001 of becoming the first state with more than 25 percent of its adults considered obese.

The problem of fixing America’s diet and crafting a new food pyramid – the government’s redraft is due in 2004 – along the way was tackled at a School of Public Health conference, “The Healthier Food Guide Pyramid: From Science to Practice.” The Nutrition Departments at both the School and at Brigham and Women’s Hospital sponsored the conference.

In addition to reviewing the latest science about nutrition, the conference also featured a discussion on how best to apply that knowledge. Several speakers offered advice from their own experience feeding the public in schools and restaurants.

School of Public Health Dean Barry Bloom cited statistics that showed obesity increasing 120 percent among African-American and Hispanic children and 50 percent among white children between 1986 and 1998.

The estimated cost of that increase is as high as $110 billion from obesity-related illness and disease, Bloom said, with $60 billion in direct costs alone.

“The topic is of enormous importance,” Bloom said. “It’s about spending scarce resources, and how to keep people healthy and how to treat those who are sick.”

Speakers reviewed evidence that points to the body’s rapid breakdown of processed grains into a type of sugar called glucose. This shoots blood sugar upward and then drops it below the level from which it started. Studies have shown that low blood sugar can raise the body’s adrenaline levels.

“How would a 10-year-old boy feel in class after a bagel with low-fat cream cheese [for breakfast] with low blood sugar and adrenaline surging,” said David Ludwig, founder of Children’s Hospital’s obesity programs and an associate professor of pediatrics at Harvard Medical School. “The results can be a hormonal nightmare. These foods are metabolically indistinguishable from a bowl of sugar.”

Speakers presented the results of several studies that show a low-fat, high-carbohydrate diet doesn’t help lose weight or promote health. Instead, they said, studies show the Mediterranean diet, which has relatively high levels of fat, is among the best for preventing cardiovascular disease, and that diets that include moderate levels of protein and fat are more satisfying and more effective for weight loss.

Research has also indicated links between diet and various cancers, indicating that a diet high in fruits and vegetables will significantly lower the risk of lung, breast, and a variety of other cancers.

Putting science into practice has been a challenge over the years, the speakers agreed, but state Rep. Peter Koutoujian, house chair of the state legislature’s Joint Committee on Health Care, said public concern over obesity is building and presents an opportunity to take action.

What that action should be is another question. Alison Forrest, food service director of Brewster Pierce Memorial Elementary School in Huntington, Vt., said using local produce to create healthy meals that kids and teachers will eat is possible. She talked about incorporating fresh greens and other healthy foods that kids like, such as walnuts, salsa, dried cherries, and trail mix, into meals.

Forrest also said that food education should be part of the school curriculum.

“About 100 years ago, when refined foods became widely available and cheaper in industrialized countries, the stage was set for new health problems,” Forrest said. “We have to work on all levels, on all ages, so that teenagers will be making wise food choices and, when they’re ready, having healthy babies, who will be given real whole foods at home and then will eat them happily when they get to school.”