Finding common ground on nutrition advice

David Ludwig (left) speaks on a panel with Walter Willett during the Oldways Finding Common Ground conference.

November 30, 2015 — What is the healthiest and most sustainable way of eating? How can public health experts guide consumers amid a sea of often confusing nutrition advice? Researchers from Harvard T.H. Chan School of Public Health and other institutions grappled with these questions during a recent conference in Boston, Mass. on November 17 and 18. Hosted by Oldways, a non-profit focused on nutrition education, the Finding Common Ground conference asked these experts to reach a consensus on nutrition advice.

Walter Willett, Fredrick John Stare Professor of epidemiology and nutrition and chair of the Department of Nutrition at Harvard Chan School, opened the conference by saying that this is a critical time for public health experts to convey a clear message about what it means to eat well. Willett says that the field of nutrition has come a long way since the 1970s when the recommendations were focused on “who could shout the loudest.”

Now, Willett says that experts have much more data to work with. “We don’t have perfect information. We’ll never have perfect information. But, we do have lots of evidence. We need to take that and utilize all the information to put together the best diet recommendations.”

See a Q & A with Walter Willett on obesity trends from the November 30 edition of the Harvard Gazette.

During a presentation titled, “Which Comes First, Overeating or Obesity?—The Effects of Glycemic Index on Obesity,” David Ludwig, professor in the Department of Nutrition at Harvard Chan School, explained how new information has changed our perceptions of traditional dietary advice, such as “eat less, move more.” Not only is that information misguided, explained Ludwig, but it’s doomed to fail. That’s because our body weight is under biological control through a series of overlapping neurological, hormonal, and other signals in the body, he said.

Ludwig says the focus should be on diet quality, not quantity. For example, that could mean choosing low glycemic-load foods—such as fruits, legumes and whole kernel grains—over high glycemic-load carbohydrates (processed grains, potato products, and added sugar).

During the conference, experts, who represented a wide range of viewpoints, from paleo to vegan perspectives, released a consensus statement on healthy eating. Among the key points was that the these scientists  gave strong, collective support to the food-based recommendations of the 2015 Dietary Guidelines Advisory Committee, and to that committee’s endorsement of healthy food patterns such as the Mediterranean Diet, Vegetarian Diet, and Healthy American Diet.  Specifically, they agreed that a healthy dietary pattern is higher in vegetables, fruits, whole grains, low- or non-fat dairy, seafood, legumes, and nuts; moderate in alcohol (among adults); lower in red and processed meats; and low in sugar-sweetened foods and drinks and refined grains. The conference scientists also strongly agreed that environmental effects, such as impacts of red meat consumption on climate change, should also be considered when developing dietary guidelines because food security requires that a food supply be sustainable.*

Willett and David Katz chaired the scientific consensus committee. Other Harvard Chan School faculty presenting at the conference included Eric Rimm, Frank Hu, and Meir Stampfer.

Noah Leavitt

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Read the consensus statement from the Finding Common Ground conference

Carbohydrates and Blood Sugar (Nutrition Source)

Photo: Lew Harriman

*This story was updated on December 1, 2015