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The U.S. government is heading toward advice on sustainable diets.

The U.S. government is heading toward advice on sustainable diets.


Greening the food pyramid

Advice about a healthy diet might soon take the planet itself into account. The next version of Dietary Guidelines for Americans, the major nutrition report from the government agencies that brought you the food pyramid, seems likely to contain advice about sustainable food choices. The prospect is already generating controversy.

Every 5 years, a new set of dietary advice comes from the U.S. Department of Agriculture (USDA) and the Department of Health and Human Services (HHS). It usually boils down to what your parents told you about eating a balanced diet. In 2010, the guidelines tried something new, switching from a food pyramid to a plate (and, for the first time, specifically urging Americans to eat more fish and less pizza). The changes are based on a review of recent research findings by outside scientists, whose recommendations are turned into guidelines by agency scientists and officials.

At an advisory panel meeting today, scientists discussed why it matters how the food you eat is produced. A subcommittee on food sustainability and safety, chaired by Miriam Nelson, a nutritionist at Tufts University in Medford, Massachusetts, presented its preliminary conclusions. "Promoting more sustainable diets will contribute to food security for present and future generations by conserving resources," the subcommittee found. "This approach should be encouraged across all food sectors."

In addition, sustainability could also encourage people to eat a diet richer in grains, fruits, and vegetables. "Research shows that, with young adults, a green message can be a real motivating factor," Nelson said at the meeting, which was webcast but not open to the public. "It could be used as another messaging tool."

The subcommittee reviewed the scientific literature, finding 15 peer-reviewed studies of dietary patterns, health, and environmental sustainability. These studies looked at how replacing meat and dairy with plant-based foods can have a positive impact on greenhouse gas emissions, energy, water, and biodiversity. All the studies showed that higher consumption of animal products inflicted more damage on the environment. "We're finding remarkable consistency here," Nelson said at the meeting.

It's not clear how detailed the sustainability advice will be. Nelson hinted that the subcommittee might stick to simply recommending a more plant-based diet and not go as far as preferring organic food. The subcommittee is reviewing the evidence on grass-fed versus corn-fed beef. It's also considering advice about the most sustainable way to increase fish consumption, with input from National Oceanic and Atmospheric Administration Fisheries.

Some conservative groups have objected to the inclusion of sustainability in the dietary guidelines. "Sustainable food systems and environmental protection may be important, but these issues don’t belong in discussions of healthy eating," wrote Jeff Stier of the National Center for Public Policy Research, a conservative think tank in Washington, D.C., in an op-ed in The Des Moines Register today.

Stier also objects to the recent appointment of Angela Tagtow to lead the USDA Center for Nutrition Policy and Promotion, which is responsible for USDA's involvement in the dietary guidelines. Tagtow, who began on 14 July, was a fellow at the Minnesota Institute for Sustainable Agriculture and then started Environmental Nutrition Solutions, a company that aims to establish sustainable food systems. "This isn’t nutrition," Stier wrote. "This is code language for politically charged activism."

Either way, it seems to be a sign that USDA is interested in including sustainability in its dietary guidelines.

The advisory committee is scheduled to hand its recommendations over to USDA and HHS this fall. The official guidelines will come out a year later. The United States would not be the first country to have federal advice on sustainable diet. Sweden, the United Kingdom, and the Netherlands issued recommendations between 2009 and 2011.