WASHINGTON -- Getting people to eat "sustainable diets" is a worthy goal, but more work must be done to better define what a sustainable diet is and to make it culturally acceptable, several experts said here.
The experts spoke Wednesday during a workshop on sustainable diets, food, and nutrition sponsored by the National Academies of Sciences, Engineering, and Medicine (NASEM).
In trying to define a "sustainable diet," several presenters referred to the definition coined at the FAO Biodiversity and Sustainable Diets Symposium: diets that are "protective and respectful for biodiversity and ecosystems, culturally acceptable, accessible, economically fair and affordable; nutritionally adequate, safe and healthy; while optimizing natural and human resources."
Efforts must be made to close the food gap and increase calories by 56% in order to "feed nearly 10 billion people in 2050 in a manner that advances development and well-being while reducing pressure on the environment," noted Janet Ranganathan, MSc, of the World Resources Institute here.
Previous initiatives to change diets have emphasized information, education, and abstinence, but they have had little impact, Ranganathan explained. Instead, she said, those who want to change the way people eat should consider these four strategies that have been proven successful:
- Evolving social norms: For instance, many people associate masculinity with meat -- as seen in the common image of a man using a grill -- but that is an association that could perhaps be lessened or changed over time.
- Minimizing disruption: If having more people drink soy milk is a goal, for example, have soy milk available in the refrigerator section because that's where people generally go to get their milk.
- Selling a compelling benefit: In one case, a brewer that wanted to get more people to drink its lower-calorie beer focused on the beer's addition of lime flavoring as a benefit, rather than its lower calories.
- Maximizing awareness: To get more people to buy a healthy food, place it at the end of the supermarket aisle or at the top of the menu -- places where it is more visible.
Language and framing are key factors in getting consumers to make healthier choices, Ranganathan said. She cited a study outlined in a JAMA Internal Medicine research letter last year which found that the amount consumed of a particular vegetable -- for example, corn -- varied depending on whether it was described as "corn" (basic), "rich buttery roasted sweet corn" (indulgent), "reduced-sodium corn" (healthy restrictive), or "vitamin-rich corn" (healthy positive).
"Labeling vegetables 'indulgently' resulted in 25% more people selecting the vegetable than in the 'basic' condition, 41% more people than in the 'healthy restrictive' condition, and 35% more people than in the 'healthy positive' condition," Ranganathan reported.
To make food choices more sustainable, one option might be making the "power dishes" on menus -- the ones people eat most often -- more environmentally friendly, Ranganathan suggested. For instance, with Americans consuming 10 billion burgers each year, offering burgers with 30% mushroom and 70% beef could reduce greenhouse gas emissions, conserve water, and reduce agricultural land demand, she said.
Sustainable diets also have implications for disease burden in America, according to David Tilman, PhD, of the University of Minnesota. That's because "eight of the top 12 risks to health are diet-related," he said
For example, following a vegetarian diet results in an average reduction of about 40% in the risk of type 2 diabetes, while following a pescatarian diet reduces the risk of cancer by 15% on average. People who follow a Mediterranean diet have an average risk reduction of 25% in coronary mortality and about 20% in all-cause mortality, Tillman said.
How can healthcare providers help patients achieve a sustainable diet? "Most people identify their healthcare provider with where they get their information -- or where they want to get their information," said Barbara Schneeman, PhD, of University of California Davis. "I think medical doctors are a key resource to emphasize the importance of nutrition, emphasize importance of being healthy, and diet plays a role."
However, while doctors can help patients learn to use nutrition labels and otherwise pay more attention to nutrition, sometimes it can be more effective to refer the patient to a dietitian for that information, she added. "There's a wonderful resource there."
In the coming months, the information from the forum will be available in a peer-reviewed publication from NASEM, noted workshop chair Sylvia Rowe.