The Term ‘Plant-Based’ Diet Is Ambiguous Among U.S. Adults; Its Interpretation Differs Significantly Between Older and Younger Adults, New Study Finds

Washington, D.C. — When referring to diet, the term “plant-based” has mixed interpretations among U.S. adults, and its meaning varies significantly among demographic groups, according to new research published in the American Journal of Lifestyle Medicine. 

“The term plant-based has become popular in recent years and its meaning has never been clearly defined,” explained Dr. Anna Herby, nutrition education specialist at the Physicians Committee for Responsible Medicine and co-author of the study. “The greatest benefits of a plant-based diet stem from completely avoiding animal products. As dietitians who promote this healthful dietary pattern, we wanted to understand how people interpret the terminology in order to more clearly communicate about it.”

Key findings of the study include:

• 56% said “plant-based” means vegan—avoiding all animal products.
• 35% said it means eating abundant plant foods while still eating some meat, dairy and eggs.
• 7% said they didn't know.
• 2% gave another answer.

Interpretation also varied significantly by demographic group: 63% of adults ages 65-94 equated plant-based with vegan, compared with 51% of 18-to-34-year-olds.

The study analysis drew on the results of a survey of 2,202 U.S. adults conducted in July 2025 that was designed and executed by Morning Consult following the Best Practices for Survey Research of the American Association of Public Opinion Research.

“Defining ‘plant-based’ as excluding all animal products could make it easier for consumers to make confident decisions about food products by knowing that the term means there are no animal products,” said study co-author Shannon Menhardt, MS, a registered dietitian with the Barnard Medical Center. “A consistent definition could also make research findings and dietary recommendations easier to interpret and help provide clearer messaging for health professionals, patients, and the media.”