Representation Gaps Undermine Nutrition Guidelines' Impact: Hollie Raynor, PhD, RD, LD

Despite decades of dietary guidelines, the US Healthy Eating Index has stubbornly hovered between average scores of 55 and 60 since 2005, a signal, according to Hollie Raynor, PhD, RD, LD, that the problem may not be the science itself but whether the science has truly been implemented or whether it was ever designed to reach the right people in the first place.

Raynor, a member of the 2025 Dietary Guidelines Advisory Committee (DGAC) and executive associate dean of research and operations at the University of Tennessee College of Education, Health, and Human Sciences, made that case during the panel discussion "From Evidence to the Plate: What the New Nutrition Guidelines Mean for Diabetes Care," held at the American Diabetes Association 2026 Scientific Sessions. Her argument was pointed: If the research base informing population-level guidelines doesn't reflect the population it aims to serve, those guidelines will always fall short in practice.

Central to her message was the push to recognize precision nutrition not just as a biomedical concept, but as a social one shaped by race, ethnicity, socioeconomic status, food insecurity, and lived experience. Across multiple bodies of evidence she and her team reviewed, they repeatedly encountered homogeneous study samples and inconsistent demographic reporting, with variables like household food insecurity largely absent from the literature unless they were the primary research question. The result is a cycle in which guidelines are built on an incomplete evidence base, applied to a diverse population they were never designed to represent, and then deemed ineffective when chronic disease rates fail to budge.

In an email interview with The American Journal of Managed Care^® (AJMC^®), Raynor expands on the panel discussion and its implications for researchers, clinicians, and the future of equitable nutrition science.

AJMC: The panel emphasized the importance of representation in nutrition research. How can a lack of diversity among study participants affect the applicability of dietary recommendations in clinical practice?

Raynor: The applicability of any guideline becomes limited in practice if the research base isn’t reflective of the US. Potentially, if the research base that informs a guideline is representative of the patients that a clinician sees, the recommendation may be applicable.

AJMC: As precision nutrition continues to gain attention, what role does greater representation across racial, ethnic, socioeconomic, and cultural groups play in advancing more personalized nutrition strategies?

Raynor: It helps! Having more representation in samples helps identify potential moderators that may influence the relationship between the independent and dependent variable and could be a “precision” variable.

AJMC: Many nutrition studies have historically enrolled relatively homogeneous populations. What gaps in the evidence base remain, and where should researchers focus their efforts moving forward?

Raynor: We found 2 issues in reviewing the research base. The first was a lack of reporting on the sample, so you may not be able to identify what the sample represents. This becomes even more important as we identify potential “moderators.” For example, many in the nutrition field think that food insecurity may influence outcomes, but we did not find a lot of reporting of this variable in the literature we reviewed. The second was the issue you described: homogeneous samples (when reporting did occur). Researchers should be purposeful in having nonhomogeneous samples in research. This may take additional recruitment efforts that would need to be budgeted and planned for.

AJMC: From a patient care perspective, how can clinicians balance population-level nutrition guidelines with the reality that individuals may respond differently to the same dietary intervention?

Raynor: A clinician should take guidelines—but use a patient-centered perspective regarding implementation. This would mean incorporating the patient’s values, perspectives, and responses into the shared decision-making model of medical care.

AJMC: Looking ahead, what changes in research design, recruitment, or community engagement do you believe are necessary to ensure nutrition science better reflects the diverse populations it aims to serve?

Raynor: Recruitment, as noted earlier, would take more purposeful effort. Working with community partners could be one option to help with this purposeful effort.