Designing Nutrition Studies for Long COVID and Related Infection-Associated Chronic Illness: Qualitative Insights From a Patient-Reported Evaluation of Ketogenic Metabolic Therapy

Background: Long COVID affects over 400 million people worldwide and has no FDA-approved treatments. Patients often rely on self-directed strategies, making their lived experiences an essential, yet underutilized, source of evidence. Ketogenic metabolic therapy (KMT) has demonstrated mechanisms relevant to Long COVID, including improved mitochondrial energy production, reduced oxidative stress, and modulation of inflammation, but remains underexplored. Methods: , a 12-week virtual program integrating KMT with lifestyle components. Recruitment emails were sent to 194 participants; 41 completed the online REDCap survey. Quantitative data were summarized descriptively. Qualitative data were analyzed using conventional content analysis. Results: Participants (mean age 41; 90% female) reported diagnoses including postviral dysautonomia, myalgic encephalomyelitis/chronic fatigue syndrome, and Long COVID. Four themes emerged: program benefits, challenges, recommendations, and scientific considerations. Key insights included the value of multicomponent synergy, extended duration, and prioritization of functional outcomes. Conclusion: Findings suggest nutrition trials for infection-associated chronic illnesses, including Long COVID, should consider incorporating longer intervention periods, multicomponent design, patient-centered outcomes, lived-experience integration, and tailored supports to optimize feasibility and impact.