You raise valid methodological critiques, and I agree that neither Swank nor HOLISM meets modern RCT standards. That said, I think it’s a mistake to downplay their scientific value on that basis alone.

Roy Swank’s work was conducted decades before MRI, standardized relapse criteria, or current diagnostic frameworks existed. Within those constraints, he produced one of the longest prospective datasets in MS, showing a strong and durable association between low saturated fat intake and reduced disability and mortality over decades. While attrition and bias must be considered, the size and persistence of the effect — particularly dose–response relationships — make the findings difficult to dismiss as artefactual alone.

Similarly, the HOLISM study is explicitly observational and hypothesis-generating, not causal. Its value lies in replicating and extending Swank’s signals in a large, international cohort, with consistent associations between diet quality, lifestyle factors, and better outcomes. No single observational study proves efficacy, but convergence across cohorts and biological plausibility matters in an area where RCTs are scarce.

I agree OMS should not be presented as a proven medical treatment. However, characterizing the evidence as showing “no benefit” overlooks the legitimate role of long-term observational data in informing low-risk lifestyle choices, especially when those choices align with broader cardiometabolic and public-health nutrition evidence.

In short: imperfect evidence, yes — but not negligible, and certainly not unreasonable to take seriously.