Results from the WAVES randomized clinical trial, which investigated the effects of the Swank and Wahls diets on individuals with relapsing-remitting multiple sclerosis (RRMS), indicated that fatigue improved from baseline after 12 weeks.

Measurements using the Fatigue Severity Scale (FSS) changed -0.94 ± 0.18 for the Swank diet and -0.71 ± 0.24 for the Wahls diet. Measurements using the Modified Fatigue Impact Scale (MFIS) changed -9.87 ± 1.93 for Swank and -14.41 ± 2.22 for Wahls.

Additionally, after 12 weeks, measurements for physical quality of life using the MS Quality of Life-54 (MSQoL-54) improved by 6.04 ± 2.18 for Swank and 14.5 ± 2.63 for Wahls. Mental quality of life scores using the MSQoL-54 did not show improvements on the Swank diet. However, these scores did improve on the Wahls diet by 11.3 ± 2.79. After 24 weeks, individuals maintained or improved fatigue and their quality of life and other outcomes.

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Lastly, researchers monitored patient adherence to the specified diet by collecting weighed food records for 3 consecutive days a week prior to these 4 study visits. At 12 and 24 weeks, patient adherence to the Swank diet was 86.8% and 81.1%, respectively, and the Wahls diet was 79.5% and 74.3%, respectively.

The authors state that “modulation of inflammation or oxidative stress” may explain the outcomes of this study, as both the Swank and Wahls diets “are rich in fiber and plant-derived phytochemicals that are known to be beneficial to the gut microbiota and modulate neuroinflammation.”

Regarding future study directions, the authors suggest that “results from this study provide justification for future randomized controlled trials with larger sample sizes and longer duration to evaluate changes in brain MRI-evaluated disease activity and exploration of underlying mechanisms by which diet may affect the MS disease course.”

Study Methods

The researchers at the University of Iowa Prevention Intervention Center in Iowa City enrolled 95 participants with RRMS into their randomized study comparing the effects of Wahls modified Paleolithic elimination diet and the Swank low-saturated fat diet on these individuals. The investigators collected measurements, including fatigue outcomes based on the FSS and MFIS, physical and mental quality of life outcomes based on the MSQoL-54, and the 6-Minute Walk Test (6MWT) at four separate times: 1) run-in, 2) baseline, 3) 12 weeks, and 4) 24 weeks. Of the 95 enrollees, 77 completed 12 weeks and 72 completed the full 24 weeks.

Additionally, investigators analyzed other important variables to determine if they played roles in influencing the outcomes. These variables included age, gender, body mass index, baseline Vitamin D levels, baseline 6-minute walk distance, walking assistance, alcohol consumption, smoking status, use of disease modifying therapies, and number of years since initial MS diagnosis.

The Swank diet restricted intake of saturated fats to less than or equal to 15 grams/day while allowing 20-50 grams/day of unsaturated fat and 4 servings each of fruits, vegetables, and grains, with preference for whole grains. The Wahls diet suggested 6-9 servings of fruits and vegetables with 6-12 oz of meats per day based on gender. The Wahls diet excluded grains, dairy, legumes, eggs, and nightshade vegetables for the first 12 weeks of the study with the sole reintroduction of nightshades during the 12-week follow-up period.

Limitations of the study included the short duration of the intervention, use of participant self-reported data for outcome measures, lack of diversity in study participants, lack of a control group with a normal diet, and lack of confirmation of diet adherence using biomarkers. Another limitation, according to the study, is that it is only generalizable to individuals experiencing fatigue from RRMS.


Wahls TL, Titcomb TJ, Bisht B, et al. Impact of the Swank and Wahls elimination dietary interventions on fatigue and quality of life in relapsing-remitting multiple sclerosis: the WAVES randomized parallel-arm clinical trial. Mult Scler J Exp Transl Clin. 2021;7(3). doi:10.1177/20552173211035399