Comparing the effects of the Swank and Wahls diets on multiple sclerosis symptoms Original paper

Fatigue is one of the most debilitating symptoms of multiple sclerosis (MS), but the drugs available to treat this symptom are limited. For this reason, many people with MS seek nonpharmacological approaches, particularly diets, to treat their fatigue and improve their quality of life. The Swank (a low-saturated-fat diet) and the Wahls (a modified Paleo diet) dietary protocols have some preliminary supporting evidence for treating MS symptoms, but large randomized trials have not been conducted, so there is insufficient evidence for clinicians to recommend these diets to patients.

In this 36-week parallel-group trial, 87 participants with relapsing-remitting MS (periods of stability interrupted by new or worsening symptoms) were randomized to follow either the Wahls or Swank diet. After a 12-week run-in period, the participants adhered to their assigned diet for 24 weeks.

The Swank diet consists of 20–50 grams of unsaturated fat and four servings of whole grains, fruits, and vegetables and restricts saturated fat to ≤15 grams per day. The Wahls diet consists of 6–9 servings of fruits and vegetables and 6–12 ounces of meat and restricts grains, legumes, eggs, and dairy (excluding butter or ghee). For the first 12 weeks, nightshades (bell peppers, eggplants, potatoes, etc.) were restricted in the Wahls group and reintroduced under the guidance of a registered dietitian for the second 12 weeks. The participants were instructed to eat their diet ad libitum and to take several supplements daily (1 teaspoon of cod liver oil, 1,000 µg of methyl-B₁₂, 1,000 µg of methyl folate, a multivitamin without iron, and 5,000 IU of vitamin D₃ or an amount that achieved a serum range of 40–80 ng/mL).

The primary outcome was the change in perceived fatigue at 12 weeks, as assessed by the Fatigue Severity Scale (FSS). The secondary outcomes were perceived fatigue assessed by the Modified Fatigue Impact Scale (MFIS), mental and physical quality of life assessed by the Multiple Sclerosis Quality of Life-54 (MSQoL-54), and the 6-minute walk test (6MWT), followed by a 12-week follow-up period.

Similar reductions in FSS scores at 12 and 24 weeks were seen in both the Swank (-0.94 and -1.01) and Wahls (-0.71 and -1.31) groups. MFIS scores were also reduced at 12 and 24 weeks in the Swank (-9.87 and -10.5) and Wahls (-14.4 and -19.1) groups, reflecting a greater reduction in the Wahls group that was statistically significant.

For the MSQoL-54, the Swank group improved at 12 weeks (mental: +3.9; physical: +6.04) and at 24 weeks (mental:+5.9; physical +9.25). These scores also improved in the Wahls group at 12 weeks (mental: +11.4; physical: +14.5) and 24 weeks (mental: +14.0; physical: +17.2). The 6-minute walk test was not improved by either diet.

The lead author of this study is Terry Wahls, creator of the Wahls diet.