Research Review: Three Popular MS Diets Compared + Why Study Design Matters

Two papers caught my attention this week, both in reference to a long-term diet study for people with MS. Below you'll find a brief summary of the research, along with my key takeaways

Fasting, Ketogenic, and Anti-Inflammatory Diets in Multiple Sclerosis: A Randomized Controlled Trial with 18-Month Follow-Up (BMC Nutrition, 2025)

This study compared three different dietary approaches in people with relapsing-remitting multiple sclerosis over 18 months. Researchers enrolled 105 people and assigned them to follow either a standard healthy diet (vegetarian-focused with omega-3 emphasis), a fasting diet (reduced calories for 7 days every 6 months plus time-restricted eating), or a ketogenic diet (20-40 grams of carbs, 70-80% fat from plant sources). ^{(1, 2)}

The researchers wanted to see if ketone bodies (produced during fasting and ketogenic eating) could protect brain tissue better than a standard healthy approach. They measured new brain lesions on MRI, cognitive function, mood, fatigue, quality of life, and various blood markers of brain health and metabolism. All participants were on stable MS medications throughout the study, so these dietary approaches were used alongside conventional treatment.

Unfortunately, 21% of participants dropped out during the study due to the COVID-19 pandemic, which made it difficult for the study to show significant findings. When we conduct a dietary intervention study, we routinely project a 30% drop out to help make sure we have enough people to detect the difference between groups. The good news here is that there were no new brain lesions in any of the three diet groups, and all participants saw improvements in metabolic health markers.

The most interesting findings were the trends toward improvement in specific areas:

• The ketogenic diet group showed better performance on tests of thinking and working memory
• The fasting diet group experienced improved mood over time
• Both the fasting and ketogenic groups had greater improvements in metabolic health compared to the standard healthy diet group

My Takeaway

This was an exciting study because it was much longer than most diet studies. It also included brain MRI imaging, blood biomarkers linked to neurological damage, clinical assessments, and patient reported outcomes. I’m encouraged by these types of larger, longer diet studies being conducted, and I’ll be watching to see how they evolve over time.

This research reinforces that improving nutritional quality matters for people with MS, regardless of which specific approach you choose. The trends suggesting that fasting approaches may help with mood and ketogenic eating may support cognitive function are encouraging, even though the study couldn't prove definitive benefits.

In my clinical experience, ketogenic diets require more discipline and can be socially challenging—something this study confirmed. Time-restricted eating tends to be more sustainable long-term for most people.

My general recommendation for people with MS looking to improve their function is to start with the basics: eat more non-starchy vegetables, reduce or eliminate added sugars, and consider adding time-restricted eating. I also recommend fundamental nutritional support including vitamin D3+ vitamin K2, a quality multivitamin/ multimineral, fish oil, and magnesium—all of which I've included in my Basic Support Kit for convenience.

Citations:

1. Bahr LS, Bock M, Liebscher D, Bellmann-Strobl J, Franz L, Pruss A, et al. Ketogenic diet and fasting diet as Nutritional Approaches in Multiple Sclerosis (NAMS): protocol of a randomized controlled study. Trials. 2020;21(1):3.
2. Bahr LS, Bellmann-Strobl J, Koppold DA, Rust R, Schmitz-Hubsch T, Olszewska M, et al. Fasting, ketogenic, and anti-inflammatory diets in multiple sclerosis: a randomized controlled trial with 18-month follow-up. BMC Nutr. 2025;11(1):167.