The Swank diet: a guide for MS

The Swank diet is one of the oldest and best known eating plans associated with multiple sclerosis. It was developed by Dr Roy Swank, an American neurologist, after he noticed that MS appeared less common in coastal Norwegian communities that ate more fish and less saturated fat than inland farming communities.

Swank's theory was that a diet very low in saturated fat could slow the progression of MS. He followed a group of patients for decades and reported that those who stuck closely to the plan had fewer relapses and less disability than those who did not. It remains a low saturated fat, low processed food, fish-forward way of eating.

• Saturated fat limited to around 15 grams a day
• Unsaturated oils allowed, roughly 20 to 50 grams a day
• No red meat at all in the first year, then very small amounts weekly
• No processed foods containing saturated fat or hydrogenated oils
• Dairy only if it is fat free
• White fish and shellfish in any amount, oily fish in moderation
• Plenty of fruit, vegetables and wholegrains
• A daily cod liver oil and multivitamin supplement

Porridge made with skimmed milk and berries for breakfast, a lentil soup with wholegrain bread at lunch, grilled white fish with rice, olive oil and a large salad for dinner, and fruit or fat free yoghurt in between. In practice it feels close to a Mediterranean diet with much stricter limits on red meat, butter, cheese and pastry.

Swank's own long-term results are striking, but the study was observational rather than a randomised trial. People who could stick to a demanding diet for decades may have differed in other ways, and MS varies naturally between individuals, so the findings cannot prove cause and effect.

More recent research has compared low saturated fat plans with other approaches. Small trials have found improvements in fatigue and quality of life, but the evidence is not yet strong enough for any diet to be recommended as a treatment for MS. Most MS organisations suggest a balanced, heart-healthy diet, which the Swank plan broadly is.

• It is restrictive, and cooking or eating out takes more planning
• Very low fat intake can affect absorption of fat soluble vitamins
• It can be hard to maintain on low-energy days, which is when it matters most
• Unintentional weight loss is a risk if portions are not managed

The Wahls protocol takes almost the opposite approach, favouring higher fat and a paleo-style focus on vegetables and meat. The Overcoming MS programme is closer to Swank, adding exercise, vitamin D and stress management. The Mediterranean diet is the least restrictive and has the broadest general health evidence behind it.

Talk to your MS team or a registered dietitian first, especially if you take disease-modifying therapy, have other conditions, or are underweight. A diet you can sustain and enjoy will almost always beat a stricter one you abandon after a month.