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McDougall Interview with Dr. Roy Swank, MD

Updated August 27, 2013

Dr. Roy Swank, MD

Dr. Roy Swank, MD is the founder of the Low Fat Diet treatment for multiple sclerosis. Dr. Swank served as the head of the Division of Neurology of the University of Oregon Medical School (Oregon Health & Science University) for 22 years, and has published many papers in the most respected scientific journals on this subject. The following is a transcript of an interview with Dr. Swank conducted by John McDougall in 1998:

John McDougall (JM): Dr. Swank, most of us have heard of MS; could you give us a rundown on what the life of a person with MS is like?

Swank: These people are all energetic before they get the disease–they are driven people, always wanting to be busy. Once they get the disease they can’t be that active. So fatigue becomes a very important symptom. Then they begin to have neurologic symptoms, with repeated exacerbations, until they become quite disabled. They may have double vision or blindness at one time or another. They may lose control of their bladder, arm or leg. There is usually a partial recovery from these attacks, but they reoccur and become more severe. Soon patients have difficulty walking, they lose their balance and become clumsy; they have numbness and tingling, and sometimes burning. These things continue on and the course is steadily downhill. At about 10 to 15 years they often end up confined to a bed or wheelchair. Because of the disability and fatigue, they lead a very frustrated life. Patients go from a cane to a wheelchair to bedridden. Only about 5 to 10% of patients have a milder type of disease that does not result in this 0gloomy future.

JM: Forty years ago you figured out that MS was caused by food. How did you reach this conclusion?

Swank: At that time doctors thought MS had something to do with geography, because as you got further away from the equator the disease became more common. Scientists thought it might be due to magnetic fields, but I reasoned it could be a matter of food. The further north you go, the less vegetarian people become, and the more carnivorous they are.

Looking at the literature and going over the United Nations food intake throughout the world after WW II, it was quite obvious that multiple sclerosis and heart disease both occurred in areas where large amounts of saturated (animal) fat were consumed. It was surprising to find that those populations with a high incidence of MS were those who consumed more than 100 grams of fat a day; where the disease was uncommon they consumed less than 50 grams of fat a day. For example, there was no MS in the Orient. I soon discovered that during World War II people in Western Europe, when food was scarce, had less MS and fewer attacks if they already had the disease. People living in prison camps during the war had no MS, but when they got out and returned to meats and dairy products they starting developing MS.

At one point we did a survey in Norway, which showed a high incidence of the disease in the small dairy farming areas in the mountains where the fat intake was very, very high. Along the coastal fishing villages, the saturated fat intake was very low, and they had very few cases of multiple sclerosis. When you compared the two areas there were eight times as many MS cases in those mountainous, high-saturated-fat consuming areas than along the coast where they were primarily fishermen.

JM: Some of your early work showed the effects of fat on circulation.

Swank: We found a heavy-fat diet caused changes in circulation. After a typical, high-fat American meal red blood cells become very sticky and would bind to one another. About three hours after a meal they aggregated together to form clumps. And these clumps are large enough and tough enough so they can obstruct circulation in small capillaries throughout the body. We have also seen these changes in animals after feeding them a high-fat diet, and we also found a breakdown of the blood-brain barrier in these animals. I think this kind of injury results in the perivascular lesions (damage around blood vessels classically seen in MS) that are typical of MS.

JM: How did you start treating patients with MS with a low-fat diet?

Swank: We started treating patients at the Montreal Neurological Institute where we did studies comparing people on low-fat diets and high-fat diets. In our initial study of 25 patients, six did not go on the diet and, of these, five soon died, but of the 20 that went on the diet, only one died and the other 19 remained exactly the same as when they started, in other words no disability after 35 years (This was published in the Lancet1 in 1990).

At the University of Oregon, we found that patients who adopted a very low-fat diet, following an early diagnosis of MS, had a 95% chance of remaining free from further disability. When we compared our patients, after 35 years; the group who strictly followed a low-fat diet had a death rate of 31%. They not only avoided death from MS, but also death from heart and other diseases. Those who followed a high-fat diet had a death rate of about 80%.

But, they have to follow the diet strictly because even small amounts of fat make a big difference. In the study we published in the Lancet in 1990, we found that a difference of eight grams of saturated fat intake daily resulted in a threefold increased chance of dying from multiple sclerosis.1 (That means daily consumption of as little as one ounce of pork sausage at 10 grams, one medium cooked hamburger at 14 grams, an additional three ounces of porterhouse steak, or 2 ounces of cheddar cheese at 12 grams, significantly increases the risk for victims of MS.)

JM: You must have had people charging your doorstep, scientists from all over the world wanting to know about this wonderful low-fat diet treatment. The MS Society must be bending over backwards to tell people about your miraculous accomplishments.

Swank: Not really. You know, most people in this country expect to be cured by a pill, and have a cure that is almost instantaneous. With the low-fat diet, the people actually have to work to get better, and have to cure themselves. And as far as the MS Society, John, they don’t mention it because they didn’t discover it. It wasn’t their research dollars that found this treatment. So they’re not going to tell anybody. I discovered it in my small office here, in the basement of the University of Oregon Medical School.

JM: Was there any interest at all in diet back in the 1940s and 50s?

Swank: No, I was more or less considered a quack. I wondered why doctors felt this way. I think one of the reasons was economics. It doesn’t cost much to eat well and take care of yourself with a highly vegetarian diet. I was originally brought on board at the University of Oregon because of my interest in fats. The cardiologists felt there was some value in this.

JM: What does the Swank Diet consist of?

Swank: Most importantly it is a very low-fat diet. We use a little bit of animal protein in the form of skim milk, egg whites, fish, and the white meat of turkey and chicken. Otherwise, it is a low-fat vegetarian diet. We have found over the years that the vegetable oils can be added, from 10 to 30 grams a day, unless one is overweight.

JM: What do you think about adding vegetable oils to your diet?

Swank: Well, I think it’s worthwhile. We have looked at this over a number of years, and have found that the skin and the hair seem better in women. There is also some reserve of calories for energy. Best of all, however, is the fact that the patients can follow the diet more easily if they can have some oil. It makes it more palatable for them.

JM: Would you get upset at them if they decided they wanted to avoid the oil because they were too fat?

Swank: No. I vary the oil for that particular reason. If they are too heavy I cut back on the oil, and we absolutely cut out all saturated fats. We only allow about 10 grams of saturated fats, and that’s about as low as we can get it.

JM: Are there other things an MS patient should do?

Swank: Exercise, but don’t exercise to the point where you tire yourself out, and take a nap, one hour at least around the middle of the day. That is very helpful. The fatigue is sometimes so great that it is more disabling than the neurological problems. We see this fatigue lessen on a low-fat diet. Every month, patients will be able to increase the amount of exercise they can do.

JM: You are now 90; what are you going to do for the next 15 to 20 years?

Swank: I’m just going to hang in there. I just love seeing people in my office. I only work part time. But I love to work with healthy people who are so enthusiastic. (Dr. Swank retired at age 91 in the year 2000. He is now living with his wife outside of Portland, OR and still consults informally with some of his former patients.)


Multiple Sclerosis (MS) is a chronic progressive neurologic disease found in genetically susceptible people. An estimated 250,000 to 350,000 people are affected with MS in the USA. This disease develops between the ages of twenty and fifty, and is characterized by recurrent attacks on the nervous system. After 10 years, even with the best treatment modern medicine can offer, half will develop progressive MS, and will require some form of walking aid within 15 years following the onset of MS – and mortality is increased four-fold over the general population in patients with advanced disability.5 Therefore, any person suspected of having multiple sclerosis should consider this a very life-threatening disease and look into all reasonable possibilities to arrest its progress.

Worldwide, the incidence of multiple sclerosis crosses all racial barriers and geographical boundaries, and is common in Canada, the United States and northern Europe. However, it is rare in Africa, Japan, and other Asian countries. This difference most likely reflects the richness of the population’s diet. Scientists have found a very strong positive correlation when consumption of cow’s milk is compared with the incidence of MS worldwide.6,7

One theory proposes that cow’s milk consumed in infancy lays the foundation for injuries to the nervous system that appear later in life.8 Cow’s milk contains one fifth as much of an essential fat, called linoleic acid, as does human mother’s milk. Children raised on a linoleic acid-deficient, high-animal fat diet – as are most kids in our modern affluent society – are quite possibly starting life out with a damaged nervous system, susceptible to insults and injuries in later life. The possible sources of injury that can precipitate the attacks of multiple sclerosis in mid-life are suspected to be viruses, allergic reactions, and/or disturbances of the flow of blood to the brain caused by a high fat diet.

Another theory proposes an autoimmune basis for this disease. MS has much in common with autoimmune type 1 diabetes mellitus, including nearly-identical ethnic and geographic distribution, and genetic factors.9,10 The damage to the nervous system may occur through a process known as molecular mimicry. In susceptible people, cow’s milk protein may enter the bloodstream from the intestine. The body recognizes this as a foreign protein, like a virus or bacteria, and makes antibodies to it. Unfortunately, these antibodies are not specific only to the cow’s milk protein and they find similar proteins in the nervous system (the myelin). The antibodies attach to these tissues and destroy them. In the case of diabetes, the antibodies looking for cow’s milk protein attack the insulin-producing cells of the pancreas (See the July 2002 McDougall Newsletter). These kinds of diseases are known collectively as autoimmune diseases and include rheumatoid arthritis, nephritis (kidney disease), lupus, arteritis (artery disease) and many other common diseases.

Therefore, people seeking to effectively treat MS and wanting to avoid progression of their disease need to eat a healthy, low-fat, plant-based diet as recommended by Dr. Swank. Considering recent evidence, strict avoidance of all animal proteins, especially dairy proteins, is also very important.

For more information see Hot Topics on Multiple Sclerosis.


  1. Swank R. Effect of low saturated fat diet in early and late cases of multiple sclerosis. Lancet. 1990 Jul 7;336(8706):37-9.
  2. Swank R. Multiple sclerosis: fat-oil relationship. Nutrition. 1991 Sep-Oct;7(5):368-76.
  3. Swank R. Multiple sclerosis: the lipid relationship. Am J Clin Nutr. 1988 Dec;48(6):1387-93.
  4. Swank R. Multiple sclerosis: twenty years on low fat diet. Arch Neurol. 1970 Nov;23(5):460-74.
  5. Weinshenker BG. The natural history of multiple sclerosis. Neurol Clin. 1995 Feb;13(1):119-46.
  6. Butcher J. The distribution of multiple sclerosis in relation to the dairy industry and milk consumption. N Z Med J. 1976 Jun 23;83(566):427-30.
  7. Malosse D. Correlation between milk and dairy product consumption and multiple sclerosis prevalence: a worldwide study. Neuroepidemiology. 1992;11(4-6):304-12.
  8. Agranoff BW. Diet and the geographical distribution of multiple sclerosis. Lancet. 1974 Nov 2;2(7888):1061-6.
  9. Winer S. T cells of multiple sclerosis patients target a common environmental peptide that causes encephalitis in mice. J Immunol. 2001 Apr 1;166(7):4751-6.
  10. Lauer K. Diet and multiple sclerosis. Neurology. 1997 Aug;49(2 Suppl 2):S55-61.