Of Oil and Ethics
I have a question in my inbox from someone asking if there “is anything to the ‘no oil’ diets,” such that Dr. Caldwell Esselstyn promotes. My answer is – certainly there is something to it. Dr. Esselstyn (1) and Dr. Dean Ornish (2) have used a very low-fat, plant-based diet (10% of the calories as fat) as part of a cholesterol-lowering program that has decreased the amount of plaque in patients’ arteries and led to much better outcomes than typical treatment for heart disease. Dr. Neal Barnard and the Physician’s Committee for Responsible Medicine have used a very low-fat, vegan diet to treat type-2 diabetes with impressive outcomes (link).
But is it the only healthy diet that all vegans should eat? Let’s look at some other evidence.
A 2000 cross-sectional report (3) on cholesterol levels in men from EPIC-Oxford found the following:
So the vegan men were eating a diet of 30% of their calories as fat while still maintaining cholesterol levels of 158 mg/dl. Some people would consider this level of cholesterol too high, and while trials of people with heart disease who lower their cholesterol levels to below 150 mg/dl have shown a great benefit in doing so, it is not clear (to me, anyway) that people without a history of high cholesterol and heart disease need to go as low as 150 mg/dl. Low calories (or body weight) and saturated fat may be the most important aspect of lowering cholesterol levels.
A cross-sectional study on cholesterol levels is not the highest form of evidence compared to the clinical trials I mentioned earlier. What about trials of higher fat diets?
The Eco-Atkins diet, a high-protein, higher fat version of a vegan diet found better changes in blood lipids and higher levels of satiety when compared to a lower fat, near-vegan diet (4). But this trial only lasted 4 weeks, not nearly long enough to measure heart disease outcomes. Cholesterol levels of the people on Eco-Atkins went from 257 to 205 mg/dl – nowhere near as low as the very low-fat diets generally achieve, but, again, it was only four weeks long. [2014 Update on Eco-Atkins]
Most of the very low-fat diets do not allow for many nuts. While nuts have consistently been associated with positive health outcomes (lower body weight, better cholesterol levels, etc.), one vegan doctor, who uses low-fat diets to treat heart disease, told me that many of his patients binge on nuts when they are part of their diets and so he suggests they avoid them. I’ve heard from others that if they eat nuts they gain weight. It doesn’t completely surprise me that someone on a very low-fat diet might binge on nuts – they might be craving the fat or protein. But if you are someone who can eat nuts in moderation, then having some is most likely beneficial for preventing heart disease and long-term weight maintenance.
Though it may be rare, or even extremely rare, some people who follow a very low-fat diet find that they lose their libido and regain it upon eating more fat.
Earlier this month, Jeff Nelson of Vegsource.com wrote an article, How the ethical argument fails veganism. In it, he disagrees with my co-founder of Vegan Outreach, Matt Ball, and my co-author of Vegan For Life, Ginny Messina, as to whether the health argument is the way to go when spreading veganism. He also disparages “AR dietitians” in general, of which I can’t help but notice that I am one.
Aside from the fact that Matt nor I care about veganism as anything more than a tool for protecting animals and the environment, the central thesis of Nelson’s article is that people who become vegan for health reasons are more likely to stick with the diet than people who go vegan for ethical reasons. He says that people who go vegan for ethical reasons are usually not as educated about health and nutrition due to being persuaded by organizations that do not give them adequate information; so they eat processed foods and end up concluding that a vegan diet is not healthier. The people who go vegan for health reasons, on the other hand, understand the importance of avoiding processed foods and oils, and their health improves.
While many people do well on a whole-foods only, very low-fat vegan diet, my experience has been that such diets can sometimes result in failure to thrive, while many people do thrive on a vegan diet that includes more fat and processed foods.
The vegans I know are mostly animal advocates, and, therefore, are dedicated to being vegan. Very few of them had been diagnosed with heart disease or type-2 diabetes before becoming vegan, so they are not necessarily in the same boat as people who become vegan to treat their disease. The vast majority of the vegan, animal advocates I have know have stayed vegan, and most eat processed foods. From soy foods to french fries to desserts made with white flour and sugar, the vegans I know eat ’em. Of course, most of them also eat more fruit, vegetables, whole grains, legumes and nuts than the average American.
My cholesterol tends to be around 150 mg/dl. If I were eating a very low-fat diet, it might be even lower, possibly decreasing my risk for heart disease. But I crave protein and feel better when eating a good amount, possibly due to my fairly intensive weight lifting. I do much better eating soyfoods and other processed foods such as pasta, than when eating only whole plant foods.
There are health issues that might prevent people from eating only whole foods, such as digestive problems, and those have to be dealt with on a case by case basis.
I generally tell people who have metabolic syndrome that they should tend towards a whole-foods diet, greatly limiting added oils but including nuts, while those who are not as much at risk can afford to eat more processed foods, especially those high in protein and/or pastas (which generally do not raise blood sugar as high as other processed grains). Monitoring your weight, cholesterol, and blood sugar levels is a good idea to see if the diet you are eating is working for you.
At some point there might be clinical trials examining cardiac outcomes in people on vegan diets that are not so low in fat or in vegans who have not been diagnosed with heart disease. We do have some data on heart disease in vegans from the 1999 meta-analysis, but it isn’t much.
1. Esselstyn CB Jr. Updating a 12-year experience with arrest and reversal therapy for coronary heart disease (an overdue requiem for palliative cardiology). Am J Cardiol. 1999 Aug 1;84(3):339-41, A8. | link
2. Ornish D, Scherwitz LW, Billings JH, Brown SE, Gould KL, Merritt TA, Sparler S, Armstrong WT, Ports TA, Kirkeeide RL, Hogeboom C, Brand RJ. Intensive lifestyle changes for reversal of coronary heart disease. JAMA. 1998 Dec 16;280(23):2001-7. Erratum in: JAMA 1999 Apr 21;281(15):1380. | link
3. Allen NE, Appleby PN, Davey GK, Key TJ. Hormones and diet: low insulin-like growth factor-I but normal bioavailable androgens in vegan men. Br J Cancer. 2000 Jul;83(1):95-7. | Link
4. Jenkins DJ, Wong JM, Kendall CW, Esfahani A, Ng VW, Leong TC, Faulkner DA, Vidgen E, Greaves KA, Paul G, Singer W. The effect of a plant-based low-carbohydrate (“Eco-Atkins”) diet on body weight and blood lipid concentrations in hyperlipidemic subjects. Arch Intern Med. 2009 Jun 8;169(11):1046-54. Erratum in: Arch Intern Med. 2009 Sep 14;169(16):1490. | link