More Science and Less Zealotry, Please.
The controversy over which diet is best for all has again made headlines with the publication of the Stanford University study in the Journal of the America Medical Association March 7, 2007. Since the results are favorable to the low-carbohydrate Atkins diet, the usual criticism can be expected to follow.
Predictably, Dean Ornish has launched a tirade in which he manipulates the study findings to find fault with the low-carb approach and to deflect criticism away from his ultra low-fat diet which did not perform well in the study. Unfortunately, this is an argument based on dogma and not on science. The science speaks for itself.
As scientists and clinicians, we believe that no one dietary approach is going to be ideal for everyone. There is no doubt that, for some, an ultra-low-fat approach may be appropriate. Unlike Dr. Ornish, we recognize that there is no one-size-fits-all approach to the enormously complex problem of obesity and related conditions. Unfortunately, other authoritative sources like the US dietary guidelines also recommend a single lowered fat high-carbohydrate diet approach and have been doing so over the decades that this epidemic has grown.
Gratuitous attacks on the Atkins diet that imply it involves abandonment of wholesome vegetables and fruit for “bacon and brie” are simply wrong. Even in the most restrictive phase it meets the recommended daily guidelines for vegetables and fruits. As one advances through the phases, low-glycemic fruits, more vegetables, legumes and even whole grains are introduced based on an individual’s metabolic tolerance for these foods. One survey found that people who follow the Atkins plan over the long term eat more vegetables than they did before. Another study found that rather than increase the intake of fat and protein to compensate when carbohydrates were reduced, people simply ate less.
The unfortunate reality of today is that too many Americans are eating potato chips and fries and drinking sugar-sweetened beverages. We support the idea that wholesome foods such as meat, fish, cheese and eggs along with vegetables and low glycemic fruits constitute a healthier diet than chips and fries and sodas.
While this study examined four popular dietary approaches, what is clear is that whatever approach one takes to healthy eating, success will depend on how well you can stick to it. In this case, and in many earlier studies, it is clear that the Atkins diet is the one most people can maintain. On the other hand, the extremely low-fat diet advocated by Dr. Ornish is very difficult to follow. In this study, the subjects who were supposed to reduce their fat intake to his recommended intake of 10% could not reach that target.
Another important aspect of this and earlier studies is the beneficial effect that reducing carbohydrates has on metabolic markers. In his criticism, Dr. Ornish states that the LDL-cholesterol level fell in response to his diet, but does not mention that none of the differences in LDL-C in this study were statistically significant. This is therefore not a scientifically valid criticism. On the other hand, it is widely recognized that elevating the HDL-C, the good cholesterol, is an important factor in reducing cardiovascular risk. In this study there was a highly significant 10% rise in HDL-C in the Atkins group but no such change among those who followed the very high-carbohydrate Ornish diet.
In the same vein, the Atkins group demonstrated a significant (both statistically and clinically) greater reduction in systolic and diastolic blood pressure than the other three diets. A difference in mean arterial pressure of 5 mm Hg is about the response we would expect to see with a first-line pharmaceutical in the clinical setting. Any objective observer would acknowledge this as a major beneficial effect of the Atkins diet.
Dr. Ornish suggests that the positive findings of research such as this that supports the Atkins diet will cause problems, and that “many people may go on a diet that harms them based on inaccurate information.” This is a wildly irresponsible statement, given the consistency with which a reduction in important metabolic and cardiovascular risks are achieved by lowering carbohydrate consumption. It is simply preposterous to suggest that an approach that leads to significant risk factor reduction is unhealthy.
The seriousness of the accelerating epidemic compels us to think outside the box to find new solutions where the status quo has failed. The only approach that will be successful is one that people can actually follow. This study adds to the mounting evidence that the Atkins diet is a healthy choice which should be supported as a viable way to lose weight and improve metabolic and cardiovascular risk factors.
The Real Atkins Lifestyle
Before there was research on the Atkins diet it was commonly criticized in the belief that it would elevate cholesterol, ruin one’s kidneys and bones and cause heart disease. None of this has been borne out by the research.
What is clear from this JAMA study, and others like it, is that cardiovascular risk factors actually improve when controlling carbs. The scientific studies of this approach have shown numerous times that a pattern of rising HDL-C and falling triglycerides is the hallmark of carb restriction and that this benefit occurs even in the absence of weight loss.
Research also shows that rising HDL-C (good cholesterol) and falling triglycerides is correlated with larger LDL-C particles which are less likely to cause heart disease. Even the much touted statin drugs do not deliver this kind of improvement in LDL-C particle size. On the other hand, the research shows that eating a high-carb diet and cutting fat intake results in small dense LDL-C particles that are linked to an increased risk of heart disease.
Importance of Fat
There are other problems associated with extremely low fat diets, as well. Cutting fat intake can lead to deficiencies in fat soluble vitamins, depletion of essential fats such as EPA and DHA, and decreases in the absorption of nutrients. Studies also show that people with cholesterol levels that are too low become prone to depression, suicide and cancer and have higher overall death rates than those who have higher cholesterol levels.
When all is said and done, it behooves us to remember that the diet debate is not a horse race where there is only one winner. We know there is a great variability in metabolic and genetic factors that will determine what dietary approach is best for each individual person. Although, in this and many other studies the Atkins diet worked better for more people, it is also evident that other dietary approaches will work for some people as well. The most important thing we have learned from dietary research is that people need to find the approach that will deliver healthy outcomes for them individually. And, just as the proof of the pudding is in the eating, the proof of a diet's effectiveness is whether it can sustain those benefits over the long haul. Hopefully, the weight of the evidence will now allow the Atkins diet to be recognized and supported as a legitimate option for people who want to improve their health through better nutrition.
On a final note, Dr. Ornish’s repugnant attempt to undermine Dr. Atkins’ credibility by perpetuating the myth that he had heart disease is unconscionable. It is unbecoming of any honorable person to make ad hominem attacks on those who are departed. Enough is enough. Dr. Atkins died of a head injury. He is no longer with us, but the line of scientific inquiry that he started continues to vindicate his dietary approach. And no amount of unfounded criticism will alter the fact that this study, and the 60 others before it, clearly demonstrate that what Dr. Atkins had been telling us all along was right.
- Jacqueline A. Eberstein, R.N. Co-author, Atkins Diabetes Revolution, President, Controlled Carbohydrate Nutrition
- Stephen D. Phinney, M.D. Ph.D Emeritus Professor, Department of Medicine, UC Davis, Elk Grove, Cal
- Mary C. Vernon, M.D., CMD, Co-author, Atkins Diabetes Revolution, President, American Society of Bariatric Physicians
- Eric C. Westman, M.D. M.H.S, Associate Professor of Medicine, Duke University Medical Center
- Jay Wortman, M.D, Department of Health Care & Epidemiology, Faculty of Medicine, University of British Columbia