Dr. Dean Ornish and Dr. Sarah Hallberg both agree that people should be eating “real” food instead of the highly processed food Americans find all too convenient. However, that is where the similarities stop; if the two ever discussed the matter of health promotion and disease prevention, their disagreement would probably boil down to one macronutrient: fat.
Dr. Ornish discusses the 67% higher fat loss seen in people who limit fat intake instead of carbohydrate intake. Dr. Hallberg proposes limiting what she refers to as “GPS” – grains, potatoes, and sugars, and emphasizes that a person’s diet should be composed of mostly fat. Yes, these views are quite contradictory but this idea that fat should be the star macronutrient in an individual’s diet is also quite contradictory to a lot of evidence-based health guidelines. In the field of dietetics, we are taught to evaluate nutrition research carefully, assessing how the results of a study fit into a larger body of existing evidence. Results that oppose accepted dietary guidelines should raise speculation. That is not to say a novel idea or concept has no place in nutrition research, but further evaluation is absolutely necessary. Additionally, nutrition education and implementation for this type of diet will be especially difficult in low SES populations if Dr. Hallberg expects them to purchase the high quality food ingredients she mentions in her TED talk. Coconut oil for example starts at about $7 at Walmart.
I also wonder what Dr. Ornish would have to say about the genetic impact of a high fat diet, as he discusses in his interview that his proposed diet (focuses on whole and plant-based food and limits refined sugars, animal protein, dangerous fats) can turn on “good” genes and turn off “bad” genes. I am sure he might also mention something about clogged arteries and this idea of “mortgaging your health” for immediate outcomes, such as weight loss. This high fat diet definitely sounds like it comes at a cost, especially considering the lethargy and brain fog a person might experience if their body is utilizing fat as it’s primary fuel substrate. Not only would this make incorporation of physical activity difficult, it would probably decrease quality of life.