Guest post by Grant Schofield, Professor of Public Health at Auckland University of Technology and Director of the Human Potential Centre.
Another week, another warning that the paleo diet is not really where its at, especially for diabetes.
The paleo diet – the idea that we should be guided in human nutrition/public health nutrition by evolutionary history is steeped with controversy. Health experts and authorities are seemingly going well out of their way to make sure people are warned off such ways of eating.
Proponents are often mystified by this, because the idea of using human evolutionary history to understand human function is common in human biology. In fact its a guiding principle. As well, in the midst of a chronic disease epidemic, including diabetes and obesity which are potentially improved by this approach, you’d think approaches which are based on whole food eating, and appeal to at least some of the population would be welcomed.
I find it curious that other approaches such as vegetarianism, which are often based not around science, but religion and other beliefs are welcome in public health nutrition advice. Yet the paleo approach is not.
Yes, people who are follow this way of eating are restricted to eating much less processed food and often lower carbohydrate diets. Neither of these approaches are known to be anything but beneficial for human health, especially in the context of diabetes.
As the author of a recent review of low-carbohydrate diets for diabetes in the New Zealand Medical Journal, we appreciate that Professor Sof Andrikopoulos’s article on Paleolithic (“Paleo”) diets for diabetes in the Australian Medical Journal was a fairer summary of the limited evidence, and his references to low carbohydrate diets for diabetes were more positive and consistent with the evidence than his comments in the mouse study in Nature Nutrition and Diabetes which he coauthored earlier this year. In his media activity after the mouse study he extrapolated wildly from the mouse feeding study to the paleo diet in humans. This wasn’t helpful for public health.
He does continue his anti-paleo attacks, more or less evidence free, on a couple of fronts which do need to be exposed. First, he contends that people on paleo diets are at risk nutrient deficiencies (specifically fibre and calcium) by not eating whole grains. A claim which has absolutely no basis in reality or even theory. Nutrient profiles of people on paleo diets and similarly constituted low carb diets show no evidence of producing nutrient deficiencies. We are unaware of any condition ever recorded because of avoiding grains and eating whole foods from plants and animals instead.
He claims that “And high-fat, zero-carb diets promoted by some celebrities make this worse, as they can lead to rapid weight gain, as well as increase your risk of heart disease.” This is startlingly incorrect. Low carb diets are known to be useful in reducing weight and hanging diabetes.
Though we lack a universally agreed definition for the Paleo diet, the Paleo diet for diabetes, as used in practice, and as promoted in Australia by Pete Evans is merely a low-carbohydrate diet with some additional restrictions. Some of these restrictions are, in our view, unnecessary for most people with diabetes, but they are unlikely to prevent the Paleo diet from having the same benefits as other whole-food diets equally those restricted in carbohydrate.
Diabetes and the paleo diet
The defining feature of diabetes is high blood glucose; the liver should stop releasing glucose when we eat carbohydrate, but in diabetes it does not, due to insulin resistance or, in type 1 diabetes, the absence of insulin. The resulting combination of high blood glucose, combined with excessive insulin concentrations in the insulin resistant, causes the complications of diabetes, and can also play a role in conditions such as cardiovascular disease in those without a diabetes diagnosis.
When the diet of someone with type 2 diabetes is low in carbohydrate, the liver no longer releases glucose from glycogen after meals. The reduced glucose concentration and insulin response, the drop of elevated blood pressure due to increased excretion of sodium, and the weight loss that is usual when carbohydrate calories are restricted all result in an improvement in the clinical picture, shown by a reduction in medication requirements. This is a simple and logical solution to diabetes management on first principles. Glucose from the diet puts of blood sugar and further stimulates extra production of it by the liver. So don’t eat it in the first place!
So we end up with this continuing determination to go well beyond the evidence in claiming a lack of evidence. In my world that’s the pot calling the kettle black. What we do need are a range of dietary practices which are effective in helping people manage their health and well being. For some, the paleo template makes sense and they will find their way to good health. I ask again, why paleo eaters are a target, and not the commercial food companies promoting highly processed food, the health system that is dominated by big pharma, and the health system that does sickness not heath?
Surely we have bigger fish to fry?