A recent press release about a study at the University of Melbourne reads “Diabetes expert warns paleo diet is dangerous and increases weight gain.” The headline is based on a study by Dr. Andrikopoulos at the University of Melbourne. Being in my area of research (effects of diet in mice), I looked into this study and was surprised by the misleading nature of the press release.
The study examined the effect of mice eating a high fat (81% fat), low carbohydrate diet or a standard low fat mouse chow (10% fat). The diet tested was not a “paleo” diet, but a ketogenic diet. It contained cocoa butter, casein, sucrose, canola oil, and butter.
The strain of mice used in the study is called New Zealand Obese (NZO) for their unusual propensity to become enormously obese, even on a low fat diet. The mice are genetically identical, so the results cannot be generalized to a population. An analogy would be studying the effect of a diet in one morbidly obese person and extrapolating the results to an entire population.
The health consequences of the high fat diet on NZO were mixed, though this is not evident from the headlines. Over nine weeks, the average weight of the low fat group increased by about 50%, while the high fat group had a 90% increase. Glucose tolerance was decreased in the high fat group, indicative of worsening blood sugar control. However, the blood profile generally improved in the high fat group as HDL cholesterol increased and serum triglycerides decreased.
Again, this study was performed on just one type of genetically identical mice. The same type of diet has been shown to decrease body weight and increase metabolic rate in a more commonly used strain, C57Bl/6. Two mouse strains (and probably two people) can have opposite effects from the same diet. Thus, it is important to examine the effects of any intervention in a panel of genetically diverse mice rather than extrapolating the effect on any one strain to a population.
Dr. Andrikopoulos’ research group has found an identified an interesting result, but the headlines simply do not match the study results and are not representative of the larger body of scientific evidence on high fat, low carbohydrate diets.