The Paleo diet is the hottest diet in the world. It was ranked as the top diet related term searched in Google for 2013 and 2014. Celebrities are on it. Politicians are on it. It’s on the news. It’s what people are talking about.
It’s also controversial. Paleo advocates selecting foods based on evolutionary theories and principles. This doesn’t make sense to everyone. Some have argued that it’s impossible to know what our ancestors from the Paleolithic era ate. Others have argued that there is no clinical evidence to support Paleo.
A 2014 US News and World report ranking popular diets ranked Paleo tied for dead last, #35. Behind Slim Fast, behind Jenny Craig, behind Volumetrics, behind Ornish. They concluded there was scant evidence, and they were partially correct because there was no systematic review at the time. In an evidence-based healthcare system, it’s evidence that counts, not anecdotes. And the evidence should ideally come from a systematic review of randomized controlled trials (RCTs).
A systematic review and meta-analysis of RCTs can generate robust evidence, particularly when the trials are well-conducted and the outcomes are hard, objective outcomes. Although there have only been four RCTs of the Paleo Diet, they were all well-conducted. The outcomes we examined are the components of the metabolic syndrome, such as blood pressure, glucose, cholesterol, waist circumference, and triglycerides. These are the major predictors of chronic disease risk, particularly cardiovascular disease and diabetes. Our pooled analysis showed that the Paleo diet resulted in greater improvements in these outcomes compared to a standard guideline-based diet. The pooled results were not always statistically significant, but they favored the Paleo diet in all cases.
In the US News and World Report survey, the government-endorsed Dietary Approaches to Stop Hypertension snagged the top spot. Yet our meta-analyses compared Paleo to diets similar to DASH and Paleo came out on top.
Are dietary guidelines around the world recommending the wrong diet? It’s too soon to tell, but our meta-analyses warrant further evaluation of the health benefits of Paleolithic nutrition.
Loren Cordain recently wrote about milestones of research into the Paleo diet. No doubt when Loren updates his summary, he’ll mention our systematic review.