Groundbreaking Research Finds The Paleo Diet® Most Effective at Improving Markers of Chronic Illness
A recent, large-scale meta-analysis shows The Paleo Diet is better than the Mediterranean and DASH diets for overall control of cholesterol, glycemic control, and inflammation.
A healthier diet can play an important role in preventing chronic disease. The rapid rise of cancers, heart disease, and autoimmune conditions in recent decades means making changes to how we eat can help avoid years of medical expenses and a plummeting quality of life.
The biggest challenge for many people who care about their health is figuring out how to eat a healthier diet. What science considers healthy and what’s celebrated in the media often conflict, leading to debate and constantly changing guidance. Even top health experts will swear by vastly different dietary approaches, offering compelling testimonials on how an approach saved their life or that of a loved one.
And unfortunately, media reports on the scientific research can often make the choices more confusing. One minute, we’ll read about a study in the news showing that eating eggs is a sure-fire way to get heart disease and then the next minute there’s a report that eggs with a little omega-3 will keep your heart healthy for decades.
Fortunately, a recent and important meta-analysis comparing research on many of the current popular diets has helped clarify how diet can prevent non-communicable diseases.
The meta-analysis drew two conclusions:
- Overall, the Paleo Diet performed best at improving the markers of chronic disease.
- The researchers found that our specific food choices are what’s most important for improving chronic disease markers. Focusing on macronutrients alone, like following a low-fat diet or a low-carb diet, offers no guarantee of improving your health.
In other words, living a healthier life is about picking the right foods—natural foods that are less processed—and not focusing on their fat or carbohydrate content. A focus on specific foods is the common theme of the three topped-ranked diets in this study—The Paleo Diet, the DASH diet, and the Mediterranean diet.
Download a summary of this article and the study: The Paleo Diet Is Healthier than Mediterranean and DASH Diets (2 meg pdf).
Below is a graphic that summarizes the results of Dietary Patterns and Non-Communicable Disease Biomarkers: A Network Meta-Analysis and Nutritional Geometry Approach by S. Liang et. al. See how each diet affects biomarkers.
But before we dive further into the results, let’s ask an important question: Why is this meta-analysis such an important result for the field of healthy nutrition?
Meta-Analyses Build Consensus Among Scientists
The media is constantly publishing stories that start with “new research shows…” But what the media often overlooks is that scientists never draw broad conclusions from a single study, even if it was well conducted. A randomized control trial on eggs may give some indicators about eggs and cholesterol, but we don’t know if there were other unaccounted-for factors, if there was bias in the research, if some of the subjects were particularly sensitive to cholesterol, or if there simply weren’t enough people in the study.
This is why there are so many contradictory articles reporting on research. The media usually reports on a single new study.
Now, imagine if a journalist founds all of the articles written about eggs, removed the biased and low-quality articles, and then pulled the rest together to show what the remaining trustworthy articles said about eggs. This article drawing from many other reliable articles may reveal a consensus opinion that we could start to trust.
That’s basically what a meta-analysis does. Meta-analysis authors find all of the research on a particular subject, which is often thousands of studies. They remove the studies that don’t meet quality criteria—reducing the list to a hundred or fewer well-conducted studies—and then they pool the results together to draw conclusions based on all of the selected studies.
Meta-analyses are considered by many scientists to be the highest form of research and the closest science comes to drawing definitive conclusions.
So why is this important?
The First Comprehensive Meta-Analysis of Popular Diets and Non-Communicable Disease Prevention Puts The Paleo Diet on Top
Published in the respected, peer-reviewed journal Nutrients in December of 2022, a meta-analysis led by S. Liang, et. al. is the first large-scale meta-analysis looking into how popular diets affect the key markers of chronic disease. There have certainly been many claims in the press and on social media, but as Liang’s team pointed out, no one had done the hard work to determine what the science really had to say.
The researchers started with 4,008 studies which they narrowed down to 68 that met their inclusion and quality standards. They compared many of the most popular diets, including:
- Mediterranean diet
- The Paleo Diet
- DASH diet
- Plant-based diet
- dietary guidelines diet (diets based on a variety of current government recommendations)
- low- and high-Glycemic Index (GI) diets
- high-carbohydrate, low-fat diet
- low-carbohydrate, high-fat diet (e.g., ketogenic diet)
- A typical Western diet
Ideally, a study on disease prevention would put subjects on a diet and then track them to see if the rates of disease were lower in the diet group. The problem with this sort of study is that it would take decades. Instead, research tends to look at the biomarkers of chronic disease. For example, if your doctor gives you a blood test and finds your cholesterol is high, she’ll tell you you’re at risk of heart disease and need to get your cholesterol down. High cholesterol is a biomarker of heart disease. If you can lower this biomarker with diet, exercise, or medications, your doctor would expect your risk of heart disease to be lower.
“Emerging evidence has demonstrated health benefits of The Paleo Diet.”
The meta-analysis broke common chronic disease biomarkers into three categories:
- lipid markers, such as cholesterol, which are key indicators of heart disease
- glycemic control markers, such as insulin and resting glucose, which are key indicators of metabolic conditions like diabetes and Metabolic Syndrome.
- markers of inflammation, which are a risk factor for the broadest number of non-communicable diseases including heart disease, cancer, and autoimmune disease.
After statistically integrating the data from all 68 studies, the researchers used a popular and powerful statistical tool to rank the diets called the surface under the cumulative ranking curve or SUCRA. SUCRA is a well-known research tool used among meta-analysis studies. The SUCRA number is a score from zero to 100% that compares all the treatments included in a study or analysis. Higher SUCRA scores indicate that a treatment is more likely to be effective than lower-scored treatments. In this particular meta-analysis, a higher SUCRA score means that a diet is more likely to be effective than other diets at improving the biomarkers of chronic diseases. In other words, if one diet earns a SUCRA score of 70% while another earns a 35%, the higher scored diet is twice as likely to cause improvements.
When all the biomarkers were merged to give an overall ranking, The Paleo Diet came out on top at 67%, followed by the DASH diet at 62% and the Mediterranean diet at 57%. The Western diet (a typical diet consisting of highly processed foods) was at the bottom of the list at 36%.
“When combining all three categories, The Paleo Diet had the highest average SUCRA values (67.2%), followed by the DASH (62.4%) and the Mediterranean diet (57.4%).”
Many media organizations have consistently ranked the Mediterranean and DASH diets highly, and this meta-analysis shows those rankings are right. But those media organizations have also often ranked The Paleo Diet low for health. Unfortunately, many people are confused about The Paleo Diet, partly because many bloggers have created their own twists on paleolithic eating that are not based on science. This meta-analysis shows that science ranks The Paleo Diet above Mediterranean and DASH at improving biomarkers of chronic disease. So, the media is as confused about healthy nutrition as many of their readers.
Other Important Results from the Meta-Analysis
Government Guidelines Are Not Very Good for You
A surprising result of this study was that diets based on government recommended dietary guidelines scored at just 48.5% on the SUCRA scale. In other words, feeding people a diet based on the official recommendations showed a low likelihood of improving the risk for chronic disease.
Likewise, the plant-based diet was ranked at 49.3%. The plant-based diet actually worsened HDL cholesterol (the good kind of cholesterol that can improve heart health and lower risk of cardiovascular disease).
Specific Foods Affect Health, Specific Macronutrient Ratios Do Not
The macronutrient composition of the diets had little correlation with almost all of the biomarkers. This means that, save for a few exceptions, if you focus purely on macros, for example by eating high-fat, low-fat, high-carb, or low-carb, there’s no evidence it’s going to have any impact on your risk for non-communicable diseases. In simpler terms, diets that focus only on high carb or low carb, high fat or low fat, high protein or low protein are not necessarily healthier for you. What matters is the specific foods you eat. You are what you eat. If you eat a healthy diet, like The Paleo Diet, this meta-analysis shows that your health should respond.
The Paleo Diet Is Anti-Inflammatory
The Paleo Diet was by far the most effective diet at reducing biomarkers of inflammation with a SUCRA score of 87%, reinforcing existing science that shows The Paleo Diet is a strongly anti-inflammatory diet. Inflammation is generally regarded as exacerbating most chronic illness including cardiovascular diseases. The DASH diet, which focuses on lowering blood pressure through foods lower in sodium and higher in potassium, magnesium, and calcium, came in second at 71.3%. The Mediterranean diet, which includes foods associated with inflammation like processed grains and legumes, earned a SUCRA score of 58.1%, showing that it is significantly less healthy for this condition.
Ranking The Paleo Diet by Biomarkers
It’s also important to point out that while The Paleo Diet was consistently near the top of all three biomarker groupings, it wasn’t at the top of all three. The Mediterranean diet topped the list for lipid profiles, though The Paleo Diet ranked very well for improving HDL cholesterol.
“The Paleo Diet was ranked among the top dietary patterns for several blood lipids, such as triglycerides and HDL cholesterol, and glycemic outcomes including fasting blood glucose and HbA1c.”
Likewise, The Paleo Diet was second in glycemic control at 65.2% just behind a low-carbohydrate, high-fat diet at 66.4%. This makes sense since The Paleo Diet is considered a low-carbohydrate, high-fat diet compared with the typical Western diet because we recommend reducing grains and refined sugars, which are major sources of carbohydrate.
Further, the researchers found that a few of the 68 studies they initially included in the meta-analysis may have been biased. When they removed those studies and reanalyzed the results, The Paleo Diet was shown to have additional benefits for stabilizing insulin levels, which is tied to avoiding or improving two common chronic diseases, diabetes and metabolic syndrome.
A Big Step in the Science of The Paleo Diet
When The Paleo Diet was first introduced in 2002, it was criticized by the nutrition community and lumped into the “fad diet” category because there were not yet any randomized clinical trials backing it. This felt like unfair criticism at the time because there simply had not been enough time to conduct those studies.
20 years after the introduction of The Paleo Diet, there are now more than 500 studies supporting The Paleo Diet. There is now enough research to conduct large-scale meta-analyses of The Paleo Diet, which is a major milestone in nutrition science and a validation of the work of Dr. Loren Cordain, S. Boyd Eaton, and other paleolithic nutrition researchers. This first, large-scale meta-analysis joins seven other meta-analysis studies in supporting the health claims of The Paleo Diet. This latest study illustrates how the science contradicts the media, backing The Paleo Diet as healthier than the Mediterranean and DASH diets, which are two of the diets most often recommended by dietitians.
Here at The Paleo Diet, we believe in the science of Dr. Cordain and his colleagues. We have always said that we follow the science. If the body of science says The Paleo Diet is wrong, we will change our recommendations, and we have done that over the past 20 years. With this important meta-analysis, we are happy to see the body of nutrition science validating Dr. Cordain and The Paleo Diet.
Download a summary of this article and the study: The Paleo Diet Is Healthier than Mediterranean and DASH Diets (2 meg pdf).