Continuing Education Activity

The Paleolithic (Paleo) Diet emulates the dietary habits of early humans during the Paleolithic era, focusing on foods presumed to have been available through hunting and gathering. Modern adaptations of this diet emphasize the consumption of lean meats, fish, fruits, vegetables, nuts, and seeds—while excluding processed foods, grains, legumes, and dairy products. Proponents suggest that this dietary pattern aligns with human genetics and may offer health benefits such as improved blood sugar control, enhanced heart health, and weight loss. However, critics highlight potential challenges, including nutrient deficiencies due to the exclusion of certain food groups and the higher cost of sourcing organic and grass-fed products.

Participants in this course will gain a comprehensive understanding of the Paleo diet's historical foundations and modern interpretations. The curriculum covers the diet's potential health benefits and associated risks, equipping clinicians with the knowledge to provide evidence-based dietary guidance. Emphasis is placed on interprofessional collaboration among dietitians and other healthcare professionals to deliver personalized nutrition counseling. This team-based approach ensures patients receive balanced information, helping them make informed dietary choices that align with their health goals and nutritional needs.

Objectives:

• Differentiate between evidence-based benefits of the Paleo diet and common misconceptions regarding its effects on metabolic health.

• Screen patients for metabolic syndrome using established clinical criteria and assess dietary patterns for alignment with therapeutic goals.

• Implement individualized nutrition interventions incorporating Paleo principles while addressing potential nutrient deficiencies.

• Develop strategies for the interprofessional team to implement evidence-based guidance on the Paleo diet, ensuring collaborative and patient-centered dietary counseling.

Introduction

The Paleolithic (Paleo) diet is the modern interpretation of our hunter-gatherer ancestors' presumed dietary pattern during the Paleolithic era or "Stone Age," which began approximately 2.5 million years ago and ended around 10,000 BCE with the development of agriculture. During this era, humans evolved and underwent physiologic and anatomic adaptations that resulted in larger brains and reduced gastrointestinal tract size. These evolutionary changes were likely linked to diets prioritizing nutrient-dense, easily digestible foods. Increased brain size requires greater caloric and nutrient intake, and a smaller gut suggests a reduced capacity to digest fibrous plant material compared to earlier primates. Paleolithic Age people crafted stone tools to obtain, prepare, and cook the food they hunted or foraged. Cooking made food more digestible and allowed them to extract more energy from plants and animal products. They likely consumed an omnivorous diet, with variations depending on the climate, location, and season.[1]

The modern Paleo diet dates back to 1975, when gastroenterologist Walter L Voegtlin, MD, published The Stone Age Diet. In his book, Voegtlin proposed that humans are naturally adapted to a meat-heavy, low-carbohydrate diet, drawing from prevailing beliefs about the dietary habits of early hunter-gatherers. In 1985, S Boyd Eaton, MD, published a landmark paper in the New England Journal of Medicine, proposing that modern chronic diseases stem from a mismatch between contemporary diets and the foods humans evolved to eat. He argued that the diet of early hunter-gatherers is best suited to modern humans.[2][3] The Paleo diet gained widespread popularity in 2002 after Loren Cordain, PhD, published The Paleo Diet: Lose Weight and Get Healthy by Eating the Foods You Were Designed to Eat. Since then, the public has exhibited tremendous interest in this diet, known as the "caveman diet." Proponents contend that it aligns modern eating habits with the patterns of our ancestors, emphasizing foods to which humans are biologically suited.

Today's Paleo diet emphasizes whole foods such as vegetables, fruits, lean meats, nuts, fish, honey, and eggs and excludes grains, dairy products, legumes, added sugars, and processed foods. Individuals most frequently choose the Paleo diet for weight loss and perceived health benefits, although leading health organizations do not widely endorse it.[4] Clinicians should know the details of this diet to counsel patients about its potential benefits and risks and assist them in making informed decisions. 

Function

The last 2 centuries have seen a boom in industrialization and the rise of ultra-processed, low-cost, readily available foods with high caloric density to sustain a growing population. One consequence of consuming these foods is an increased prevalence of chronic conditions such as obesity, diabetes, hypertension, and cardiovascular disease. Scientists and laypeople are exploring solutions to reverse this trend, including adopting significant dietary and lifestyle changes. This quest for the "ideal" diet for health and longevity has brought to light several ancient or traditional cuisines, including Paleo, and those of Japan, India, and the Mediterranean, Nordic, and "Blue Zone" regions.

What is known about the diet of our Paleolithic ancestors? Scientists and anthropologists have reconstructed this diet using evidence from archaeological remains and studying modern hunter-gatherer communities. Early humans mainly ate uncultivated fruits, roots or tubers, vegetables, and sometimes honey, fish, and meats. They consumed varying amounts of fats and protein and, most likely, a diet high in plant fiber. Archaeological findings based on isotopic analysis show no universal dietary regimen in prehistoric times.[5] In Israel, fossil evidence from approximately 800,000 years ago reveals a varied, plant-based diet, including seeds, wild fruits and vegetables, nuts, and lesser amounts of meat and fish.[6] Examination of microfossils from Neanderthal dental calculus discovered in modern-day Iraq and Belgium demonstrates the consumption of several plants, including date palms, legumes, and seeds. Many of the identified plant starch remains reveal chemical changes consistent with cooking.[7] These archeological findings challenge the modern-day belief that prehistoric humans relied mainly on animal protein sources and raw foods.

About a dozen contemporary tribes across diverse regions and climates still follow a hunter-gatherer lifestyle. The most extensively researched of these groups is the Hadza tribe of Northern Tanzania. Their diet shares features of the Paleo diet, emphasizing whole, unprocessed foods while excluding grains, dairy, and processed products. They eat a diet high in fiber and protein and consume mainly tubers, berries, meat, baobab tree fruit, and honey. Modern cold-climate hunter-gatherers in northern regions such as Scandinavia rely heavily on fishing and obtain more calories from animal products than foragers in warmer climates.[8] 

Based on these findings, the Paleolithic era diet most likely consisted of the following foods:

• Plants: Tubers, seeds, nuts, flour made from pounded wild barley, fruits, berries, and flowers. Tubers are the enlarged structures that plants use to store nutrients; they are typically found underground and are similar to modern carrots, parsnips, and potatoes. 
• Animals: Large and small mammals (bison and rabbits), birds (ducks and wild chickens), reptiles (turtles), and foraged eggs likely comprised about 3% of the total energy consumed. 
• Fish and shellfish: Fresh and saltwater species were consumed primarily in coastal and river communities.
• Insects: Various insects (grasshoppers, beetles, locusts, and ants) and their products, including honey and honeycombs.[9]

Proponents of the modern Paleo diet assert that humans evolved to thrive on the foods available to prehistoric hunter-gatherers and that our physiology has not adapted to consuming agricultural commodities, including domesticated animals, dairy products, and farmed crops. However, this perspective overlooks that evolution is primarily driven by the need to ensure survival and reproduction rather than preventing chronic diseases or extending lifespan. Individuals choose today's Paleo diet for various reasons, including a desire for a "natural" or "ancestral" way of eating and perceived health benefits such as weight loss, improved energy, and reduced inflammation.[4] They often learn about the diet from social media influencers, popular literature, personal trainers, athletes, friends, and anecdotal success stories. Some functional medicine or integrative health practitioners and nutritionists recommend the Paleo diet, but there is limited support from mainstream medical societies. The American Heart Association and the American College of Lifestyle Medicine endorse dietary patterns emphasizing unrefined, plant-based foods and discourage highly processed foods and added sugars, but do not specifically recommend the Paleo diet.[4] 

The contemporary Paleo diet emphasizes consuming whole, unprocessed foods and avoiding added sugars and ultra-processed foods, as do the Mediterranean and Dietary Approaches to Stop Hypertension (DASH) diets. Individuals who follow the Paleo regimen may take a strict or modified approach. They generally eat vegetables, fruits, nuts, seeds, eggs, meats, and fish, excluding grains, legumes, dairy products, refined sugars, vegetable oils, and most packaged foods. Paleo guidelines typically omit modern cultivated potatoes, a type of tuber, due to their higher glycemic index and association with agriculture. Many Paleo adherents emphasize grass-fed, wild, or pasture-raised meats, which tend to have a healthier fat profile (higher in omega-3s and lower in omega-6s) than conventionally raised or processed meats but are often more expensive than the latter options. There is wide variation in the distribution of macronutrients. The diet is typically high in protein (19% to 35% of calories), moderate in fat (28% to 58% of calories), and relatively low in carbohydrates (22% to 40% of calories).[10] This excludes many low-cost, globally popular foods, including beans, lentils, peas, corn, wheat, rice, and products derived from them, such as plant-based milk substitutes. Individuals who follow a strict Paleo regime abstain from alcohol since products like beer are grain-based, and brewing and wine fermentation began during the agricultural era.

Clinical Significance

The Paleo diet, which excludes grains, dairy, and processed foods, has been studied for its potential benefits on metabolic syndrome and cardiovascular risk factors. The clinical evidence supporting it is less robust than other well-studied approaches, such as the Mediterranean and DASH diets.[11] Emphasizing whole, nutrient-dense foods and excluding high-glycemic and ultra-processed foods may benefit insulin resistance and inflammation. Some studies of Paleo adherents have demonstrated an improvement in the components of metabolic syndrome, with decreased waist circumference, triglycerides, blood pressure, and fasting glucose. Other investigators have noted decreased insulin secretion, increased insulin sensitivity, and improved lipid profiles in individuals following the Paleo diet.[12][13] 

Research by Whalen et al has explored the clinical implications of the Paleo and Mediterranean diets, particularly their associations with mortality, inflammation, and oxidative stress. They found that higher diet adherence was associated with lower all-cause mortality, cancer mortality, and cardiovascular disease mortality. Results from another study linked the diets to reduced inflammation and oxidative stress, showing lower biomarkers of systemic inflammation and oxidative stress among individuals who closely followed either of the 2 diets.[14][15] Research by Blomquist et al involved postmenopausal women who were overweight. Compared to the control diet, the Paleo diet was associated with decreased lipogenesis-promoting factors and improved triglyceride levels and insulin sensitivity.[16] 

The Paleo diet has risks and limitations. Like a vegan diet, eliminating dairy products may significantly reduce calcium and vitamin D intake and cause nutrient deficiencies. However, frequently consumed plant-based dairy substitutes popular with vegans, such as soy, almond, or oat beverages fortified with calcium and vitamin D, are excluded from the Paleo regimen. Some individuals who follow a Paleo diet eat large amounts of meat, which may adversely affect their cardiac health. Studies of the Paleo diet have shown a possible effect on the gut microbiome, leading to elevated serum trimethylamine-N-oxide (TMAO) levels. TMAO is a compound produced by gut flora from animal products and is associated with increased cardiovascular disease risk. One hypothesis for this alteration in the gut microbiome is that the Paleo diet lacks a variety of fiber components, including whole grains and legumes, that act as prebiotics to nourish beneficial gut bacteria and enable short-chain fatty acid production that reduces inflammation and improves gut barrier function.[17]

The evidence for the Paleo diet preventing obesity, diabetes, dyslipidemia, and cardiovascular disease is not well-established. Many studies lack a large sample size and long-term follow-up and include multiple diet variations, which may alter associations with health outcomes. A stricter Paleo diet definition has been proposed to standardize research, with criteria for 11 food groupings. A Paleo diet should include:

• Fruits
• Nuts
• Vegetables
• Fish
• Eggs
• Unprocessed lean meats

A Paleo diet should exclude or limit:

• Dairy products
• Cereals
• Grains
• Legumes
• Ultra-processed foods, including refined oils [18] 

Well-designed trials are needed to evaluate the Paleo diet's safety, efficacy, and long-term health effects.[19] Other factors not specific to the diet may contribute to its alleged benefits, such as consuming grass-fed and pastured rather than conventionally raised meats and avoiding ultra-processed foods.[10] Some individuals find the diet too restrictive or costly, making long-term adherence difficult and creating challenges in social dining situations. Due to a paucity of rigorous data, the American Heart Association and the American College of Lifestyle Medicine do not officially endorse the Paleo diet. Both organizations have voiced concerns about nutritional balance, long-term sustainability, and proof of its superiority over other diets. They recommend dietary patterns emphasizing unrefined, plant-based foods and limiting processed foods and added sugars. Most professional medical societies and advisory committees likewise advocate for consuming whole, plant-based foods and eating fewer processed products and less sugar while avoiding excess calories as the best strategy for promoting overall health and preventing obesity and other chronic medical conditions.[4] Clinicians need not endorse or oppose the Paleo diet but should be knowledgeable about it to engage in meaningful discussions with their patients about optimal nutrition.

Enhancing Healthcare Team Outcomes

The interprofessional team is crucial in counseling about health outcomes related to dietary patterns like the Paleo diet. Given the widespread impact of chronic conditions such as obesity, diabetes, and cardiovascular disease, caused partly by the rise of industrialization and the availability of ultra-processed foods, healthcare professionals and their patients are increasingly exploring dietary interventions to improve health. The Paleo diet, which emphasizes whole, unprocessed foods while excluding grains, dairy products, legumes, and processed foods, has been advocated for its potential to reduce inflammation and improve metabolic markers.

However, evidence for its clinical efficacy remains less robust than for the Mediterranean and DASH diets. Healthcare professionals from diverse disciplines, including physicians, nutritionists, dietitians, physician assistants, nurses, pharmacists, and behavioral health specialists, are well-positioned to collaborate and provide evidence-based guidance to patients considering the Paleo diet. They can educate patients on eating a healthy, varied diet high in fiber, fruits, vegetables, and lean protein sources while limiting sugars and processed foods. By understanding the Paleo diet's potential benefits and risks, the team can support patients in making informed, personalized food choices while addressing barriers to long-term adherence, such as social and financial constraints.