Understanding the Paleo Diet: What is a paleo diet?

October 2, 2025 •

4 min read

The Paleolithic era ended approximately 10,000 years ago, and proponents of the paleo diet believe that humans have not fully adapted to the modern foods introduced by agriculture. So, what is a paleo diet? It is an eating plan that mimics the diet of our hunter-gatherer ancestors, focusing on whole, unprocessed foods.

Quick Summary

The paleo diet focuses on foods available to hunter-gatherers, such as lean meats, fish, fruits, and vegetables, while excluding grains, legumes, and dairy. It aims to improve health by eliminating processed foods and aligning with ancestral eating patterns. Concerns exist regarding potential nutrient deficiencies and the long-term feasibility of this restrictive approach.

Key Points

Core Principle: The paleo diet is based on the food patterns of our hunter-gatherer ancestors, focusing on whole, unprocessed foods.
Allowed Foods: The diet emphasizes lean meats, fish, eggs, vegetables, fruits, nuts, seeds, and healthy fats like olive oil.
Forbidden Foods: Grains, legumes, dairy products, refined sugars, processed foods, and added salt are typically excluded.
Potential Benefits: Short-term studies show that paleo can lead to weight loss and improvements in certain metabolic markers, possibly due to eliminating processed foods.
Key Risks: Potential risks include nutritional deficiencies, especially calcium and fiber, and the cost and restrictive nature can make long-term adherence difficult.
Scientific Debate: The diet's premise is debated, as modern science shows human genetic adaptation has continued since the Paleolithic era.
Flexible Approach: Beginners can ease into the diet by following a flexible approach, such as eating paleo for most meals and allowing occasional non-paleo foods.

The Ancestral Eating Philosophy

At its core, the paleo diet is based on the idea that our bodies are best suited to the foods our hunter-gatherer ancestors ate during the Paleolithic era, a period spanning roughly 2.5 million to 10,000 years ago. Proponents argue that the agricultural revolution introduced grains, dairy, and legumes too recently in our evolutionary history for our genes to have fully adapted to them. This supposed 'genetic mismatch' is blamed for modern chronic diseases like obesity, diabetes, and heart disease. Therefore, the diet emphasizes eating whole foods that could be hunted, fished, or gathered, and avoiding processed foods, which were not available to early humans.

Foods to Enjoy on the Paleo Diet

Following a paleo eating plan means filling your plate with nutrient-dense, whole foods. The focus is on quality and variety, sourcing foods that are as close to their natural state as possible.

Key food groups include:

Lean meats: Prioritizing high-quality sources like grass-fed beef, chicken, pork, and bison is encouraged, as these are considered closer to what Paleolithic humans would have consumed.
Fish and seafood: Wild-caught fish, especially those rich in omega-3 fatty acids like salmon, mackerel, and tuna, are staples in the diet.
Fruits: A wide variety of fresh fruits provides natural sugars, vitamins, and fiber.
Vegetables: All non-starchy vegetables are encouraged and should form the bulk of your meals.
Nuts and seeds: These provide healthy fats and proteins, with options including almonds, walnuts, macadamia nuts, and pumpkin seeds.
Healthy oils: Oils derived from fruits and nuts, such as extra virgin olive oil, avocado oil, and coconut oil, are used for cooking and dressings.
Eggs: Pasture-raised or free-range eggs are a key protein source.

Foods to Avoid on the Paleo Diet

To adhere to the paleo philosophy, several modern food groups are eliminated or significantly restricted.

Foods excluded from the diet are:

Grains: This includes all types of cereal grains like wheat, oats, rye, barley, and rice.
Legumes: Beans, lentils, peas, peanuts, and soy are all off-limits.
Dairy products: Milk, cheese, yogurt, and other dairy items are generally avoided, though some variations may allow full-fat, grass-fed dairy.
Refined sugars and artificial sweeteners: Processed sugars, high-fructose corn syrup, soda, candy, and most packaged sweets are not allowed.
Processed foods: Anything highly processed, pre-packaged, or containing artificial ingredients is avoided.
Refined vegetable oils: Industrial oils like soybean, canola, and sunflower oil are excluded.
Added salt: Limiting salt intake is a common recommendation within the paleo diet.

Benefits, Risks, and Scientific Perspectives

The paleo diet's emphasis on whole foods and avoidance of processed items aligns with many healthy eating principles and offers potential benefits. Small, short-term studies have shown it can lead to weight loss, reduced waist circumference, and improvements in metabolic health markers like blood pressure, blood sugar, cholesterol, and triglycerides. These benefits may be largely attributed to the elimination of ultra-processed foods and added sugars.

However, the diet is not without risks and criticisms. Eliminating entire food groups can lead to nutrient deficiencies, particularly for calcium (from dairy) and fiber (from grains and legumes). Some experts argue that the diet's high intake of animal protein and saturated fat could pose long-term health risks, including potential kidney issues and cardiovascular concerns. Furthermore, archaeological evidence challenges the diet's historical premise, showing that some Paleolithic humans consumed wild grains and other plants. Evolutionary genetics also shows that human populations have adapted to digest dairy and grains in the thousands of years since the agricultural revolution.

Paleo Diet vs. Other Popular Diets


Feature	Paleo Diet	Mediterranean Diet	Standard American Diet
Core Philosophy	Mimics hunter-gatherer eating patterns.	Based on dietary habits of Mediterranean countries.	Characterized by high intake of processed foods and added sugars.
Grains	Excludes all grains.	Includes whole grains.	Often includes refined grains and cereals.
Legumes	Excludes legumes.	Includes legumes.	Includes legumes.
Dairy	Excludes most dairy.	Includes moderate amounts of dairy.	High intake of dairy products.
Healthy Fats	Emphasizes oils from fruits and nuts.	Emphasizes olive oil.	Often includes refined vegetable oils.
Meat	Emphasizes lean, grass-fed meats.	Emphasizes fish and poultry over red meat.	High intake of processed and red meats.
Processed Food	Strictly avoids all processed items.	Minimally processed foods.	High intake of highly processed foods.
Sustainability	Adherence is difficult for some due to restrictions and cost.	Generally easier to adhere to and more sustainable.	Typically not sustainable for long-term health.

Practical Tips for Starting Paleo

For those interested in trying a paleo approach, a gradual transition can be easier to sustain. Focus on incorporating more whole foods, increasing your intake of fruits and vegetables, and reducing your consumption of processed snacks and sugary drinks. Instead of eliminating entire food groups overnight, consider a more flexible approach where you eat paleo for a portion of your meals, as suggested by the diet's popularizer Loren Cordain. Meal prepping can be a helpful strategy to ensure you always have paleo-friendly meals and snacks on hand, making it easier to avoid non-compliant foods. Remember to prioritize organic and grass-fed options when possible, though conventional is still an option.

Conclusion

Ultimately, the paleo diet provides a compelling framework for eating based on whole, unprocessed foods and eliminating the junk food common in modern diets. While the long-term health benefits remain under-researched compared to other diets like the Mediterranean plan, the focus on fresh, nutrient-dense ingredients is a positive step for many. However, its restrictive nature and potential for nutrient deficiencies require careful consideration. Anyone considering a significant dietary change should consult a healthcare provider or a registered dietitian to ensure it aligns with their nutritional needs and health goals. For more in-depth information and research, the Mayo Clinic offers a comprehensive resource on the paleo diet.

Frequently Asked Questions

The paleo diet is based on the theory that human genes are not well-adjusted for the modern diet that emerged with farming, believing this 'genetic mismatch' contributes to chronic diseases.

Yes, short-term, small studies suggest the paleo diet can be effective for weight reduction, often because it eliminates processed foods and emphasizes high-protein, fiber-rich foods that increase satiety.

No, grains, including wheat, oats, and rice, are not allowed on the paleo diet. This is based on the premise that grains were not part of the ancestral diet.

Dairy products are excluded because they became widely available after the Paleolithic era with the domestication of animals for farming, and are not considered part of the ancestral diet.

Unprocessed potatoes, like baked potatoes, are generally considered paleo-friendly. However, processed potato products, like chips, are not allowed.

The main risks include potential nutrient deficiencies, specifically for calcium and fiber, due to the elimination of food groups like dairy, grains, and legumes. It can also be more expensive and difficult to maintain long-term.

The paleo diet is more restrictive, excluding grains and legumes, which are included in the Mediterranean diet. Both emphasize fresh, whole foods and healthy fats, but the Mediterranean diet is often considered more sustainable and easier to follow.