What Isn't Paleo? A Guide to Foods to Avoid on the Paleo Diet

December 30, 2025 •

4 min read

The paleo diet is based on the idea that human genetics are ill-equipped to handle many foods introduced since the agricultural revolution roughly 10,000 years ago. So, what isn't paleo? The list of excluded items is often longer than many beginners assume and is crucial for anyone trying to follow this ancestral-based eating plan correctly.

Quick Summary

A comprehensive guide to identifying and avoiding foods that are not paleo, explaining why grains, dairy products, legumes, refined sugars, and processed oils are eliminated from this ancestral-based eating plan.

Key Points

Grains Are Excluded: All cereal grains, including wheat, rice, oats, and corn, are not paleo due to their introduction after the agricultural revolution and containing antinutrients.
No Legumes Allowed: Beans, lentils, peas, peanuts, and soy products are strictly excluded from the paleo diet, as they were not part of the ancestral diet and contain lectins.
Dairy is Not Paleo: Milk, cheese, yogurt, and other dairy products are typically excluded, as humans did not consume them during the Paleolithic era.
Processed Foods are Banned: Heavily processed items, including refined sugars, refined vegetable oils, and packaged snacks, are off-limits.
Avoid Refined Sugars: All forms of refined and added sugars, along with artificial sweeteners, are prohibited due to their modern origins and adverse health effects.
Limit Certain Fats: Modern vegetable oils like canola and soybean oil are not paleo, while healthy fats from nuts, seeds, and avocados are encouraged.

Grains, Legumes, and Dairy: The Agricultural-Era Exclusions

The most significant and foundational rule of the paleo diet is the exclusion of foods that became widely available with the advent of agriculture. This historical division is the primary reason why many modern staples are considered non-paleo.

Grains

All cereal grains are excluded from the paleo diet, including seemingly healthy options like whole grains. This category includes:

Wheat, including spelt and rye
Rice, including white, brown, and wild rice
Oats
Barley
Corn
Quinoa, while a seed, is often treated like a grain and avoided by strict paleo followers

The rationale behind this exclusion is that grains contain antinutrients like phytic acid and lectins, which can interfere with mineral absorption and gut health.

Legumes

Like grains, legumes were not a significant part of the hunter-gatherer diet. The entire category, which includes peanuts, is off-limits. Common legumes to avoid include:

All beans (black, pinto, kidney, etc.)
Lentils
Peas
Soy products, such as tofu, tempeh, and soy milk
Peanuts and peanut butter

The argument against legumes also involves their lectin and phytic acid content. While cooking can reduce lectins, the ancestral eating approach removes them entirely.

Dairy

For strict paleo adherents, dairy is a non-negotiable exclusion. The human diet only introduced dairy after the domestication of animals, long after the Paleolithic era. Dairy products to avoid include:

Milk (cow, goat, sheep)
Cheese
Yogurt
Butter (though some versions of paleo, like Primal, may allow grass-fed butter or ghee)
Ice cream

While some modified versions of paleo incorporate high-quality dairy, a strict interpretation avoids it entirely, citing potential issues with lactose and casein.

The Problem with Modern Processing

The paleo philosophy also emphasizes eating whole, unprocessed foods. This means a wide array of modern, store-bought products are not paleo, even if they seem innocent.

Processed and Refined Foods

Many packaged and convenience foods are loaded with ingredients that don't fit the paleo template. This includes:

Chips, crackers, and cookies
Packaged cereals
Salty snacks
Canned soups and processed meats
Convenience meals

Refined Sugars and Sweeteners

Refined sugar was completely absent from the Paleolithic diet and is known to contribute to various modern health issues. Foods and beverages with refined sugar are out, as are artificial sweeteners. Banned items include:

Sodas and fruit juices
Candy, cakes, and pastries
High-fructose corn syrup
Table sugar (sucrose)
Artificial sweeteners like aspartame and sucralose

Unhealthy Fats and Oils

The paleo diet advocates for healthy fats and oils while excluding highly processed vegetable and seed oils. These oils were not consumed by ancestors and have an unfavorable omega-6 to omega-3 ratio. Examples of oils to avoid include:

Canola oil
Soybean oil
Corn oil
Margarine and other trans fats

Alcohol

Most alcohol is also not paleo. Beer is made from grains, and liquor is heavily processed. While some followers make exceptions for specific drinks like wine or hard cider, a strict approach excludes most alcoholic beverages.

Comparison: Paleo vs. Non-Paleo Foods


Food Group	Paleo-Friendly Examples	Not-Paleo Examples
Grains	N/A (except for some strict exclusions like rice)	Wheat, rice, oats, bread, pasta, tortillas
Legumes	N/A	Beans, lentils, peas, peanuts, soy products
Dairy	N/A (some allow grass-fed ghee)	Milk, cheese, yogurt, butter, ice cream
Sweets	Small amounts of honey, maple syrup	Table sugar, high-fructose corn syrup, candy, soda
Fats	Avocado oil, olive oil, coconut oil	Canola oil, soybean oil, margarine
Meats	Lean, grass-fed meats, wild game	Processed meats like bacon, lunch meat, cured meats

Sneaky Non-Paleo Ingredients and Foods

Beyond the obvious categories, many modern foods contain hidden non-paleo ingredients. Learning to read labels is essential to successfully adhere to the diet. Always check for:

Added Sugars: Found in sauces, condiments, and dressings.
Soy Lecithin: Used as an emulsifier in many products.
Carrageenan: A thickening agent derived from seaweed but often not considered paleo.
Cornstarch: Used as a thickener in many processed items.
Preservatives and Additives: Any artificial flavors, colors, or preservatives are generally not paleo.

Conclusion: Understanding the 'Why' Behind What Isn't Paleo

Understanding what isn't paleo is the first and most critical step toward successfully following the diet. The exclusions are not arbitrary; they are based on the central principle of the diet: aligning your eating habits with those of our ancient ancestors by prioritizing whole, unprocessed foods. By removing grains, legumes, dairy, and heavily processed items, you can focus on a nutrient-dense diet rich in vegetables, fruits, lean proteins, nuts, and healthy fats. This approach, while restrictive, is designed to reduce inflammation and support overall health.

For more information on the diet's history and rationale, a helpful resource is the National Institutes of Health (NIH) bookshelf on the Paleolithic Diet: https://www.ncbi.nlm.nih.gov/books/NBK482457/.

Remember that some variations of the paleo diet exist, so personal tolerance and health goals should guide your specific choices. However, the list of foods covered in this guide represents the core exclusions common to nearly all paleo interpretations.

Frequently Asked Questions

Whole grains are excluded from the paleo diet because they are a product of agriculture, which began after the Paleolithic era. Proponents of the diet argue that human digestive systems are not optimized to process them, and they contain antinutrients like phytic acid and lectins.

No, peanut butter is not paleo. Peanuts are technically legumes, which are a major food group excluded from the diet. However, you can substitute with other nut butters made from almonds, cashews, or macadamia nuts, as long as they contain no added sugar or other non-paleo ingredients.

Yes, some versions of the paleo diet allow for small, limited amounts of natural sweeteners like honey or maple syrup, as they were available to early humans. However, they should be used sparingly, as the focus is on a low-sugar diet overall.

Instead of processed vegetable oils like canola or soybean oil, paleo-friendly oils include olive oil, coconut oil, avocado oil, and ghee (clarified butter), especially from grass-fed sources.

The paleo status of potatoes can vary depending on interpretation. Some strict versions exclude them due to their higher glycemic index and association with agriculture. Others, however, consider unprocessed, plain white potatoes to be acceptable.

Dairy products are excluded because they were not part of the Paleolithic human diet, and many people have trouble digesting lactose or are sensitive to casein. Some modified paleo diets may include high-quality, grass-fed, or fermented dairy.

Not necessarily. The paleo diet emphasizes eating whole, unprocessed foods. Many packaged snacks, even if they are organic, contain refined sugars, processed oils, or other non-paleo ingredients. Always check the ingredient list for compliance.