The Paleo and GAPS (Gut and Psychology Syndrome) diets share some fundamental logical similarities, but they also have distinct differences, particularly in their approach and strictness.

Similarities in Logic
Both the Paleo and GAPS diets are based on the idea that many modern health issues are linked to a departure from an ancestral or “natural” human diet. The core logic of both diets centres on these points:
Elimination of Processed Foods: Both diets strictly eliminate processed foods, refined sugars, and artificial ingredients. The belief is that these modern additions to the food supply are inflammatory and contribute to poor health.
Avoidance of Grains and Legumes: Both diets completely remove grains (like wheat, rice, corn) but the Full GAPS diet does not remove all legumes (beans, lentils, peas). In the Paleo diet the rationale is that these foods contain anti-nutrients and other compounds that can irritate the gut and interfere with nutrient absorption.
Emphasis on Whole Foods: Both diets promote eating a diet rich in whole, nutrient-dense foods. This includes high-quality meats, fish, vegetables, and healthy fats.
Gut Health Focus: While the Paleo diet’s primary focus is on an evolutionary eating model, it still recognises the importance of gut health. The GAPS diet, however, is explicitly and intensely focused on healing the gut lining and restoring the gut microbiome. This is a central theme that drives all of its rules.
Focus on Nutrient-Dense Foods: Both diets prioritise foods that are rich in vitamins, minerals, and other beneficial compounds. They both encourage consuming foods like bone broth, which is considered a nutrient powerhouse for gut healing.

Areas of Complete Difference

While their logic aligns on a basic level, the GAPS diet can be considered a much stricter, more therapeutic version of the Paleo diet. The key differences lie in their specific rules, phases, and rationale.
The “Why” Behind the Diet: The Paleo diet is based on an evolutionary premise—eating what our Paleolithic ancestors ate. The GAPS diet, on the other hand, is a specific therapeutic protocol designed by Dr. Natasha Campbell-McBride to address “Gut and Psychology Syndrome,” a theory that links gut health to neurological and psychological conditions. Its purpose is not just to eat “naturally” but to actively heal the gut.
The Role of Starchy Vegetables: A standard Paleo diet often allows for starchy vegetables like potatoes, sweet potatoes, and yams. In contrast, the GAPS diet, especially in its initial stages, completely restricts all starchy plants. The logic is that complex carbohydrates are harder to digest and can feed harmful bacteria in an imbalanced gut.
Dairy Products: The Paleo diet generally excludes all dairy products, as they were not part of the ancestral diet. The GAPS diet, however, has a more nuanced approach. It initially eliminates all dairy but then slowly reintroduces specific, homemade fermented dairy products, such as yogurt, kefir, and ghee, as they are considered beneficial for gut health due to their probiotic content.
Structured Phases: The GAPS diet is not a “one-size-fits-all” eating plan; it is a meticulously structured protocol with multiple phases. It starts with a very restrictive “Introduction Diet” to calm and seal the gut lining, followed by a “Full GAPS Diet,” and finally a “Reintroduction” phase that can take a year or more. The Paleo diet, in contrast, is a more straightforward and less phased approach to eating.
Fermented Foods: While Paleo encourages fermented foods, they are an absolute cornerstone of the GAPS diet. The GAPS diet places an extreme emphasis on consuming homemade fermented foods like sauerkraut, kefir, and yogurt to actively repopulate the gut with beneficial bacteria.
Supplements: The GAPS diet, as a therapeutic protocol, often recommends specific supplements such as probiotics, cod liver oil, and digestive enzymes to support gut healing, a practice that is not a mandatory part of the standard Paleo diet.
In essence, while the Paleo diet and the GAPS diet both share a foundation of avoiding grains and processed foods, the GAPS diet is a highly specialised and more restrictive protocol with a singular, explicit goal: to heal and seal the gut lining to address a wide range of health issues.