Most athletes treat inflammation as the enemy. What if your own immune system is the source — and your diet is the trigger pulling the trigger?
For athletes managing autoimmune conditions — Hashimoto's thyroiditis, rheumatoid arthritis, psoriasis, inflammatory bowel disease — standard sports nutrition advice can actually worsen the underlying pathology. The Autoimmune Protocol (AIP), an elimination-phase extension of the Paleo framework, offers a structured approach to identifying food-based immune triggers and reducing systemic inflammatory burden.
---
What Is the AIP Diet and How Does It Differ from Standard Paleo?
The Paleo diet removes grains, legumes, and dairy. The AIP takes this further by temporarily eliminating nightshades (tomatoes, peppers, aubergine), eggs, nuts, seeds, alcohol, and all non-steroidal anti-inflammatory drugs (NSAIDs) during the elimination phase. The rationale centres on intestinal permeability — commonly called leaky gut.
Research by Fasano (2012, Annals of the New York Academy of Sciences) identified zonulin as a key regulator of tight-junction proteins (claudin, occludin, ZO-1). Elevated zonulin — triggered by gliadin in wheat and certain lectins in legumes and nightshades — increases paracellular permeability, allowing bacterial lipopolysaccharides (LPS) to translocate into the bloodstream. This LPS endotoxaemia drives TLR4 activation and systemic NF-κB-mediated inflammation, the same pathway that amplifies autoimmune flares.
---
The Elimination Phase: What Goes and Why
The AIP elimination phase typically lasts 30–90 days. Foods removed include all grains (including gluten-free grains like rice), legumes, dairy, eggs, nightshade vegetables, nuts, seeds, coffee, alcohol, and NSAIDs. The underlying logic is to remove all plausible intestinal permeability triggers simultaneously.
Athletes following AIP should not panic about carbohydrates. Root vegetables — sweet potato, cassava, taro, parsnip — provide adequate glycogen substrate. Fatty fish, pastured meats, organ meats, and a broad spectrum of non-nightshade vegetables form the dietary core. Bone broth and fermented vegetables (sauerkraut, kimchi without chilli) support mucosal healing via gelatin-derived glycine and probiotic diversity.
The critical performance concern is energy sufficiency. A 2016 study by Abbott and colleagues found that individuals on AIP consumed adequate protein (mean 1.8g/kg) but often undershot caloric targets during the first two weeks — a setup for low energy availability (LEA) that impairs immune function, HPA axis regulation, and training adaptation. Athletes must track intake proactively during AIP, not assume adequacy.
---
The Reintroduction Phase: Where the Real Science Happens
The AIP is not a permanent diet — it is a diagnostic elimination followed by a systematic reintroduction ladder. Foods are re-introduced one at a time, in a defined sequence (eggs first, then nuts/seeds, then nightshades, then legumes), with 5–7 days between each new food. Any return of symptoms — joint pain, skin changes, gut distress, fatigue, brain fog — identifies that food as a personal immune trigger.
Abbot and Switzer (2019, Inflammatory Bowel Diseases) conducted a prospective trial in 15 patients with active Crohn's disease and ulcerative colitis. After 11 weeks on AIP, clinical remission was achieved in 73% of participants, with significant reductions in Crohn's Disease Activity Index (CDAI) and Harvey-Bradshaw Index (HBI) scores. While this was a small pilot trial, it remains one of the few prospective clinical studies on the AIP protocol.
For athletes, the reintroduction phase is also where performance nutrition is rebuilt. Eggs, white rice, and nightshades may all reintroduce cleanly — broadening the athletic diet again without sacrificing the anti-inflammatory gains of the elimination phase.
---
Performance Considerations: Where AIP Helps and Where It Costs
The AIP's most tangible benefit for athletes is resolution of inflammatory fatigue — the persistent tiredness, elevated resting heart rate, and blunted training response characteristic of systemic inflammatory burden. When inflammation decreases, sleep quality improves, HRV rises, and training adaptations become more predictable.
The cost is dietary complexity. AIP requires significant food preparation, eliminates most convenient sports foods (bars, gels containing rice syrup, nut-based snacks), and demands caloric planning to prevent energy deficits. Athletes competing during an AIP elimination phase should reduce training volume by 20–30% and prioritise recovery metrics over performance targets.
There is no evidence that AIP improves performance in athletes without autoimmune or inflammatory conditions. It is a therapeutic dietary protocol, not a performance-enhancement strategy.
---
Athletes managing autoimmune conditions who want to calculate their macro targets during the AIP elimination phase — ensuring adequate carbohydrate from root vegetables, sufficient protein from animal sources, and caloric sufficiency — can use the free macro calculator at winsport.uk/tools/nutrition/paleo-diet-macros, which supports paleo-aligned dietary frameworks and AIP-compatible food categories.
Have you used the AIP protocol to manage inflammation around training? What was your experience with energy levels during the elimination phase?