Is IgG useful for Sport?

IgG food sensitivity tests are widely marketed to identify food intolerances, but they are not supported by major medical organizations (e.g., EAACI, AAAAI) for diagnosis. IgG antibodies reflect normal immune exposure to food proteins, not intolerance or allergy. In sports nutrition, there is no robust evidence that IgG-guided dietary elimination improves athletic performance, recovery, or gut health. The few available studies are small, mechanistic, or industry-funded, and results are inconsistent. Athletes may be better served by focusing on proven nutrition principles: adequate energy availability, macronutrient timing, hydration, and individual tolerance. Relying on IgG tests can lead to unnecessary food restrictions, potential nutrient deficiencies, and no performance gain. Evidence level: marketing/unclear. Caveat: No clinical utility for sport performance. If digestive issues persist, consult a sports dietitian or gastroenterologist rather than a commercial IgG test.