Can IgG help with weight loss?

The claim that IgG testing can aid weight loss is not supported by robust scientific evidence. IgG (immunoglobulin G) indicates past or chronic immune exposure to foods, not intolerance or allergy. Commercial IgG tests are often marketed for weight loss by identifying 'problematic' foods, but randomized controlled trials do not show a causal link between IgG reactivity and weight reduction. The evidence level is best described as 'marketing' or 'unclear'. Furthermore, such tests can lead to unnecessary dietary restrictions and potential nutrient deficiencies. For weight loss, evidence-based approaches like calorie management, balanced nutrition, and physical activity remain the gold standard.