warum nehme ich trotz sport und kaloriendefizit nicht ab — what does this mean exactly?

This question describes a common frustration: despite exercise and a calorie deficit, weight does not drop. It does not necessarily mean the basic principles are wrong, but rather that the body counteracts on multiple levels. First, metabolic adaptation occurs: the body lowers its basal metabolic rate in response to a deficit, often more than expected. Second, calorie tracking is notoriously inaccurate – exercise calories are overestimated, and food intake is underestimated. Third, hormonal factors like hypothyroidism, elevated cortisol (stress), or insulin resistance can impair fat oxidation. Water retention from muscle repair or inflammation can also mask fat loss. Genetic variants (e.g., in FTO, TCF7L2) have small effect sizes and do not single-handedly explain a plateau. A microbiome test may offer clues about gut flora, but its clinical relevance for weight loss is not yet well-established. The key point: a true calorie deficit will eventually lead to weight loss, but the timeline can be weeks or months. If stagnation persists beyond 4 weeks, a medical check-up is advisable to rule out underlying conditions. Consumer DNA tests provide risk hints, not diagnoses, and should not be overinterpreted.