warum nehme ich nicht ab obwohl ich im kaloriendefizit bin — when to see a doctor?

If you aren't losing weight despite a perceived calorie deficit, several factors may be at play. Common issues include inaccurate calorie tracking (underestimating intake or overestimating expenditure) and metabolic adaptation, where the body lowers its resting energy expenditure. Medical conditions such as hypothyroidism, insulin resistance, PCOS, or side effects of medications (e.g., antidepressants) can also hinder weight loss. Genetic variants like FTO have a small effect (1–3 kg) and do not reliably predict diet response. You should see a doctor if weight loss stalls for weeks despite a consistent deficit and adequate physical activity, or if you experience fatigue, cold intolerance, mood changes, or hair loss. Recommended tests include thyroid panel (TSH, fT3, fT4), fasting glucose, HbA1c, and possibly cortisol. Consumer DNA or microbiome tests for weight loss lack strong evidence; IgG food intolerance panels are not clinically validated and should not replace medical evaluation.