warum nehme ich nicht ab trotz kaloriendefizit und sport — when to see a doctor?

Not losing weight despite a calorie deficit and exercise is frustrating but common. The most frequent cause is metabolic adaptation: prolonged restriction lowers resting energy expenditure. Additionally, tracking errors are widespread – people often underestimate calorie intake and overestimate exercise expenditure. Medical conditions like hypothyroidism, insulin resistance, PCOS, sleep apnea, or chronic stress (elevated cortisol) can impair fat loss. Certain medications (antidepressants, beta-blockers, corticosteroids) also contribute. You should see a doctor if the plateau persists for more than 4–6 weeks despite consistent adherence, or if you experience fatigue, hair loss, cold intolerance, irregular periods, or unexplained hunger. A physician can check thyroid function (TSH, fT3, fT4), fasting glucose, HbA1c, and possibly perform an oral glucose tolerance test. Consumer tests like MyBody-X (DNA, blood nutrient) may offer insights into genetic variants (e.g., FTO, MC4R) or micronutrient status, but their predictive power for weight loss is limited. Evidence for direct clinical utility in weight management is weak. In summary: if you have ruled out common tracking mistakes and lifestyle factors, and the stall continues, a medical evaluation is warranted to identify underlying metabolic or hormonal issues.