warum nehme ich nicht ab trotz kaloriendefizit und sport — which blood markers matter?

The question of why weight loss stalls despite a calorie deficit and exercise is multifaceted. Beyond inaccuracies in tracking intake and expenditure, hormonal, metabolic, and genetic factors can impede progress. Blood markers can reveal hidden obstacles. Key markers include: thyroid panel (TSH, fT3, fT4) – hypothyroidism lowers basal metabolic rate; fasting insulin and HOMA-IR – insulin resistance blocks fat oxidation; cortisol (diurnal profile) – chronic stress promotes visceral fat storage; sex hormones like testosterone and SHBG – low free testosterone or high SHBG (as highlighted in the context) can reduce muscle mass and metabolic rate; vitamin D – deficiency is linked to weight loss resistance; inflammatory markers like CRP. The provided context specifically discusses testosterone and SHBG: elevated SHBG reduces free testosterone, potentially lowering metabolic rate. Additionally, the BDNF gene (from context) is involved in stress response, indirectly affecting cortisol levels. Evidence for these markers is moderate; no single test guarantees an answer. A comprehensive evaluation by a healthcare professional is recommended, as self-interpretation of lab results can be misleading.