warum nehme ich zu obwohl ich wenig esse — which blood markers matter?

Weight gain despite low caloric intake is a complex issue. Blood markers can offer clues but are not definitive. Key markers include: **Thyroid panel** (TSH, fT3, fT4) – hypothyroidism lowers metabolic rate. **Fasting insulin and HOMA-IR** – chronic hyperinsulinemia promotes fat storage. **Cortisol (diurnal profile)** – chronic stress elevates cortisol, increasing visceral fat. **Leptin and ghrelin** – leptin resistance impairs satiety. **Inflammatory markers (CRP, IL-6)** – low-grade inflammation disrupts metabolism. **Sex hormones (estradiol, testosterone)** – imbalances alter body composition. **HbA1c and oral glucose tolerance test** – early insulin resistance. **Vitamin D, ferritin, magnesium** – deficiencies can affect energy metabolism. Important: No single marker is diagnostic; interpretation requires clinical context. MyBody-X home tests can provide initial insights but do not replace medical evaluation. Evidence for these markers is graded as 'practice' (based on clinical experience and observational studies). Caveat: Weight gain is multifactorial – caloric balance, microbiome, genetics (e.g., FTO variants), medications, and psychological factors all contribute. A home test alone is insufficient.