warum nehme ich zu obwohl ich wenig esse — what symptoms are typical?

Gaining weight despite eating little is a multifactorial issue. The provided context highlights two relevant mechanisms: short-chain fatty acids (SCFAs) from fiber fermentation influence energy metabolism and satiety, and the rare leptin receptor variant rs2229616 (European frequency ~0.7%) is linked to impaired satiety and obesity. Typical symptoms of underlying metabolic or hormonal issues include persistent hunger, fatigue, cold intolerance (suggesting hypothyroidism), water retention, and carbohydrate cravings. However, evidence for direct clinical testing of SCFAs or this genetic variant is weak—most data come from mechanistic or population studies. Other common causes include thyroid dysfunction, medication side effects, insulin resistance, or psychological factors. A thorough medical evaluation (blood work, thyroid panel, metabolic markers) is recommended before attributing weight gain solely to genetics or microbiome.