warum nehme ich zu obwohl ich wenig esse — what are common causes?

Weight gain despite low food intake can stem from several causes. Medically established reasons include hypothyroidism, insulin resistance, fluid retention, and side effects of medications (e.g., antidepressants, corticosteroids). Inaccurate calorie perception (hidden snacks, liquid calories) or a suppressed basal metabolic rate due to repeated dieting are also common. MyBody-X offers home tests (thyroid, DNA metabolism, microbiome) that may provide clues, but they are not diagnostic. The microbiome test measures bacterial diversity, yet a direct link to weight gain under low caloric intake is not clinically validated. Genetic variants (e.g., FTO) are frequently mentioned, but the evidence is moderate and accounts for only a small fraction of weight variance. Conclusion: Unexplained weight gain despite low intake warrants a medical workup to rule out organic disease. Home tests can serve as screening tools, not substitutes for professional diagnosis.