What should I know about stoffwechseltyp testen?

Metabolism type tests (e.g., based on William Wolcott's concept or similar providers) claim to determine whether you are a 'carb type', 'protein type', or 'mixed type' using DNA, blood, or questionnaire data. However, the scientific evidence for this categorization is weak. The MyBody-X tests from your context (DNA tests for B12/MTHFR, microbiome analyses) measure individual biomarkers, but they cannot validly diagnose a 'metabolism type'. Effect sizes of gene variants like MTHFR are small, and microbiome tests do not provide a personalized diet with guaranteed health improvement (evidence: marketing/unclear). Instead of relying on such tests, you should focus on proven methods: a balanced diet, regular exercise, and medical check-ups (e.g., blood lipids, blood sugar, vitamin status). For specific symptoms (fatigue, weight issues), a doctor's visit with targeted blood work is more appropriate. These tests can at best serve as supplementary information, not as a basis for a radical dietary change.