was ist fettstoffwechsel — what does this mean exactly?

Fat metabolism (lipid metabolism) refers to the digestion, absorption, transport, storage, and utilization of fats in the body. It begins in the intestine where dietary fats are broken down by lipases and absorbed as chylomicrons. The liver is central, producing and clearing lipoproteins (VLDL, LDL, HDL). Fatty acids serve as energy sources, membrane components, and signaling precursors. Genetic variants (e.g., in FADS1, APOA1, APOE) can modestly influence these processes, but effect sizes are small. Direct-to-consumer tests like MyBody-X's DNA nutrition test analyze such SNPs, but clinical utility is limited because lifestyle factors (diet, exercise) dominate. Blood biomarkers (HDL, LDL, triglycerides) provide a snapshot but not a full diagnosis. Abnormal results warrant medical evaluation. In summary, fat metabolism is a well-understood physiological system; genetic insights from consumer tests are often overstated and should not replace standard medical advice.