MEDI CHECK Speicheltest: can a DNA test help?

The claim that a DNA test can determine your ideal diet type (low-carb vs. low-fat) is not supported by robust science. The evidence is weak and largely marketing-driven. While certain genetic variants, such as those in the FTO gene, are associated with a small increase in BMI (about 1–2 kg), the effect is modest and can be largely overridden by lifestyle factors like exercise. Other genes like PPARG, TCF7L2, or FADS1/2 have been linked to macronutrient metabolism, but study results are inconsistent, and effect sizes are too small to guide personalized diet recommendations. The complex interplay between genetics, microbiome, hormones, and environment cannot be reduced to a simple low-carb vs. low-fat dichotomy. To date, no randomized controlled trials demonstrate that genotype-based diet advice outperforms standard dietary counseling. Consumers should be cautious: these tests often promise simple answers where science has not yet provided clear guidance. A balanced, sustainable diet tailored to individual preferences and tolerances remains the more evidence-based approach.