GenomEats

What DNA can't tell you about diet

Why GenomEats does not offer MTHFR panels or genotype-matched weight-loss diets, and what trials like DIETFITS found when they tested the idea.

Published October 27, 2026 · Updated

The short answer

For a few traits, a single gene changes what a food does to you, and those are the ones GenomEats covers. Broader promises, such as a weight-loss diet matched to your DNA or supplement plans built on MTHFR, have not held up when tested. So GenomEats leaves them out.

Genotype-matched weight-loss diets

The DIETFITS trial at Stanford randomised 609 adults to a healthy low-fat or healthy low-carbohydrate diet for a year. Before starting, participants were genotyped for a three-variant pattern that had been marketed as predicting which diet would suit them. The genotype pattern did not predict who lost more weight on either diet, and neither did baseline insulin secretion.1

MTHFR panels

MTHFR variants are among the most heavily promoted results in consumer genetics, often packaged with supplement advice. The American College of Medical Genetics and Genomics recommends against routine MTHFR genotyping in the clinical evaluations where it is most often ordered, and states that MTHFR status does not change the standard folic acid advice for women who could become pregnant.2

How GenomEats picks a trait

  • The variant has a clear biological mechanism linking it to a specific food or nutrient.
  • The effect has been reproduced, or it is backed by clinical guidance.
  • Consumer DNA chips measure it reliably enough to report.
  • Knowing your result would change what you eat, drink or ask your doctor about.

A trait that fails any of these stays out, however popular it is.

Sources

  1. Gardner CD, Trepanowski JF, Del Gobbo LC, et al. Effect of low-fat vs low-carbohydrate diet on 12-month weight loss in overweight adults and the association with genotype pattern or insulin secretion: the DIETFITS randomized clinical trial. JAMA. 2018;319(7):667–679. pubmed.ncbi.nlm.nih.gov
  2. Hickey SE, Curry CJ, Toriello HV. ACMG practice guideline: lack of evidence for MTHFR polymorphism testing. Genet Med. 2013;15(2):153–156. doi.org

This page is educational and does not diagnose or treat any condition. Talk to a qualified clinician before making medical decisions based on a genetic result.