Choosing between low-fat and low-carbohydrate diets for weight loss isn’t helped by taking patients’ genetics or insulin-secretion patterns into account, JAMA reports.
DIETFITS trial investigators randomized some 600 adults (BMI, 28–40) to 12 months of either low-fat or low-carbohydrate dieting. Researchers assessed the subjects’ genomes for the presence of three single-nucleotide polymorphisms associated with fat and carbohydrate metabolism; they also assessed the participants’ insulin-secretion patterns, measured in response to glucose challenge.
At 12 months, the groups’ mean weight loss didn’t differ by diet (each lost between 5 and 6 kg), nor did it differ by genetic makeup or insulin secretion.
Dr. Harlan Krumholz of NEJM Journal Watch Cardiology comments: “Even as this study failed to show a benefit of matching diet type to genotype, this signals a line of inquiry that is bound to grow as we seek to understand whether knowledge of our individual biology can lead to more precise recommendations about behavior and treatments. We should not assume the connection; we need to prove it.”