Recent studies have identified the FTO genotype as accounting for about 2.7% of the variation in body mass index (BMI). This study aims to investigate the effect of FTO genotype on weight loss after physical activity, drug-based, or dietary interventions.

This was a systematic review and meta-analysis of randomized controlled trials in overweight or obese adults reporting reduction in BMI, body weight, or waist circumference by FTO genotype after drug-based, dietary, or physical interventions. The researchers used allele dose coding for genetic effects to fit the gene by treatment interactions to individual participant data. The primary outcome of the study was a change in adiposity or weight gain.

A total of 8 eligible randomized clinical trials, including 9,563 patients, were identified. The findings indicated no significant differences in body mass index, waist circumference, and body weight in response to weight loss intervention between FTO genotypes. The differential changes in BMI, body weight, and waist circumference by FTO genotype were not independently associated with the following factors: intervention length, ethnicity, intervention type, baseline BMI, age category, and sample size.

The research concluded that the carriage of the FTO minor allele was not associated with a differential change in adiposity after weight-loss interventions.