A randomised controlled trial to determine the effect of genotype-based personalised diet and physical activity advice for FTO genotype (rs9939609) delivered via email on healthy-eating motivation in young adults.

The prevalence of obesity continues to rise, and public health dietary recommendations are not being adhered to. The transition to higher education is a period of risk for weight gain in young adults and has been demonstrated as a good time to initiate behaviour change. A genotype-based personalised approach to dietary recommendations may motivate young adults to maintain or adopt positive dietary behaviours. The aim of the present study was to determine the efficacy of genotype-based personalised dietary and physical activity advice on healthy eating motivation in young adults. Participants were young adults (n = 153), aged 18-25 years. Baseline measures (participant characteristics, height, weight, body mass index (BMI), body fat percentage (BF%), healthy eating motivation and physical activity) were collected. Participants were genotyped for a SNP in the FTO gene (rs99396090) and randomly allocated (stratified for genotype) to three different groups (1. Genotype-based personalised advice: dietary and physical activity advice based on genotype, BMI, and reported physical activity, 2. Non-genotype-based personalised advice: dietary and physical activity advice based on BMI and reported physical activity 3. Control: no advice). A week after receipt of advice delivered via email, participants completed the healthy eating motivation questionnaire for a second time. Genotype-based personalised dietary advice did not affect healthy-eating motivation: when participants were analysed across the whole group (p = 0.417), when analysed according to those informed of a risk or non-risk-associated genotype (p = 0.287), or when analysed according to those with a BMI (> 25 kg/m2; p = 0.336) or BF% (male > 18%, female > 31%; p = 0.387) outside the healthy range. There was also no significant difference in healthy eating motivation at 1-week in the control or non-genotype-based advice groups. Genotype-based personalised advice for the prevention of obesity did not affect healthy eating motivation in this group of healthy, young adults.