The NOW Trial: A Pragmatic Randomized Controlled Trial of Personalized, Genetic-Based Lifestyle Advice

Abstract

Background: The impact of nutrigenomics and lifestyle genomics interventions on health outcomes and behaviours remains controversial and under-explored. Objectives: To determine the short-term (3-month), moderate-term (6-month) and long-term (12-month) impact of providing personalized, genetic-based lifestyle information and advice on anthropometric measures, as well as dietary intake and adherence. Methods: The nutrigenomics, overweight/obesity and weight management trial (NOW Trial) is a pragmatic randomized controlled trial that was incorporated into the Group Lifestyle Balance™ (GLB) program (N=140). Inclusion criteria: overweight or obesity (BMI ≥ 25 kg/m2), ≥ 18 years of age, English-speaking, having access to internet at least one day per week, willing to undergo genetic testing, and not seeing another healthcare provider outside of the study for weight-loss advice. Exclusion criteria: Pregnancy and lactation. Twelve-month GLB weight management program groups were randomized 1:1 to receive either the standard GLB program or a modified nutrigenomics-based GLB program (GLB+NGx). Data collection occurred at baseline, 3-, 6- and 12-month follow-up. The predetermined primary outcome was change in body fat percentage (BFP). Dietary intake and adherence were secondary outcome measures. Statistical Analysis: Statistical tests conducted using SPSS (version 26.0) included: repeated measures analyses of variance (ANOVAs), split-plot ANOVAs, two-way ANOVAs, chi-square and Fisher’s exact tests and logistic regression. Key components of the Theory of Planned Behaviour were considered in the dietary intake analyses. Results: After 3- and 6-month follow-up, the GLB+NGx group improved (reduced) their BFP to a significantly greater extent (p\u3c0.05) than the standard GLB group. There were no statistically significant differences in BFP between groups after 12 months. Furthermore, the GLB+NGx group significantly reduced their total fat intake after 12 months; the standard GLB group did not. Dietary adherence to saturated fat and total fat recommendations were significantly (p\u3c0.05) greater in the GLB+NGx group compared to the standard GLB group at 12 months. Conclusion: Genetically-tailored lifestyle advice can lead to improvements in body composition over the short-term and moderate-term, and motivate long-term dietary changes and adherence to nutrition recommendations. Biological mechanisms may challenge long-term weight loss, even with genetically-tailored advice that motivates long-term dietary changes