NutrigenomicsNutrigenomics, Overweight/Obesity and Weight Management Trial (NOW Trial)

The investigators hypothesize that compared to the provision of population-based lifestyle advice, providing DNA-based lifestyle advice via personalized nutrigenomics testing (PNT) to two distinct patient populations (Family Health Team patients receiving a lifestyle counselling intervention and transplant recipients) will lead to greater reductions in percent body fat. In addition, it will motivate them to adopt healthier dietary and physical activity habits through changes in attitudes and/or subjective norms and/or behavioural control, lead to greater fat loss (kg), increased percent lean mass and therefore improve health and quality of life outcomes for both patient populations. In addition, it is hypothesized that dietary strategies related to the intake of one or more dietary components of interest will mitigate post-transplant weight gain associated with three SNPs of interest.

This is a randomized clinical intervention trial involving a total of four groups of patients (n = 400). The two main patient groups include overweight or obese, stable transplant recipients and overweight or obese patients who are attending group counselling sessions at the East Elgin Family Health Team. Within these two main groups, there will be two sub-groups. Patients will be randomized to receive either PNT or standard nutrition intervention (SNI). Baseline data will be conducted consisting of a food frequency questionnaire and three-day food records using a validated multiple pass method. Bioelectrical Impedance Analysis (BIA) will be conducted to assess body composition and to derive percent body fat and lean mass. Weight and height will be measured using a weigh scale and stadiometer. Attitudes, subjective norms and behavioural control will be assessed using a Theory of Planned Behaviour Questionnaire. Those patients randomized to the PNT group will be instructed on a tailored nutrition care plan and physical activity recommendations based on their individual genetic profile. At the same time, the SNI group will be instructed on general nutrition and physical activity recommendations for weight loss, which include the use of dietary strategies from the standard tool ('Just the Basics') used by registered dietitians for transplant patients and the GLB program for patients attending the East Elgin Family Health Team sessions. Monthly email reminders or phone calls (depending on patient preference) will be sent to transplant recipients as a reminder of their nutrition and physical activity plan. Reminders of nutrition and physical activity goals for the Family Health Team participants are incorporated into the GLB program. Three months, six months and twelve months after baseline data collection and individual nutrition interventions, baseline data will be repeated. After the study is complete, participants in the SNI group will be offered a nutrigenomics report and consultation with a registered dietitian.

A paired t-test or repeated measures ANOVA will be used to assess within group change from baseline to each follow-up time point for: BMI, body fat, lean mass, and dietary intake. A repeated measures ANOVA will be used to test between group differences from baseline to each follow-up time point for: BMI, body fat, lean mass, and dietary intake. If significant mean differences are detected, a Tukey's post hoc test will be used to compare differences by group. Statistical significance will be determined by P < 0.05. General linear regression models will be used to assess interactions between each genotype of interest and each dietary component of interest on BMI and body composition from baseline to each follow-up time point.