Motivational Interviewing to Promote Healthy Behaviours for Obesity Prevention in Young Adults: a Pilot Randomized Controlled Trial

Obesity is an established risk factor for many cancer types, including colon, endometrial, breast, and pancreatic. Obesity is complex and treatment is challenging. Thus, primary prevention of obesity is important. This is particularly important now since the COVID-19 pandemic had a profound impact on many obesity risk factors, such as chronic stress, overeating, and physical inactivity. Early adulthood is a key period in obesity development and a critical period for prevention interventions. Young adulthood is a period when Canadians may be highly amenable to healthy behaviour change, develop lifelong healthy behaviours and the primary prevention of obesity may be feasible. Interventions in early adulthood have the potential for primordial cancer prevention (i.e., stopping cancer risk factors before they develop). Despite the known impact of obesity on cancer, there have been few attempts to implement tailored population-based obesity prevention interventions. Obesity interventions must be flexible to address the complex causes of obesity and motivational interviewing may be a successful strategy.

Primary Objective:

1. To determine the feasibility (enrollment, retention, data completion, satisfaction) of a 6-month behavioural and educational intervention to promote healthy behaviours for obesity prevention among young adults.

Secondary objectives: 2. To determine the effects of the 6-month behavioural and educational intervention, compared to an educational intervention only, on change in BMI, health behaviours (nutrition, physical activity and sedentary time) and mental health (depression and anxiety) 3. To explore whether obesity risk stratification tools identify young adults who may be more successful in an obesity intervention.

Methods: A pilot randomized controlled trial will be conducted. Young adults (age 18-29) attending McMaster University will be recruited and randomized to either the intervention or control. The intervention will include individual motivational interviewing sessions (online or in-person) with a trained public health nurse plus educational materials (based on Canada's food guide and physical activity recommendations). The control group will receive educational materials only. The primary feasibility outcomes that will be evaluated as part of this pilot study include enrollment, retention (≥80%), data completion (≥80% of weights measured, and surveys completed), and participant satisfaction. Clinical outcomes will include weight change from baseline to 6-months, physical activity, nutrition risk, and mental health. Outcomes will be measured remotely using 'smart' electronic scales, activity trackers, and online questionnaires at baseline and every 2 months. Risk stratification will be applied at baseline to identify participants at high risk of obesity (e.g., due to family or personal history). Exit questionnaires will collect data on how participants felt about the study and cost analysis will be conducted.