Beyond Calorie Tracking: A Pilot Trial of a Remotely Delivered Behavioral Weight Loss Intervention Using an Ad Libitum Plant-Based Diet (Preprint)

Differences in weight-loss outcomes among race-gender subgroups by behavioural intervention delivery mode: An analysis of the POWER trial

Prior in-person behavioural intervention studies have documented differential weight loss between men and women and by race, with Black women receiving the least benefit. Remotely delivered interventions are now commonplace, but few studies have compared outcomes by race-gender groups and delivery modality. We conducted a secondary analysis of POWER, a randomized trial (NCT00783315) designed to determine the effectiveness of 2 active, lifestyle-based, weight loss interventions (remote vs. in-person) compared to a control group. Participants with obesity and at least one cardiovascular disease risk factor (N = 415) were recruited in the Baltimore, MD area. Data from 233 white and 170 Black individuals were used for this analysis. Following an intention-to-treat approach, we compared the mean percent weight loss at 24 months by race-gender subgroups using repeated-measures, mixed-effects models. Everyone lost weight in the active interventions however, weight loss differed by race and gender. white and Black men had similar results for both interventions (white: in-person (-7.6%) remote (-7.4%); Black: in-person (-4.7%) remote (-4.4%)). In contrast, white women lost more weight with the in-person intervention (in-person (-7.2%) compared to the remote (-4.4%)), whereas Black women lost less weight in the in-person group compared to the remote intervention at 24 months (-2.0% vs. -3.0%, respectively; p for interaction <.001). We found differences between the effectiveness of the 2 weight loss interventions-in-person or remote-in white and Black women at 24 months. Future studies should consider intervention modality when designing weight loss interventions for women.

"Mindset Matters": Perseverance, a balanced approach and structured support as facilitators of whole foods plant-based adoption

Whole foods plant-based diets (WFPBD) show potential for preventing and addressing chronic diseases. However, concerns exist about their acceptability and feasibility. Research on firsthand WFPBD adoption experiences is limited but crucial for promoting dietary change. In a 12-week remotely delivered lifestyle modification program using an ad libitum WFPBD, twenty weight-loss seeking adults (ages 18-75) with overweight or obesity completed self-report surveys and semi-structured interviews via Zoom. The study aimed to explore: (1) experiences with WFPBD adoption; (2) factors that helped or hindered adherence; and (3) perceived salient benefits. Interviews were analyzed inductively through a conventional content analysis, and associations between variables examined with correlational analyses. Participants overall reported WFPBD adoption being a positive, new experience, with an equal number (30%) finding it easy/easier than expected as challenging. Key cited challenges included overwhelm, different eating habits in the household, and meal preparation. Key cited facilitators included adopting an incremental approach to dietary change, persisting after setbacks, and having simple go-to meals. Greater self-compassion and family support, and less sabotage from friends and family corresponded to greater dietary change (rs > 0.45, ps < .05). Participants valued accountability, structure, human support, nutrition psychoeducation and recipes in the program. Three categories emerged regarding perceived benefits of following the WFPBD: physical health benefits, improvements to eating habits, and greater perceived control/agency over health. Results indicate that future interventions should include psychological strategies alongside nutrition education to enhance self-efficacy, address household barriers, and combat feelings of overwhelm through sufficient structure, support, and meal preparation guidance. Messaging around WFPBD may benefit from discussing prevailing positive experiences with adoption, common benefits experienced, and options for an incremental approach given that feasibility and acceptability concerns may deter efforts.