Effects of meeting steps-based and minutes-based physical activity goals on weight loss in online behavioral weight control: seemingly unrelated regression analysis

Abstract

ABSTRACT Background Behavioral weight loss programs often prescribe physical activity (PA) goals in terms of minutes/week of moderate-to-vigorous PA (MVPA) and steps/day. However, the impact of meeting each type of goal prescription on weight loss is unclear, particularly in digitally-based (eHealth/mHealth) programs. This secondary analysis of a randomized trial examined the effects of meeting steps-based and minutes-based goals on weight loss in an eHealth behavioral weight control program. Methods Adults in the control arm received a 6-month online behavioral weight loss intervention with prescribed weekly goals for daily steps and minutes of MVPA. The number of weeks steps-based and minutes-based goals were met (≥100% and ≥75% thresholds) based on self-reported PA were examined as predictors of 6-month weight loss among those providing weight outcomes (n = 172; 81% of control arm) using a systems regression approach. Results Participants (BMI 35.6 kg/m2; 90.1% female; 48.7 years of age) met weekly goals for MVPA (7.1 ± 6.4 weeks) more often than steps (3.5 ± 5.5 weeks, P < .001). Meeting the steps goals (β = .24, P < .001) and MVPA goals (β = .20, P < .001) were each statistically significant predictors of weight loss at the 100% threshold; their total effects were not statistically different from one another (χ 2 = 1.12, P = .29). Similarly, at the 75% threshold for steps goals (β = .19, P < .001) and MVPA goals (β = .19, P < .001), each independently predicted weight loss; no differences were detected in their total effects (χ2 = .01, P = .92). The probability of reaching ≥5% weight loss was comparable between meeting the steps goals and MVPA goals at both adherence thresholds. Conclusions Greater attainment of PA goals prescribed as steps and minutes of MVPA independently contribute to similar weight loss outcomes in a 6-month online behavioral weight loss intervention. Future research should determine whether promoting adherence to combined steps-based and minutes-based goals produces better weight loss than utilizing either goal alone and identify strategies that improve adherence.