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Abstract
This dissertation aimed to quantify the effects of randomized controlled trial (RCT) pediatric lifestyle interventions in treating childhood obesity. An additional aim of the dissertation was to examine the efficacy of the BRAVO!, the psychological need-support centered lifestyle intervention, on participants’ body composition and health-related fitness. A systematic review and meta-analysis were conducted to determine the efficacy of RCT pediatric lifestyle interventions in treating obesity among 11- to 17-year-old children. The primary outcome variables were body mass index (BMI), standardized BMI (BMIz), and waist circumference (WC). The results showed that pediatric lifestyle interventions were moderately effective in improving overweight and obese children’s BMI (-1.77 kg/m2, 95% CI [-2.65, -.88], p < .001), BMIz (-.30, 95% CI [-.44, -.17], p < .001), and WC (-3.72 cm, 95% CI [-5.59, -1.85], p < .001). In addition, moderation analyses suggested that lifestyle interventions were the most effective when participants were 13 to 15 years old and at the higher end of the obesity spectrum.
Furthermore, to test the efficacy of psychological need-support centered lifestyle intervention BRAVO!, an RCT was conducted with a sample of 40 pediatrician-referred participants (Mage = 13.20 ± 1.54) allocated to two parallel arms: 1) BRAVO! (n = 20) and b) “usual care” (n = 20). The 12-week BRAVO! consisted of 24 exercise sessions (twice/week, 60min/session) and family-based nutrition classes (once/week, 30min/session) and psychological need-support-centered behavior modification. The results showed that BRAVO! was efficacious in generating positive changes in participants’ BMI (F[1, 31] = 23.83, p < .001, ηp2 = .45), WC (F[1, 31] = 26.58, p < .001, ηp2 = .48), cardiovascular endurance (F[1,31] = 8.18, p = .008, ηp2 = .23), upper body (F[1, 31] = 28.33, p < .001, ηp2 = .50), and abdominal muscular strength/endurance (F[1, 31] = 28.34, p < .001, ηp2 = .45). The changes in cardiovascular endurance vanished over time, but the changes in BMI, WC, upper body muscular and abdominal muscular strength/endurance remained for a longer term. Conclusions: BRAVO! lifestyle program was efficacious in improving at-risk Hispanic children’s body composition and health-related fitness, behavioral, and psychological outcomes in the short and longer term.