Effects of 12 and 24 Weeks of Interdisciplinary Interventions on Health-Related Physical Fitness, Biochemical Markers, and Level of Food Processing in Overweight or Obese Adolescents: A Longitudinal Study

Background: The aim was to investigate the effects of 12 and 24 weeks of interdisciplinary interventions on health-related physical fitness, biochemical markers, and food processing levels in overweight or obese adolescents. Methods: Thirty-one adolescents completed 24 weeks of nutritional, psychoeducational, and physical activity interventions in addition to assessments and tests carried out before, at 12 weeks, and after 24 weeks. Results: There were increases in lean mass ( p = 0.003) and decreases in absolute and relative fat mass ( p < 0.001) for both sexes, as well as increases in flexibility on the right and left sides ( p < 0.001), maximum oxygen consumption ( p < 0.001) increased after the interventions, time spent in isometric exercises on the plank increased ( p > 0.05), total cholesterol after 12 weeks decreased ( p = 0.014), triglycerides were reduced ( p = 0.002), low-density lipoproteins were reduced ( p < 0.001), consumption of more processed foods after 24 weeks decreased ( p < 0.001), consumption of fresh foods in grams and kilocalories increased ( p < 0.001), and, in addition, the consumption of processed and ultra-processed foods was reduced ( p = 0.020). Conclusions: The 24-week interventions promoted superior benefits for adolescents’ physical, nutritional, and biochemical health, although the dropout rate was high (~50%).