Introduction: Diet interventions achieve modest weight loss in some adolescents only. Little is known about effectiveness of interventions in clinical settings. This study aimed to investigate the effectiveness of diet interventions in a tertiary clinic on weight loss in obese adolescents.
Methodology: 32 obese adolescents (20 girls; BMI 38.9±7.8kg/m2) aged 12-18years attended a tertiary clinic between February 2014 and June 2015. Structured dietary advice was given according to preference for a dietary intervention: very-low-energy diet (VLED); intermittent fasting (FAST); increased protein (PRO); low carbohydrate (CHO). Anthropometry (weight, height, BMI and waist circumference) and blood pressure were measured at each visit.
Results: Initial diet choices were: VLED n=11; FAST n=10; PRO n=9; and CHO n=1. One patient chose a “healthy diet” instead of a structured diet plan. After commencement 10 adolescents changed to a different diet, resulting in: VLED n=7; FAST n=6; PRO n=17; “healthy diet” n=2. The “healthy diet” and CHO patients were excluded from analysis due to small sample sizes. Time between first and final visit ranged from 2-56 weeks (2-13 visits). Mean weight change grouped by initial diet was: VLED +1.0±4.9; FAST +1.6±5.1; and PRO -5.1±7.5kg. Weight (p=0.03) and SBP (p=0.04) were significantly lower following PRO compared to FAST group when analysed according to initial diet. There were no significant differences in any outcomes when grouped by final diet, and no effect of changing diets on outcomes compared to not changing. A greater number of visits was associated with greater weight loss (r=-0.38, p=0.03) and greater reduction in BMI (r=-0.42, p=0.02).
Conclusion: Initial diet preference predicted weight loss and weight loss was related to the number of visits, suggesting intensive interventions improves weight loss outcomes in obese adolescents. The type of diet at completion of clinic did not affect outcomes.