Intermittent Energy Restriction Is a Feasible, Effective, and Acceptable Intervention to Treat Adolescents with Obesity

Abstract

Background: Intermittent energy restriction (IER) is an effective obesity management strategy in adults.

Objective: The aim of this study was to investigate the feasibility, effectiveness, and acceptability of IER in adolescents (aged 12-17 y) with obesity [adult equivalent body mass index (BMI; kg/m2) ≥30].

Methods: During weeks 1-12 participants followed an IER dietary plan consisting of a very-low-energy diet (VLED) 3 d/wk (500-600 kcal/d) and an eating plan consistent with national dietary guidelines 4 d/wk. For weeks 13-26 participants chose to continue with 1-3 VLED d/wk or follow a prescriptive eating plan. Primary outcomes were feasibility and change in BMI expressed as a percentage of the 95th percentile (BMI %95th percentile) at 12 wk. Secondary outcomes were diet acceptability, body composition, cardiometabolic risk, vascular structure and function, quality of life (Pediatric Quality of Life Inventory), and eating behaviors [Dutch Eating Behavior Questionnaire (DEBQ-C)]. Linear mixed models were used to assess change in outcome measures.

Results: Of 45 adolescents invited to participate, 30 adolescents (mean ± SD age: 14.5 ± 1.4 y, female n = 25) with a median BMI of 34.9 (range: 27.7-52.4) were recruited. At 12 wk, 23 participants chose to continue with the VLED 2-3 d/wk, and 21 completed the study, indicating the feasibility of IER. Consistent with intention-to-treat analysis, BMI %95th percentile was reduced at 12 wk (difference in estimated marginal means ± SEMs: -5.6 ± 1.1, P < 0.001) and 26 wk (-5.1 ± 1.9, P = 0.013) compared with baseline. Plasma triglycerides were reduced at 26 wk from baseline (-0.33 ± 0.12 mmol/L, P = 0.03). Body fat percentage reduced between 12 and 26 wk (-1.57% ± 0.76%, P = 0.05). Carotid intima-media thickness (CIMT) (-0.06 ± 0.01 mm, P < 0.001) and flow-mediated dilation (absolute increase 0.44% ± 0.11%, P = 0.001) improved between baseline and 12 wk, with reduced CIMT maintained at 26 wk (P < 0.001). DEBQ-C and Pediatric Quality of Life Inventory scores improved throughout the intervention. Nineteen adolescents completed an acceptability interview, rating IER as easy and pleasant to follow (mean ± SD: +2.1 ± 1.2; +1.9 ± 1.2, respectively) on a Likert scale from -4 to +4.

Conclusion: IER is a feasible, effective, and acceptable intervention in adolescents with obesity achieving reductions in BMI and cardiovascular disease risk. This trial was registered at www.anzctr.org.au as ACTRN12618000200280.

Keywords: adolescent obesity; diet intervention; energy restriction; intermittent fasting; lifestyle intervention; weight loss; weight management.

Copyright © American Society for Nutrition 2019.