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

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

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].

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.

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.

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.