Intermittent Energy Restriction for Adolescents With Obesity
Authors: Lister Natalie B. , Baur Louise A. , House Eve T. , Alexander Shirley , Brown Justin , Collins Clare E. , Cowell Christopher T. , Day Kaitlin , Garnett Sarah P. , Gow Megan L. , Grunseit Alicia M. , Henderson Maddison , Inkster Mary-Kate , Kwok Cathy , Lang Sarah , Paxton Susan J. , Truby Helen , Varady Krista A. , Jebeile Hiba 
Published: August 2024

ImportanceAdolescent obesity requires effective and accessible treatment. Intensive dietary interventions have the potential to be used as adjunctive therapy for behavioral weight management.ObjectiveTo examine the effectiveness of 2 diet therapies, delivered as part of an intensive behavioral weight management intervention, in adolescents with metabolic complications associated with obesity.Design, Setting, and ParticipantsThis multisite, 52-week randomized clinical trial was conducted from January 31, 2018, to March 31, 2023, at 2 tertiary pediatric centers in Australia. Adolescents (aged 13-17 years) with obesity and 1 or more associated complications were included.InterventionsIntensive behavioral interventions, delivered by a multidisciplinary team, comparing intermittent energy restriction (IER) or continuous energy restriction (CER), with 3 phases: very low-energy diet (weeks 0-4), intensive intervention (weeks 5-16), and continued intervention and/or maintenance (weeks 17-52).Main Outcomes and MeasuresThe primary outcome was body mass index (BMI) z score at 52 weeks in the IER vs CER group. Anthropometry, body composition, and cardiometabolic health were assessed at baseline and 52 weeks. The BMI z score and percentiles were determined using Centers for Disease Control and Prevention growth charts. Insulin resistance, dyslipidemia, and elevated hepatic function were assessed.ResultsA total of 141 adolescents (median [IQR] age, 14.8 [12.9-17.9] years; 71 male [50.4%]) were enrolled, 71 in the IER group and 70 in the CER group, and 97 (68.8%) completed the intervention, 43 in the IER group and 54 in the CER group. At week 52, both groups had reduced BMI z scores (estimated marginal mean change, −0.28 [95% CI, −0.37 to −0.20] for IER and −0.28 [95% CI, −0.36 to −0.20] for CER) and reduced BMI expressed as a percentage of the 95th percentile (estimated marginal mean change, −9.56 [95% CI, −12.36 to −6.83] for IER and −9.23 [95% CI, −11.82 to −6.64] for CER). No differences were found in body composition or cardiometabolic outcomes between the groups. Both groups had a reduction in the occurrence of insulin resistance (from 52 of 68 [76.5%] to 32 of 56 [57.1%] in the IER group and from 59 of 68 [86.8%] to 31 of 60 [57.1%] in the CER group) at week 16; however, at week 52, this effect was observed in the CER group only (from 59 of 68 [86.7%] to 30 of 49 [61.2%]). The occurrence of dyslipidemia was unchanged between baseline and week 52 (60 of 137 [42.6%] and 37 of 87 [42.5%], respectively), with a small improvement in occurrence of impaired hepatic function tests (37 of 139 [27.0%] and 15 of 87 [17.2%], respectively). No differences were found in dyslipidemia or hepatic function between groups.Conclusions and RelevanceThese findings suggest that for adolescents with obesity-associated complications, IER can be incorporated into a behavioral weight management program, providing an option in addition to CER and offering participants more choice.Trial Registrationhttp://anzctr.org.au Identifier: ACTRN12617001630303