A recent study published in JAMA Network Open investigated the effectiveness of intermittent energy restriction (IER) compared to continuous energy restriction (CER) in adolescents with obesity and related metabolic complications. The multisite, 52-week randomized clinical trial, conducted across two tertiary pediatric centers in Australia, provides valuable insights into managing adolescent obesity, a growing global health concern.
The trial enrolled 141 adolescents aged 13-17 years with obesity and at least one associated complication. Participants were randomized to either IER or CER groups, both receiving intensive behavioral interventions delivered by a multidisciplinary team. The interventions consisted of three phases: a very low-energy diet (weeks 0-4), an intensive intervention (weeks 5-16), and a continued intervention and/or maintenance phase (weeks 17-52).
The primary outcome was the body mass index (BMI) z score at 52 weeks. Secondary outcomes included anthropometry, body composition, and cardiometabolic health assessments at baseline and 52 weeks. Researchers also monitored insulin resistance, dyslipidemia, and hepatic function.
Key Findings
At week 52, both groups demonstrated significant reductions in BMI z scores (IER: -0.28 [95% CI, -0.37 to -0.20]; CER: -0.28 [95% CI, -0.36 to -0.20]) and BMI expressed as a percentage of the 95th percentile (IER: -9.56 [95% CI, -12.36 to -6.83]; CER: -9.23 [95% CI, -11.82 to -6.64]). These results indicate that both IER and CER are effective in reducing BMI in adolescents with obesity.
Interestingly, the study revealed that both groups experienced a reduction in insulin resistance at week 16 (IER: 76.5% to 57.1%; CER: 86.8% to 57.1%). However, at week 52, this effect was sustained only in the CER group (86.7% to 61.2%). There were no significant differences between the groups regarding dyslipidemia or hepatic function.
Clinical Implications
"These 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," the researchers concluded. This is particularly relevant given the challenges in maintaining long-term adherence to restrictive diets.
The study's results offer clinicians an additional tool in their approach to managing adolescent obesity. By providing an alternative to continuous energy restriction, IER may improve patient adherence and overall outcomes in weight management programs. Further research is needed to explore the long-term effects of IER on cardiometabolic health and to identify which patients may benefit most from this approach.
