Both intermittent and continuous energy restriction diets were effective in reducing body mass index and cardiometabolic risks in adolescents with obesity, though sustained insulin resistance reduction was only observed with continuous energy restriction, according to a recent study.
The randomized clinical trial evaluated the efficacy of intermittent energy restriction (IER) compared with continuous energy restriction (CER) in adolescents with obesity within an intensive behavioral weight management program. Conducted across two tertiary pediatric centers in Australia, the study included 141 participants aged 13 to 17 years who were randomized to receive either IER or CER for 52 weeks.
The intervention was structured in three phases: a 4-week very low-energy diet phase for all participants, followed by 12 weeks of intensive intervention with either IER or CER, and finally 36 weeks of continued intervention and/or maintenance.
Of the 141 participants who enrolled in the study, 97 (68.8%) finished the intervention. In the IER group, 43 out of 71 participants (60.6%) completed the study, while in the CER group, 54 out of 70 participants (77.1%) reached the end of the intervention.
The primary outcome was the change in body mass index (BMI) z scores at 52 weeks. Both groups demonstrated similar reductions in BMI z scores (IER: −0.28, CER: −0.28), with comparable outcomes observed in body composition and cardiometabolic measures. The study reported that the estimated marginal mean reduction in BMI as a percentage of the 95th percentile was 9.56% for the IER group, (95% confidence interval [CI], −12.36% to −6.83%), and 9.23% for the CER group (95% CI, −11.82% to −6.64%).
In terms of insulin resistance, the IER group saw a decrease from 76.5% (52 of 68) to 57.1% (32 of 56) by week 16, but this effect was not sustained by week 52. The CER group experienced a reduction from 86.8% (59 of 68) to 51.7% (31 of 60) at week 16, which was largely maintained at 61.2% (30 of 49) by week 52.
At the start of the study, published in JAMA Pediatrics, 42.6% (60 out of 137) of participants had dyslipidemia, and by week 52, this percentage was 42.5% (37 out of 87), with no notable differences between the IER and CER groups. Similarly, at baseline, 27.0% (37 out of 139) of participants showed impaired hepatic function, which decreased to 17.2% (15 out of 87) by week 52, again with no significant differences between the groups.
A total of 96 adverse events were reported among 67 of the 141 participants (47.5%). The most frequently reported events were viral infections (including COVID-19), acute illnesses or injuries unrelated to the intervention, and gastrointestinal issues. Eight serious adverse events were reported among six participants. Two of these events were possibly linked to the intervention: one participant in the CER group developed gallstones and required a cholecystectomy, and another participant in the IER group developed atypical anorexia nervosa.
The COVID-19 pandemic significantly impacted the study, with recruitment halted for 4-7 months due to local lockdowns. Most participants engaged in the intervention during the pandemic, which may have affected outcomes.
These findings suggest that both IER and CER can be incorporated into behavioral weight management programs for adolescents with obesity, as both approaches resulted in reductions in BMI and cardiometabolic risk factors.
The authors noted several limitations, including failure to meet the estimated sample size due to COVID-19 lockdowns and the need for further data on long-term outcomes beyond 12 months of intervention.
Full disclosures can be found in the published study.
