Intermittent energy restriction ameliorates adipose tissue-associated inflammation in adults with obesity: A randomised controlled trial

Background & aims Although intermittent energy restriction (IER) seems to be as effective as continuous energy restriction (CER) for weight loss, there is still a need to determine the putative effect of this strategy upon the metabolic-inflammatory status. This study aimed to compare the effects of IER versus CER on cardiometabolic and inflammatory markers, over a 12-week period, in adults with obesity. Methods Twenty-eight Norwegian adults (20–55 years) with obesity [body mass index: 35.4 (3.7) kg/m2] from a clinical trial (NCT02169778) who completed a 12-weeks diet-induced weight loss as IER (n = 14) or CER (n = 14) were included in this study. Cardiometabolic, adipokines and inflammatory markers were evaluated at baseline and after the intervention. Plasma levels of 13 inflammatory cytokines and chemokines (IL-1β, IFN-α2, IFN-γ, TNF-α, MCP-1, IL-6, IL-8, IL-10, IL-12, IL-17A, IL-18, IL-23, and IL-33) and 4 adipokines (adiponectin, adipsin, leptin and resistin) were measured through multiplex bead-based flow cytometric immunoassays. Results Both interventions resulted in comparable reductions in fasting glucose and insulin concentrations, lipid profile biomarkers, and adipokines. There were significant differences in HOMA-IR between interventions, with a more pronounced reduction in the IER group (−3.7 vs −1.6, P = 0.040). Inflammatory cytokines and chemokines decreased significantly in the IER group only. Differences in the relative changes of IL-1β (−48.5 vs 58.2%, P = 0.011), IFN-γ (−53.2 vs 45.1%, P = 0.023), MCP-1 (−22.0 vs 17.4%, P = 0.023), IL-18 (−40.8 vs 10.1%, P = 0.019), IL-23 (−64.8 vs 44.0%, P = 0.011) and IL-33 (−53.4 vs 35.7%, P = 0.028) were statistically significant between groups, with improvements in the inflammatory profile in the IER group. Conclusions Our results suggest that a 12-weeks intermittent energy restriction, in comparison to a continuous energy strategy, could be advantageous to reduce inflammation associated with obesity, and consequently improve insulin resistance, regardless of the amount of weight loss. Registered under ClinicalTrials.gov Identifier no. NCT02169778.