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

Abstract

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.

Keywords: Cardiometabolic health; Continuous energy restriction; Inflammation; Intermittent energy restriction; Obesity.