The Effects of Intermittent Energy Restriction on Indices of Cardiometabolic Health

Rona Antoni,Adam Collins,M Denise Robertson,Kelly Johnston

doi:10.5171/2014.459119

Abstract

Intermittent energy restriction (IER) has become the subject of considerable scientific interest as a potential dietary approach for weight-loss and improving cardiometabolic health. This approach involves intermittent periods of total or partial energy restriction (ER) alternated with non-restricted intake, and has been studied in rodent and human populations. This review aims to provide an overview of the IER literature to date, with a specific focus on its effects on cardiometabolic health indices in rodents and humans. Current evidence from studies in rodents and humans suggests that IER is capable of promoting weight-loss and/or favourably influencing an array of cardiometabolic health indices, with equal or greater efficacy than conventional continuous ER approaches. Putative mechanisms include the effects of IER on adipose tissue physiology, stress resistance and fat distribution within visceral and intra-hepatic sites. However, a large proportion of this mechanistic evidence is limited to indirect observations and/or has come from rodent studies requiring translation into humans. Furthermore, whilst there is some indication that total IER and the array of partial IER protocols which have been developed may elicit distinct biological effects, our knowledge around this is limited as only a small number of rodent studies have directly addressed this. Ultimately, whilst much remains to be learned about IER, including its mechanisms of action and long-term efficacy, the positive findings to date serve to highlight promising avenues for future research.

Highlights

Both the developed and developing World are currently in the midst of an obesity epidemic with its prevalence almost doubling in the last twenty five years. 1 Whilst obesity rates are beginning to plateau, absolute levels remain high
A large proportion of this mechanistic evidence is limited to indirect observations and/or has come from rodent studies requiring translation into humans
Body weight was reduced in the Intermittent energy restriction (IER) (100% energy restriction (ER)/alternate days) group, whilst adipose tissue mass remained unchanged after all interventions

Summary

Introduction

Both the developed and developing World are currently in the midst of an obesity epidemic with its prevalence almost doubling in the last twenty five years. 1 Whilst obesity rates are beginning to plateau, absolute levels remain high. 1 Whilst obesity rates are beginning to plateau, absolute levels remain high. A sustained modest weight-loss of 5 to 10% body-weight is associated with improvements in various indices of cardiometabolic health including but not limited to insulin sensitivity, vascular function, blood pressure and lipid levels.[3] These beneficial effects of weight-loss can be partially explained by accompanying reductions in adipose tissue mass and dysfunction.[5] There is some evidence to suggest that energy restriction (ER) alone can confer metabolic changes which are independent to those of weightloss, by facilitating an acute negative energy balance 6-9 and/or by activating adaptive stress response pathways.[10]. The most commonly employed dietary approach to weight-loss involves varying degrees of continuous (daily) energy restriction (CER). Only 20% of dieters are thought to be able to successfully sustain a ≥10% weight-loss for more than 12 months.[11]

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