Intermittent Versus Continuous Energy Restriction for Weight Loss and Metabolic Improvement: A Meta-Analysis and Systematic Review
Losing excess body weight is suggested to improve lipids, blood pressure, and glucose and to decrease the risk of cardiovascular disease and all-cause mortality. Continuous energy restriction (CER) involves daily energy restriction, whereas, Intermittent energy restriction (IER), also known as intermittent fasting includes periods of energy restriction (only for 2-3 d/wk) alternating with periods of unrestricted food intake.
The author Shasha and colleagues (January 2021) conducted a study titled “Intermittent Versus Continuous Energy Restriction for Weight Loss and Metabolic Improvement: A Meta-Analysis and Systematic Review” published in the Obesity Journal. The summary of the study is below:
Objective:
To investigate the effects of intermittent energy restriction (IER; only for 2-3 d/week) in comparison to continuous energy restriction (CER) on weight loss and metabolic outcomes in overweight or obese adults.
Method:
Databases that assessed weight loss and metabolic outcomes in IER and CER from the last decade to December 18, 2019, were collected for this randomized controlled trial (RCTs). RevMan version 5.3 software was used for conducting statistical analysis of the data. The effect sizes were expressed as weight mean differences and 95% CI.
Findings:
The study reports increased weight loss and a higher loss of fat-free mass (FFM) with short-term IER. Additionally, there was no difference in the percentage loss of FFM between both the groups. Weight loss decreases all-cause, cardiovascular, and cancer mortality. Additionally, sensitivity analysis showed a significant reduction in fasting insulin and HOMA-IR with IER. There was increased fasting insulin and HOMA-IR in statistical heterogeneity of effects across RCTs. Moreover, both diets demonstrated improvement in blood pressure, blood lipids, and waist circumference. Hence, both diets have similar metabolic improvements.
Limitation:
The authors acknowledge the following limitations due to which the results can’t be generalized. The limitations include high dropout rates, poor follow-up, enrollment of metabolically healthy individuals or well-controlled patients with T2DM and overweight or obesity, small sample sizes, different methods of measuring FM and FFM, high risk of performance bias, and other methodological problems.
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