Intermittent Energy Restriction Attenuates the Loss of Fat Free Mass in Resistance Trained Individuals. A Randomized Controlled Trial

Abstract

There is a lack of research into how lean, resistance trained (RT) individuals respond to intermittent energy restricted diets. Therefore, we investigated body composition changes in RT-individuals during continuous energy restriction or intermittent restriction. A total of 27 males and females (25 ± 6.1 years; 169 ± 9.4 cm; 80 ± 15.6 kg) were randomized to a~25% caloric restricted diet Refeed (RF; n = 13) or Continuous group (CN; n = 14) in conjunction with 4-days/week resistance training for 7-weeks. RF implemented two consecutive days of elevated carbohydrate (CHO) intake, followed by 5-days of caloric restriction each week. CN adhered to a continuous 7-week caloric restriction. Body mass (BM), fat mass (FM), fat-free mass (FFM), dry fat-free mass (dFFM), and resting metabolic rate (RMR) were assessed pre/post-diet. Both groups significantly reduced BM (RF: baseline = 76.4 ± 15.6 kg, post-diet = 73.2 ± 13.8 kg, ∆3.2 kg; CN: baseline = 83.1 ± 15.4 kg, post-diet = 79.5 ± 15 kg, ∆3.6 kg) and FM (RF: baseline = 16.3 ± 4 kg, post-diet = 13.5 ± 3.6 kg, ∆2.8 kg; CN: baseline = 16.7 ± 4.5 kg, post-diet = 14.4 ± 4.9 kg, ∆2.3 kg) with no differences between groups. FFM (RF: baseline = 60.1 ± 13.8 kg, post-diet = 59.7 ± 13.0 kg, 0.4 kg; CN: baseline = 66.4 ± 15.2 kg, post-diet = 65.1 ± 15.2 kg, ∆1.3 kg p = 0.006), dFFM (RF: baseline = 18.7 ± 5.0 kg, post-diet = 18.5 ± 4.5 kg, ∆0.2 kg; CN: baseline =21.9 ± 5.7 kg, post-diet = 20.0 ± 5.7 kg, ∆1.9 kg), and RMR (RF: baseline = 1703 ± 294, post-diet = 1665 ± 270, ∆38 kcals; CN: baseline = 1867 ± 342, post-diet = 1789 ± 409, ∆78 kcals) were better maintained in the RF group. A 2-day carbohydrate refeed preserves FFM, dryFFM, and RMR during energy restriction compared to continuous energy restriction in RT-individuals.

The Comparison of the Effects between Continuous and Intermittent Energy Restriction in Short-Term Bodyweight Loss for Sedentary Population: A Randomized, Double-Blind, Controlled Trial

“…Therefore, it could be hypothesized that younger individuals with large bodyweight might achieve a better effect by the CER strategy. At the same time, it is more important to ensure daily energy deficiency than to rigidly restrict energy intake, which means that, for a day, physical activity needs to be increased if the calorie intake is excessive, which is consistent with evidence from previous studies [ 75 , 76 , 77 ].…”

Lean mass sparing in resistance-trained athletes during caloric restriction: the role of resistance training volume

“…Out of these 7 studies, 3 studies employed a longitudinal design (Dudgeon et al 2017;Stratton et al 2020), with one study providing no control group (Mitchell et al 2018): the other 4 studies were case studies (Pardue et al 2017;Kistler et al 2014;Robinson et al 2015;). One study (Campbell et al 2020) used mixed-sex groups. The average study duration was 18.19 weeks (Mdn = 18 weeks) and ranged between 4 weeks (Stratton et al 2020) and 8 months Pardue et al 2017).…”

Contrary to the Conclusions Stated in the Paper, Only Dry Fat-Free Mass Was Different between Groups upon Reanalysis. Comment on: “Intermittent Energy Restriction Attenuates the Loss of Fat-Free Mass in Resistance Trained Individuals. A Randomized Controlled Trial”

“…Campbell and colleagues recently published a randomised controlled trial investigating the effects of diets involving intermittent energy restriction versus continuous energy restriction on changes in body composition and resting metabolic rate (RMR) in resistance-trained adults [ 1 ]. Intermittent energy restriction is a topic of great interest to athletes, and this was a greatly needed study, because previous research in the realm of intermittent energy restriction has focused on populations with overweight or obesity.…”