The Effects of Training Load During Dietary Intervention Upon Fat Loss: A Randomized Crossover Trial

ABSTRACT

Purpose: To date no studies have compared resistance training loading strategies combined with dietary intervention for fat loss. Methods: Thus, we performed a randomised crossover design comparing four weeks of heavier- (HL; ~80% 1RM) and lighter-load (LL; ~60% 1RM) resistance training, combined with calorie restriction and dietary guidance, including resistance trained participants (n=130; males=49, females=81). Both conditions performed low-volume, (single set of 9 exercises, 2x/week) effort matched (to momentary failure), but non-work-matched protocols. Testing was completed pre- and post-each intervention. Fat mass (kg) was the primary outcome, and a smallest effect size of interest (SESOI) was established at 3.3% loss of baseline bodyweight. Body fat percentage, lean mass, and strength (7-10RM) for chest press, leg press, and pull-down exercises were also measured. An 8-week washout period of traditional training with normal calorie interspersed each intervention. Results: Both interventions showed small statistically equivalent (within the SESOI) reductions in fat mass (HL: -0.67 kg [95%CI -0.91 to 0.42]; LL: -0.55 kg [95%CI -0.80 to -0.31]) which were also equivalent between conditions (HL – LL: -0.113 kg [95%CI -0.437 kg to 0.212 kg]). Changes in body fat percentage and lean mass were also minimal. Strength increases were small, similar between conditions, and within a previously determined SESOI for the population included (10.1%). Conclusions: Fat loss reductions are not impacted by resistance training load; both HL and LL produce similar, yet small, changes to body composition over a 4-week intervention. However, the maintenance of both lean mass and strength highlights the value of resistance training during dietary intervention.

KEYWORDS:

• Body composition
• muscle size
• resistance training
• strength
• supervision

Acknowledgments

The authors would like to acknowledge the research assistants and participants involved.

Disclosure statement

No potential conflict of interest was reported by the author(s).

IRB approval

Approval was granted by Health, Exercise and Sport Science ethics committee of Solent University, Southampton, UK.

Additional information

Funding

The author(s) reported there is no funding associated with the work featured in this article.