Efficacy of ketogenic diet on body composition during resistance training in trained men: a randomized controlled trial

Abstract

BackgroundKetogenic diets (KD) have become a popular method of promoting weight loss. More recently, some have recommended that athletes adhere to ketogenic diets in order to optimize changes in body composition during training. This study evaluated the efficacy of an 8-week ketogenic diet (KD) during energy surplus and resistance training (RT) protocol on body composition in trained men.MethodsTwenty-four healthy men (age 30 ± 4.7 years; weight 76.7 ± 8.2 kg; height 174.3 ± 19.7 cm) performed an 8-week RT program. Participants were randomly assigned to a KD group (n = 9), non-KD group (n = 10, NKD), and control group (n = 5, CG) in hyperenergetic condition. Body composition changes were measured by dual energy X-ray absorptiometry (DXA). Compliance with the ketosis state was monitored by measuring urinary ketones weekly. Data were analyzed using a univariate, multivariate and repeated measures general linear model (GLM) statistics.ResultsThere was a significant reduction in fat mass (mean change, 95% CI; p-value; Cohen’s d effect size [ES]; − 0.8 [− 1.6, − 0.1] kg; p < 0.05; ES = − 0.46) and visceral adipose tissue (− 96.5 [− 159.0, − 34.0] g; p < 0.05; ES = − 0.84), while no significant changes were observed in the NKD and CG in fat mass (− 0,5 [− 1.2, 0.3] kg; p > 0.05; ES = − 0.17 and − 0,5 [− 2.4, 1.3] kg; p > 0.05; ES = − 0.12, respectively) or visceral adipose tissue (− 33.8 [− 90.4, 22.8]; p > 0.5; ES = − 0.17 and 1.7 [− 133.3, 136.7]; p > 0.05; ES = 0.01, respectively). No significant increases were observed in total body weight (− 0.9 [− 2.3, 0.6]; p > 0.05; ES = [− 0.18]) and muscle mass (− 0.1 [− 1.1,1.0]; p > 0,05; ES = − 0.04) in the KD group, but the NKD group showed increases in these parameters (0.9 [0.3, 1.5] kg; p < 0.05; ES = 0.18 and (1.3[0.5, 2.2] kg; p < 0,05; ES = 0.31, respectively). There were no changes neither in total body weight nor lean body mass (0.3 [− 1.2, 1.9]; p > 0.05; ES = 0.05 and 0.8 [− 0.4, 2.1]; p > 0.05; ES = 0.26, respectively) in the CG.ConclusionOur results suggest that a KD might be an alternative dietary approach to decrease fat mass and visceral adipose tissue without decreasing lean body mass; however, it might not be useful to increase muscle mass during positive energy balance in men undergoing RT for 8 weeks.

Effects of a ketogenic diet on body composition and strength in trained women

“…Our study aimed to evaluate the effect of a KD on body composition and strength following an 8-week RT program in strength-trained women. In light of results obtained in men under similar conditions [17], we hypothesized that a KD combined with RT would not alter FFM or strength-related parameters in strengthtrained women; the results obtained partially support our hypothesis. The use of reagent strips for the qualitative assessment of ketosis state was necessary in this study given the design and resource limitations.…”

“…Compared to endurance training, few studies have specifically investigated the effects of a KD on body composition and strength levels in resistance-trained subjects undertaking a resistance training (RT) program. It was previously reported that an eight-week RT program accompanied by a KD reduced fat mass (FM) and preserved fat-free mass (FFM) in trained men [17]. Similarly, other studies have shown favorable changes in body composition (↑ FFM and ↓ FM), strength and total testosterone [18].…”

Role of a Ketogenic Diet on Body Composition, Physical Health, Psychosocial Well-Being and Sports Performance in Athletes: A Scoping Review

“…While the current literature on athletic populations is inconclusive, it is important to acknowledge that several studies conducted on non-athletic individuals have demonstrated that Lean body mass (LBM) tends to be retained following a KD [ 21 , 22 , 23 ]. A study on 10 healthy men demonstrated that adherence to a KD over 6 weeks resulted in retention of LBM at week three followed by an increase at week six [ 23 ]. This may be due to the energy (29 kcal/kg/day) and protein intakes (2 g/kg/day) that were maintained by participants throughout the duration of this study [ 23 ].…”

“…A study on 10 healthy men demonstrated that adherence to a KD over 6 weeks resulted in retention of LBM at week three followed by an increase at week six [ 23 ]. This may be due to the energy (29 kcal/kg/day) and protein intakes (2 g/kg/day) that were maintained by participants throughout the duration of this study [ 23 ]. On the basis of these findings, it is suggested that future studies on athletic populations concentrate on protein intake or other supplementation (e.g., creatine or leucine) to ensure adequacy for LBM retention and/or increases when commencing a KD.…”

Ketogenic diets: Opportunities and limitations in practical application (LITERATURE REVIEW)

“…And not less important: at the beginning the patients report about drowsiness, dizziness, fatique, insomnia, light nauseas, constipation -all symptoms that were named "keto-flu" but they normally lessen (26). Important: patients can continue physical training despite of limitation of carbohydrates (176,177).…”