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Background: Ketogenic 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. Methods: Twenty-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. Results: There 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. Conclusion: Our 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.
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R E S E A R C H A R T I C L E Open Access
Efficacy of ketogenic diet on body
composition during resistance training in
trained men: a randomized controlled trial
Salvador Vargas
1,2*
, Ramón Romance
2
, Jorge L. Petro
3
, Diego A. Bonilla
3,4
, Ismael Galancho
5
, Sergio Espinar
5
,
Richard B. Kreider
6
and Javier Benítez-Porres
2
Abstract
Background: Ketogenic 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.
Methods: Twenty-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.
Results: There was a significant reduction in fat mass (mean change, 95% CI; p-value; Cohens 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.
Conclusion: Our 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.
Keywords: Hypertrophy, Ketosis, High-fat diet, Fat distribution, Bodybuilding
* Correspondence: salvadorvargasmolina@gmail.com
1
EADE-University of Wales Trinity Saint David, Málaga, Spain
2
Human Kinetics and Body Composition Laboratory, Faculty of Education
Sciences, University of Málaga, Málaga, Spain
Full list of author information is available at the end of the article
© The Author(s). 2018 Open Access This article is distributed under the terms of the Creative Commons Attribution 4.0
International License (http://creativecommons.org/licenses/by/4.0/), which permits unrestricted use, distribution, and
reproduction in any medium, provided you give appropriate credit to the original author(s) and the source, provide a link to
the Creative Commons license, and indicate if changes were made. The Creative Commons Public Domain Dedication waiver
(http://creativecommons.org/publicdomain/zero/1.0/) applies to the data made available in this article, unless otherwise stated.
Vargas et al. Journal of the International Society of Sports Nutrition (2018) 15:31
https://doi.org/10.1186/s12970-018-0236-9
Background
Macronutrient manipulation has become a key nutrition
component that, implemented in synergy with training,
seeks to improve physical appearance, performance and
human health. Among many dietary strategies that have
been adopted, ketogenic diet (KD) is a subtype of low-
carbohydrate and high-fat diet that needs to be planned
considering special dietary features (such as the propor-
tion of macronutrients) and physiological changes (ketosis
generation). In view of the foregoing, KD should be
planned from an objective perspective, checking for any
increase in circulating ketone bodies (KB), a distinctive
marker of physiological/nutritional ketosis. Main KB
(acetate, acetone, and β-hydroxybutyrate) are produced in
the liver under low-carbohydrate availability conditions,
acting as an alternative energy source for peripheral tissue,
such as skeletal muscle, brain and heart [1]. To achieve a
state of ketosis through a KD, carbohydrate intake should
be reduced to a maximum of around 50 g per day, or 10%
of total caloric intake during the day, while protein intake
is moderate or high (e.g. 1.2 to 1.5 gkg
1
d
1
).
Remaining energy intake is predominantly from fats (60
to 80%), depending on the degree of displacement of car-
bohydrates and proteins [2].
Under normal conditions (with no KD diet or long
fasting periods), the circulating KB values (β-hydroxybu-
tyrate being the primary KB) are very low (<3 mmolL
1
); however, during physiological ketosis, as a result of
the KD, ketonemia can reach maximum levels of 7
8 mmolL
1
with no significant changes in blood pH [3].
At this point, it is important to clarify the difference be-
tween physiological ketosis and diabetic ketoacidosis,
where the concentration of KB in the blood can exceed
20 mmolL
1
, with a significant reduction in blood pH.
In healthy population, the circulating KB values do not
exceed 8 mmolL
1
, because the central nervous sys-
tem uses these molecules efficiently as a source of en-
ergy, instead of glucose [4].
Several studies have focused on the effects of KDs on
reducing body mass [5,6], on improving health condi-
tions, or as part of managing certain pathologies such as
type 2 diabetes mellitus [7,8], nervous system disorders
such as epilepsy [911], and in different types/stages of
cancer [1216]. Currently, there is some controversy
surrounding the advantages or disadvantages of KD for
sports performance. It has been argued, on the one
hand, that there are beneficial effects associated with the
reduction of total body mass and body fat, a higher rate
of fat oxidation, lower glucose oxidation and a reduction
in the rate of muscle glycogen utilization during physical
exertion, which represents an advantage in resistance
exercise [17]. On the other hand, physiological mecha-
nisms have been cited that may limit performance in re-
sistance training due to central fatigue, possibly because
of increased circulation of non-esterified fatty acids
which increases competition between these and trypto-
phan for albumin, resulting in an increase in free
tryptophan, which in turn causes a greater absorption by the
brain and subsequent augmentation of 5-hydroxytryptamine
(serotonin) synthesis, a neurotransmitter linked to the feel-
ing of lethargy and tiredness that may contribute to nerve
signal losses at central level and a decrease in motivation. In
addition, greater oxidation of amino acids can occur, which
increases the concentration of ammonia, contributing to
central fatigue [17]. In general, several authors have also
established that low-carbohydrate diets or KD do not seem
to be superior or offer advantages for resistance exercise,
compared with carbohydrate-rich diets [18,19].
With regards to the effects of KD combined with re-
sistance training (RT), such as muscle hypertrophy, there
is even less information available, when compared with
studies conducted on endurance-type performance. Even
though KD can provide adequate quantities of proteins
and calories necessary for muscle-protein synthesis in-
duced by RT, they induce a state similar to fasting,
prompting alterations in the metabolic pathways and
molecular processes relating to autophagy and stress re-
sistance [20], which consequently might hinder the
building of muscle mass.
Considering the need to study on the effects of KD in
resistance-trained subjects, the purpose of this study was
to determine if following a KD hypercaloric diet would
promote greater gains in fat free mass and fat loss dur-
ing a hypertrophic training period in resistance-trained
men. We hypothesized that a KD with caloric surplus in
combination with RT in trained men would have a posi-
tive impact in fat reduction, and it would benefit the
gains in lean body mass (LBM).
Methods
Study design
This study was conducted as a randomized, parallel arm,
controlled, prospective study. The independent variable
was nutritional intervention. The primary outcome vari-
ables were changes in body composition.
Participants
Figure 1presents a CONSORT diagram. Twenty-four
healthy men with more than 2 years of continuous ex-
perience in overload training participated in this
randomized controlled study (age = 30 ± 4.5 years;
height = 177 ± 3.4 cm; weight = 76.7 ± 5.7 kg; BMI = 23.4
± 2.2 kg/m
2
). All volunteered their participation and
agreed to complete the supervised training and diet pro-
tocols during the 8 weeks of the study. Subjects who had
consumed androgenic-anabolic steroids during the last 2
years or those who consumed any type of dietary supple-
ment during the study were excluded. The subjects were
Vargas et al. Journal of the International Society of Sports Nutrition (2018) 15:31 Page 2 of 9
advised of the potential risks of the experiment and
signed an informed consent form. The study was devel-
oped following the ethical guidelines of the Declaration
of Helsinki [21]. The investigation was developed in
Málaga (Spain). The first evaluation took place on
February 2017 and the second measurement on April of
the same year.
Procedures
Body composition
Total and regional body composition were estimated
using a Hologic QDR 4500 dual-energy x-ray absorpti-
ometry (DXA) scanner (Hologic Inc., Bedford, MA,
USA). Each subject was scanned by a certified techni-
cian, and the distinguished bone and soft tissue, edge
detection, and regional demarcations were done by com-
puter algorithms with APEX Software 3.0 (APEX
Corporation Software, Pittsburg, PA, USA). For each
scan, subjects wore sport clothes and were asked to re-
move all materials that could attenuate the X-ray beam,
including jewelry items. Calibration of the densitometer
was checked daily against standard calibration block
supplied by the manufacturer.
Abdominal region was delineated by an upper hori-
zontal border located at half of the distance between
acromions and external end of iliac crests, a lower
border determined by the external end of iliac crests,
and the lateral borders extending to the edge of the
abdominal soft tissue. All trunk tissue within this stan-
dardized height region was selected for analysis. To de-
termine intertester reliability, two different observers
selected the area for each subject manually.
Nutrition intervention
The participants were randomly assigned to a KD group
(n= 9), non-KD (NKD) (n= 10) group, and control group
(CG) (n= 5). Compliance with the ketosis state was moni-
tored by measuring urinary ketones weekly using reagent
strips (Ketostix, Bayer Vital GmbH, Leverkusen, Germany),
from week two to the end of the study in KD group.
Under the supervision of a registered dietitian, the sub-
jects were given a detailed questionnaire about their work
and sociocultural activities, as well as dietary preferences
in order to estimate the basal metabolic rate and physical
activity-related energy expenditure. Subjects were classi-
fied as active in their day-to-day lives, estimating total en-
ergy expenditure in line with the indications [22]. Once
energy expenditure was determined, together with their
weekly training load, a moderate energy surplus was
established for experimental groups, since it has been
noted that trained men do not require energy increases as
high as novice subjects [23,24]. To guarantee a hyperener-
getic condition, a daily energy intake of 39 kcal·kg
1
·d
1
was used in all subjects. To ensure a maximal anabolic
response, NKD group was given a protein intake of 2
gkg
1
d
1
, as it is recommended for building muscle
mass in trained subjects [2,22,25], while 25% of
total energy intake corresponded to fat and the
remaining calories were given in carbohydrates.
Macronutrient distribution for NKD group was about 55%
CHO; 20% PRO and 25% FAT. On the other hand, 42 g
total carbohydrates per day were administered to KD
group to ensure the ketosis state [26,27]. Protein intake
was 2 gkg
1
d
1
, and the remaining calories were given
in fat with a estimating of 3.2 gkg
1
d
1
.Macronutrient
distribution for KD group was about <10% CHO; 20%
PRO and 70% FAT. Ad libitum meal timing and frequency
throughout the day was allowed to improve dietary adher-
ence. Even though a specific number of meals per day is
not necessary, provided the daily energy intake is guaran-
teed [22], from 3 to 6 meals were recommended, with the
respective foods selected for the KD group.
Training protocol
During 8 weeks both KD and NKD groups completed
four sessions per week of a hypertrophy training proto-
col, organized into a 2-days upper- and 2-days
lower-limb, with 72 h of rest between sessions to en-
courage recovery [28] (Fig. 2).
Participants were experienced in overload training and
used to different nutritional strategies; therefore, no
familiarization session was necessary. Moderate to high
loads were used to encourage mechanical tension [29].
Rest between sets lasted 3 min, so that volume did not
decline [30,31]. Cadences were explosive in the concen-
tric activation, and 3 s long during the eccentric contrac-
tion to generate more muscle damage [29,32]. Two
weekly stimuli were provided for each muscle group in
order to optimize the final results [33]. Push and pull
exercises were interspersed for better recovery [34]. Sub-
jects from both groups were asked to increase loads as
long as they exceeded repetition rates and had no error
technique. During the intervention, all participants were
Fig. 1 CONSORT diagram
Vargas et al. Journal of the International Society of Sports Nutrition (2018) 15:31 Page 3 of 9
monitored by an RT specialist who supervised and
checked the load at each training session, and made the
relevant adjustments when was necessary. Meanwhile,
men in control group were asked to maintain their
current level of physical activity during the study.
Statistical analysis
Descriptive statistics tests were applied (mean and
standard deviation, SD). Data were analyzed using a uni-
variate, multivariate and repeated measures general lin-
ear model (GLM), with two levels by time (pre- and
post-test) and considering groups (KD, NKD and CG) as
inter-subjects factor. WilksLambda multivariate tests
are reported to describe overall effects of related vari-
ables analyzed. Greenhouse-Geisser univariate tests with
least significant difference and post-hoc comparisons
(Bonferroni correction) are presented for individual
variables analyzed. Partial eta squared effect sizes (ηp
2
)
were also reported on select variables as an indicator of
effect size (ES) of the repeated measures GLM. An Eta
squared around 0.02 was considered small, 0.13 medium,
and 0.26 large [35]. Furthermore, one-way analysis of
variance (ANOVA), with a 95.0% confidence level and
Bonferroni post-hoc correction, as is recommended for
these studies [36,37], was performed to detect
between-group differences in the Δchanges (post-test
pre-test). In addition, ES calculation was done with
Cohensd, as a standardized measurement based on SD
differences; while d = 0.2 was considered a small effect,
d = 0.5 was a medium effect and d = 0.8 was a large ef-
fect, which is used as a guide for substantive signifi-
cance. The normal Gaussian distribution of the data was
verified by the Shapiro-Wilk test. Mean changes with
95% CIs completely above or below baseline are consid-
ered significant changes from baseline. These statistical
analyses were performed with licensed Statistical Pack-
age for the Social Sciences (SPSS) software (SPSS 24.0,
SPSS Inc., Chicago, USA) and GraphPad software
(GraphPad Prism 7.03, California, USA).
Results
Baseline characteristics
A total number of 26 individuals met initial screening
criteria and consented to participate in the study (Fig. 1).
Two participants did not enter into ketosis state and
were excluded from the study, which left nine men for
analysis in KD group. Statistical analyses were performed
on 24 individuals. Descriptive statistics with baseline
characteristics are summarized, by groups in Table 1.
Body composition
The statistical results before and after the intervention
for total body weight (BW) and body composition; fat
mass (FM), visceral adipose tissue (VAT), and LBM are
shown in Table 2. Multivariate analysis showed signifi-
cant overall WilksLambda in time interaction (p=
Fig. 2 Overview of training protocol. WK: Workout (microcycle); UL: Upper-Limb; LL: Lower-Limb; R: Rest; 30X: 3 s of eccentric contraction and
explosive movement during concentric activity
Vargas et al. Journal of the International Society of Sports Nutrition (2018) 15:31 Page 4 of 9
0.031; with a large effect size, ηp
2
= 0.36) and in time x
group (p< 0.05; with a large effect size, ηp
2
= 0.264). On
the other hand, univariate analysis revealed significant
differences in time x group interaction between BW, and
LBM (p< 0.05), with a large effect size for BW (ηp
2
>
0.36); however, no significant differences were found in
VAT. Significant differences were observed over time in
VAT and LBM, with medium effect size for both (ηp
2
=
0.20 and 0.23, respectively). No significant differences
were found after group interaction analysis of the study
variables.
According to the results by group, BW increased in
KD group (p< 0.05), but to a small size (ES = 0.18), with
no significant differences in the other groups (NKD and
CG). With regards to FM, only KD group showed a sig-
nificant reduction (p< 0.05), expressing a medium effect
(ES = 0.46). Similarly, VAT only decreased markedly in
the KD group (p< 0.05), showing a considered large
effect (ES = 0.84). Conversely, LBM showed a highly
significant increase (p< 0.05) with moderate effect (ES =
0.31) in the NKD group; however, although LBM de-
creased in the KD group, this did not represent a statis-
tically significant difference or significant effect (p> 0.05;
ES = 0.04).
These results suggest that KD group achieved a posi-
tive change in body composition, due to a decrease in
BW (0.9 [2.3, 0.6] kg; p> 0.05) with a reduction in
FM (0.8 [1.6, 0.1] kg; p< 0.05) and accompanied by
a notably lower VAT (96.5 [159.0, 34.0] g; p< 0.05).
Regarding to LBM, an adequate carbohydrate intake
(non-ketogenic or conventional dietary approach), in
conjunction with a caloric surplus and a higher protein
intake, might be the most viable option for inducing
muscle hypertrophy after RT. This last was shown in this
study, where there was an increase in LBM (1.3 [0.5, 2.2]
kg; p< 0.05) in the NKD group, leading to an increase in
BW (0.9 [2.3, 0.6] kg; p< 0.05). Figure 3shows sig-
nificant differences in BW and LBM for NKD group;
and FM and VAT for KD group. Likewise, post-hoc ana-
lysis showed significant difference in the BW and LBM
between KD and NDK groups.
Discussion
The aim of this study was to determine the efficacy of
the KD when combined with an RT program on body
composition in trained subjects over a period of 8 weeks
of intervention.
We originally hypothesized that this intervention
would improve body composition due to a greater re-
duction in FM and VAT, and an increase in LBM. Our
hypothesis is supported by some lines of evidence, but
there are contradictory findings due to a lack of studies
analyzing the effects of the KD (with and without RT
protocol) on FM, VAT and muscle hypertrophy. Human
Table 1 Characteristics of participants at baseline
CG KD NKD p-value
Age (years) 31.6 ± 4.6 27.6 ± 4.2 27.1 ± 5.6 0.276
Height (cm) 179.9 ± 7.8 178.3 ± 4.0 178.3 ± 6.2 0.873
BW (kg) 78.9 ± 6.5 78.8 ± 7.8 74.6 ± 5.3 0.306
BMI (kgm
2
) 24.5 ± 1.7 24.4 ± 2.6 23.9 ± 1.6 0.793
FM (kg) 13.4 ± 4.5 12.0 ± 2.7 11.3 ± 2.6 0.499
LBM (kg) 65.6 ± 2.6 66.8 ± 6.8 63.2 ± 4.4 0.350
VAT (g) 757.7 ± 265.3 688.9 ± 125.4 658.0 ± 200.5 0.650
Data are means ± SD; p< 0.05 is considered significant; BW Total body weight,
BMI Body Mass Index, FM Fat mass, LBM Lean body mass, VAT Visceral
adipose tissue
Table 2 Results before and after the intervention for body composition by groups
Pre Post ES Interaction p-value (ηp
2
)
(Mean ± SD) (Mean ± SD)
BW CG 78.9 ± 6.5 79.2 ± 6.6 0.05 Time 0.830 (0.002)
KD 78.8 ± 7.8 77.4 ± 7.9 0.18 Group 0.437 (0.076)
NDK 74.6 ± 5.3 75.5 ± 4.9* 0.18 Time x Group 0.016 (0.327)
FM CG 13.4 ± 4.5 12.8 ± 4.0 0.12 Time 0.013 (0.258)
KD 12.0 ± 2.7 10.9 ± 2.2* 0.46 Group 0.457 (0.072)
NDK 11.3 ± 2.6 10.9 ± 2.7 0.17 Time x Group 0.447 (0.074)
VAT CG 757.7 ± 265.3 759.4 ± 317.2 0.01 Time 0.031 (0.203)
KD 688.9 ± 125.4 592.4 ± 103.1* 0.84 Group 0.490 (0.066)
NDK 658.0 ± 200.5 624.2 ± 201.5 0.17 Time x Group 0.130 (0.177)
LBM CG 65.6 ± 2.6 66.4 ± 3.5 0.26 Time 0.023 (0.224)
KD 66.8 ± 6.8 66.5 ± 6.9 0.04 Group 0.516 (0.061)
NDK 63.2 ± 4.4 64.6 ± 4.2* 0.31 Time x Group 0.025 (0.297)
Data are means ± SD; Greenhouse-Geisser univariate p-levels are presented for each variable; p< 0.05 is considered significant; (*) denotes a significant difference
from baseline; ES Effect Size (Cohens d), BW Total body weight, FM Fat mass, VAT Visceral adipose tissue, LBM lean body mass
Vargas et al. Journal of the International Society of Sports Nutrition (2018) 15:31 Page 5 of 9
studies have reported a reduction in FM during and after
KD, but with a concomitant loss of of LBM [3844]. For
example, Gomez-Arbelaez [45], found that a low-calorie
KD (starting in the initial phases with 600800 kcal per
day and following the PNK® method) resulted in a de-
crease in VAT, according to a follow-up study performed
over 4 months. Notwithstanding, it should be noted that
these studies included obese subjects, in some cases with
at least one cardiovascular risk factor and, with no phys-
ical exercise intervention, strength training in particular.
In another study [46], there was a reduction in adipose
mass tissue and a parallel increase in LBM after per-
forming a variety of strength or resistance exercises in
moderately active subjects with normal weight; these
changes in body composition (especially FM reduction)
were attributed in part to a decrease in insulin concen-
trations. It is probable that the incorporation of RT,
together with moderate/high protein consumption and a
caloric surplus, may be an important strategy for main-
taining fat free mass during KD. In particular, RT alone,
or combined with endurance training, accompanied by a
hypoenergetic KD, might be useful for the preservation
of fat free mass and the increased metabolic rate in
obese subjects, as an intervention that deserves further
research, considering the complexity of this multifactor-
ial illness [47]. In fact, even though endurance exercise
is more effective than RT in reducing VAT [48], a com-
bination of endurance training and RT is more plausible
for improving body composition in this population [49].
Since few studies have evaluated the combined effect of
the KD and RT in trained subjects on VAT, our study
contributes to current literature by showing a significant
reduction in VAT after 8 weeks of KD in hyperenergetic
condition in resistance-trained men. These results sug-
gest that KD group achieved a positive change in body
composition, due to a decrease in BW (0.9 [2.3, 0.6]
kg; p> 0.05) with a reduction in FM (0.8 [1.6, 0.1]
kg; p< 0.05) and accompanied by a notably lower VAT
(96.5 [159.0, 34.0] g; p< 0.05). This supports the
need for in-depth analysis about the importance of
macronutrient distribution, comparing isoenergetic nu-
tritional programs, on the distribution of body fat.
On the other hand, animal studies on ketosis-induced
interventions after KD have not found neither acute nor
chronic changes in hypertrophic response in skeletal
muscle, when strength exercises were performed, in
comparison with a mixed diet of macronutrients [50];
however, a reduction in FM was observed in these ro-
dents [51]. Although these results were obtained in
animal models, it seems that these effects are similar but
not extrapolable to humans. Our study involved
resistance-trained young men with an RT program inter-
vention focused on mechanical tension to generate
changes in LBM, considering this as one of the main fac-
tors of RT-induced muscle hypertrophy [29,52,53].
Also, a 3 min-rest pause between sets and short time
under tension was considered, to discourage a dramatic
decrease in muscle glycogen. Subsequently, comparison
of changes in variables, by one-factor ANOVA, revealed
a difference between means in all groups regarding BW
and LBM; in fact, there was an increase in LBM (1.3
[0.5,2.2] kg; p< 0.05) in the NKD group, leading to an
increase in BW (0.9 [2.3, 0.6] kg; p< 0.05). Figure 3
shows significant differences in BW and LBM for NKD
group; and FM and VAT for KD group. Likewise,
post-hoc analysis showed significant difference in the
BW and LBM between KD and NDK groups. These re-
sults are in agreement with those obtained by Rauch et
al. [54], who compared the effects of a KD (5% CHO,
75% fat and 20% protein) with a traditional western diet
(55% CHO, 25% fat and 20% protein) in men undergoing
RT training (n= 26), during 11 weeks. These authors
also found a decrease in FM in the KD group but, unlike
our results, there was an increase in LBM.
The results of the present study are in accordance with
thepreliminaryhypothesis,sinceanalysisofthedatashowed
a significant reduction in FM and VAT in resistance-trained
men undergoing a KD while participating in a RT
Fig. 3 Changes in body mass and body composition. Mean changes
with 95% CIs completely above or below the baseline are significant
changes; BW: Total body weight; FM: Fat mass; VAT: Visceral adipose
tissue; LBM: lean body mass. aChanges in BW, FM, LBM. bChanges in
VAT. ǂSignificant difference with KD after post-hoc analysis (p<0.05)
Vargas et al. Journal of the International Society of Sports Nutrition (2018) 15:31 Page 6 of 9
program; however, no changes were seen in LBM in
this group. The clinical significance is the reduction in
VAT, which could have health benefit because of its in-
verse correlation to cardiometabolic disease [55,56].
Regarding to LBM, an adequate carbohydrate intake
(non-ketogenic or conventional dietary approach), in con-
junction with a caloric surplus and a higher protein intake,
might be the most viable option for inducing muscle
hypertrophy after RT.
Limitations
This study has several limitations that should be men-
tioned. Firstly, this research only included body compos-
ition measurements and did not include blood measures.
In addition, limited outcome measurements, small num-
ber of subjects and intervention time (8 weeks) reduce
the impact of the study. On the other hand, dietary as-
sessment of appetite suppression by high-fat diet was
not performed. So, it is possible to have variations in en-
ergy intake even though participants were instructed to
follow specific dietary recommendations. Moreover,
since KD may affect negatively training volume, we
should consider integrating performance measurements
or load volume to see changes. In addition, rated
perceived exertion might give interesting information
about changes during KD adaptation and progression of
RT protocol.
Conclusions
According to our results, we concluded that subjects
who underwent RT during a KD experienced a greater
reduction in FM and VAT, when compared to the NKD
group. The greater reduction in VAT may have some
clinical relevance due to its inverse association to
cardio-metabolic risk. Further studies are necessary to
evaluate the advantages of this combination (RT and
KD) in subjects with excess of body FM, with particular
attention to the reported significant reduction in VAT,
which might be highly beneficial to this population given
that LBM is maintained. Indeed, this research showed
no significant changes nor effect size on LBM, despite
hyperenergetic condition and high protein intake
(2.0 gkg
1
d
1
) in resistance-trained men of the KD
group. Thus, we conclude that low-carbohydrate dietary
approaches, such as KD, would not be an optimum
strategy for building muscle mass in trained men under
the training conditions of this study (mechanical
tension-focused RT protocol during 8 weeks).
Abbreviations
ANOVA: One-way analysis of variance; BMI: Body mass index; BW: Body
weight; CG: Control group; DXA: Dual-energy x-ray absorptiometry; ES: Effect
size; FM: Fat mass; KB: Ketogenic bodies; KD: Ketogenic diet; LBM: Lean body
mass; NKD: Non-ketogenic diet; RT: Resistance training; VAT: Visceral adipose
tissue; ηp
2
: Partial eta squared effect size
Acknowledgments
We are grateful to MSc. Kelly Salgado for her helpful statistics advice.
Funding
Supported by University of Málaga (Campus of International Excellence
Andalucía Tech).
Availability of data and materials
The datasets used and analyzed during the current study are available from
the corresponding author on reasonable request.
Authorscontributions
SV served as study coordinator. SV and IG conceived and designed the
experiments. JBP and RR served as lab coordinator and project manager for
the study coordination. SV, RR, and JBP assisted in data collection. SV, SE, and
IG designed the nutritional protocols. SV oversight nutrition and training. JLP
and RBK analyzed the data. JLP, RBK, JBP, and DAB assisted in analysis, and
manuscript review. SV, JLP, DAB and JBP wrote the paper. RBK assisted in the
statistics advice, discussion analysis, and manuscript preparation. All authors
read and approved the final manuscript.
Ethics approval and consent to participate
Participation in the study was voluntary, with written consent being
obtained from each subject before the initiation of data collection. This
study was conducted after review and approval by the Ethics Committee of
the EADE-University of Wales Trinity Saint David (Málaga, Spain). Committees
reference number: EADECAFYD2017-3.
Consent for publication
Not applicable.
Competing interests
The authors declare that they have no competing interests.
PublishersNote
Springer Nature remains neutral with regard to jurisdictional claims in
published maps and institutional affiliations.
Author details
1
EADE-University of Wales Trinity Saint David, Málaga, Spain.
2
Human Kinetics
and Body Composition Laboratory, Faculty of Education Sciences, University
of Málaga, Málaga, Spain.
3
Research Group in Physical Activity, Sports and
Health Sciences, Universidad de Córdoba, Montería, Colombia.
4
Department
of Biochemistry and Molecular Biology, Universidad Distrital Francisco José
de Caldas, Bogotá, Colombia.
5
BetterbyScience, Málaga, Spain.
6
Exercise &
Sport Nutrition Lab, Human Clinical Research Facility, Texas A&M University,
College Station, TX, USA.
Received: 8 March 2018 Accepted: 26 June 2018
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... This reduction may impair training session performance by limiting energy regeneration, leading to an inability to sustain elevated force production throughout the training session (25). For example, some studies have reported impaired performance and adaptations following a low-CHO diet (17,25,31,43). Moreover, some studies report blunted gains in muscle mass when RT is combined with lower-versus higher-CHO diets (17,18,31,43), suggesting that low-CHO diets are suboptimal for maximizing muscle growth. ...
... For example, some studies have reported impaired performance and adaptations following a low-CHO diet (17,25,31,43). Moreover, some studies report blunted gains in muscle mass when RT is combined with lower-versus higher-CHO diets (17,18,31,43), suggesting that low-CHO diets are suboptimal for maximizing muscle growth. However, it should be noted that the low-CHO-diet groups in these studies were most likely in a caloric deficit, which conceivably impairs anabolic responses to RT (2). ...
... Despite some investigations showing a benefit of low-CHO diets in reducing fat mass (17,31,32,43), our results indicated no effect for either condition in this body composition component. Given the well-established theory that energy balance dictates changes in body mass (39), it is possible to believe that the participants in both groups were not in a caloric deficit. ...
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... The loss of FFM in the meta-analysis of Ashtary-Larky [8] may be due to the fact that, of the thirteen studies evaluated, eight were carried out ad libitum [13,14,29,[32][33][34][35][36], and one of them did not report the nutritional data [37]. Therefore, only four studies included specific prescriptions for the consumption of total calories [12,27,28,38]. However, while Vargas et al. [12] initially prescribed ≈39 kcal·kg −1 ·d −1 , there was no nutritional record; therefore, we cannot say that the participants consumed the total energy required. ...
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... The high-performance liquid chromatography method, with photodiode array detection, was used for the assessment of serum antioxidants. In order to obtain more reliable results, a fasting sample was obtained and the exposure of the serum to sunlight or other sources of full spectrum radiation was avoided [26]. Serum antioxidant data were expressed in µmol/L, with the exception of retinol, which was expressed in µg/dL. ...
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... It appears that a non-calorie-restricted KD can be used for optimizing BM and body composition. (8) Literature suggests that KD might be an alternative dietary approach to decrease fat mass and visceral adipose tissue without decreasing lean body mass. (9,10) Individuals using ketogenic diet experience fast weight loss in the initial 4 weeks or less. ...
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... 2.5.1. Body Composition DXA measurements will be performed following all current recommendations and the laboratory procedures reported in previous articles published by our research group [46][47][48]. To perform the scans, a Lunar Prodigy™ unit will be used (General Electric Healthcare, Madison, WI, USA). ...
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The ketogenic diet (KD) is increasingly being used to treat patients with intractable epilepsy. Despite decades of research, the reason for its success, when anticonvulsants have failed, is still not completely understood. There are, however, many candidate mechanisms which can be grouped into those that alter neuronal excitability at the synapse, and those that confer neuroprotection. The molecular underpinning of these mechanisms centres on the shift from glucose- to lipid-based energy generation that accompanies a high fat/low carbohydrate diet. Here we describe how changes in the relative abundances of energy substrates (ketone bodies), intermediates of glycolysis and fat metabolism, and metabolic end products (ATP, reactive oxygen species) underlie many of the antiepileptic effects of the KD. We propose that the success of the KD for treating epilepsy lies in the large variety of antiepileptic mechanisms that it confers. Different subsets of the mechanisms may be clinicallyrelevant in different patients. We extend this to suggest that the broad benefits of the KD could therefore be achieved by pharmacologically promoting the production of ketone bodies in the liver as they represent a key mediator that is common to all of the proposed mechanisms.
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Dietary interventions are the cornerstone of obesity treatment. The optimal dietary approach to weight loss is a hotly debated topic among health professionals and the lay public alike. An emerging body of evidence suggests that a higher level of adherence to a diet, regardless of the type of diet, is an important factor in weight loss success over the short and long term. Key strategies to improve adherence include designing dietary weight loss interventions (such as ketogenic diets) that help to control the increased drive to eat that accompanies weight loss, tailoring dietary interventions to a person's dietary preferences (and nutritional requirements), and promoting self-monitoring of food intake. The aim of this paper is to examine these strategies, which can be used to improve adherence and thereby increase the success of dietary weight loss interventions.
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Although the effects of short versus long inter-set rest intervals in resistance training on measures of muscle hypertrophy have been investigated in several studies, the findings are equivocal and the practical implications remain unclear. In an attempt to provide clarity on the topic, we performed a systematic literature search of PubMed/MEDLINE, Scopus, Web of Science, Cochrane Library, and Physiotherapy Evidence Database (PEDro) electronic databases. Six studies were found to have met the inclusion criteria: (a) an experimental trial published in an English-language peer-reviewed journal; (b) the study compared the use of short (≤60 s) to long (>60 s) inter-set rest intervals in a traditional dynamic resistance exercise using both concentric and eccentric muscle actions, with the only difference in resistance training among groups being the inter-set rest interval duration; (c) at least one method of measuring changes in muscle mass was used in the study; (d) the study lasted for a minimum of four weeks, employed a training frequency of ≥2 resistance training days per week, and (e) used human participants without known chronic disease or injury. Current evidence indicates that both short and long inter-set rest intervals may be useful when training for achieving gains in muscle hypertrophy. Novel findings involving trained participants using measures sensitive to detect changes in muscle hypertrophy suggest a possible advantage for the use of long rest intervals to elicit hypertrophic effects. However, due to the paucity of studies with similar designs, further research is needed to provide a clear differentiation between these two approaches.
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Background: Ketogenic diets (KDs) have gained popularity among patients and researchers alike due to their putative anti-tumor mechanisms. However, the question remains which conclusions can be drawn from the available human data thus far concerning the safety and efficacy of KDs for cancer patients. Methods: A realist review utilizing a matrix-analytical approach was conducted according the RAMESES publication standards. All available human studies were systematically analyzed and supplemented with results from animal studies. Evidence and confirmation were treated as separate concepts. Results: 29 animal and 24 human studies were included in the analysis. The majority of animal studies (72%) yielded evidence for an anti-tumor effect of KDs. Evidential support for such effects in humans was weak and limited to individual cases, but a probabilistic argument shows that the available data strengthen the belief in the anti-tumor effect hypothesis at least for some individuals. Evidence for pro-tumor effects was lacking completely. Conclusions: Feasibility of KDs for cancer patients has been shown in various contexts. The probability of achieving an anti-tumor effect seems greater than that of causing serious side effects when offering KDs to cancer patients. Future controlled trials would provide stronger evidence for or against the anti-tumor effect hypothesis
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Purpose: The ketogenic diet (KD) has been proven to be effective in children with refractory epilepsy and is recommended by the National Institute of Health and Care Excellence (NICE). There is no randomised control trial (RCT) evidence for the clinical or cost effectiveness of KD in adults, for whom the KD is not currently recommended. We assessed the feasibility of the modified ketogenic diet (MKD) in adults with refractory epilepsy along with the willingness of patients to participate in a future RCT. Methods: The service evaluation was undertaken in two parts; questionnaire and diet evaluation. Results: 102 patients completed a questionnaire, of which 51 patients were willing to try the MKD for 3 months to assess effect on seizures. Forty three patients were willing to participate in a clinical trial to investigate deliverability, efficacy and tolerability. Thirty seven of which would still be willing to participate if the trial were randomised. Of the 17 patients who commenced the diet, 9 completed the 12 week period, 7 of which stayed on the diet for the longer term. Constipation (n=6) and loose stools (n=3) were the only reported adverse effects. Conclusion: Our results indicate that there is demand for a ketogenic diet service in adults. The MKD is well tolerated, feasible and financially viable to deliver to adults with epilepsy in the NHS. There is also interest in and willingness to participate in a UK based RCT that would ultimately inform decisions about commissioning appropriate services.
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Americans have embraced a large number of diets in an attempt to manage obesity, improve quality of life, and address specific health problems. Among diets developed to address health problems, the ketogenic diet has had a long and variable history. Developed in the 1920s by a faith healer to help children with epilepsy, this diet induces a state that mimics carbohydrate starvation. As medications became available and effectively addressed seizures, the diet fell out of favor. During the last few decades, researchers and clinicians have learned that it can be useful in children and adults with refractory epilepsy and a variety of other conditions. Once again, pharmacists may encounter patients who are employing dietary management of serious health problems. This very high-fat diet almost eliminates carbohydrates from the patient's food selection. The result is the substitution of ketone bodies as a source of energy. Today's ketogenic diet has been modified with scientifically proven adjustments to increase palatability and help with adherence. Effective for some forms of epilepsy, the ketogenic diet also seems to have some utility in Alzheimer's disease, Parkinson's disease, and glaucoma, and many Americans are using it to lose weight. Consultant pharmacists may field questions about this diet, its potential to correct or alleviate health conditions, and its limitations. The article discusses the ketogenic diet's strengths, limitations, potential mechanisms, and use in a number of conditions with an emphasis on the elderly.