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The effect of an 8-week low carbohydrate high fat (LCHF) diet in sub-elite Olympic weightlifters and powerlifters on strength, body composition, mental state and adherence: a pilot case-study

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The effect of low carbohydrate, high fat (LCHF) diets on performance in weight-class restricted strength athletes is inconclusive. However, an LCHF diet could be an effective weight-loss strategy for competition preparation, provided strength is maintained. This study examined the LCHF utility, quantitatively and qualitatively, in five sub-elite level Olympic weightlifters and powerlifters during an 8-week intervention. Two sub-elite Olympic weightlifters and three sub-elite power lifters completed an 8-week LCHF intervention. Carbohydrate was reduced to 1g/kg/day, protein maintained at baseline levels and fat eaten ad libitum. Pre-and post-quantitative measures included strength performance, skinfold measurements, muscle ultrasound imaging and a psychometric questionnaire (recorded daily). Qualitative measures included a written questionnaire and post intervention in-person interviews. Four out of five participants reduced body weight (2.1-3.6 kg). Three participants’ skinfolds decreased (11.0-27.3 mm). Two participants’ strength increased after the intervention similarly to retrospective performances; two participants’ strength remained unchanged; one participant’s absolute and relative strength decreased. DALDA analysis showed statistically significant trends (p<0.05) in multiple participants for “tiredness” and “need for rest” with a greater prevalence of ‘worse than normal’ scores during the intervention. Low energy and fatigue were identified as common themes during the initial weeks of the LCHF intervention. Overall, the participants found the diet acceptable for their training and lifestyle. An 8-week LCHF diet had no detrimental effect on performance in four of five athletes, yet allowed for a reduction in body weight and skinfolds. An LCHF diet could be appropriate for strength athletes when timing, training phase, lifestyle and individual food preferences are considered. Future research should target a larger cohort to investigate possible LCHF benefits for strength athletes.
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Journal of Australian Strength and Conditioning
Volume 25 | Issue 2 | 2017
28
The effect of an 8-week low carbohydrate high fat (LCHF) diet in sub-elite Olympic weightlifters and powerlifters on strength, body composition,
mental state and adherence: A pilot case-study. J. Aust. Strength Cond. 25(2) 6-13 2017 © ASCA.
Case Study
THE EFFECT OF AN 8-WEEK LOW CARBOHYDRATE HIGH FAT (LCHF) DIET IN SUB-ELITE
OLYMPIC WEIGHTLIFTERS AND POWERLIFTERS ON STRENGTH, BODY COMPOSITION,
MENTAL STATE AND ADHERENCE: A PILOT CASE-STUDY.
Simon Chatterton, MSpEx1, Dr Caryn Zinn, PhD2, Eric Helms, MPhil, MSc1 & Dr Adam Storey, PhD1
1Auckland University of Technology, Sports Performance Research Institute, Auckland, New Zealand
2 Auckland University of Technology, Department of Sport and Recreation, Auckland, New Zealand
BLUF
An 8-week low carbohydrate high fat (LCHF, habitual protein intake, carbohydrate intake to 1g/kg/day and fat intake ad
libitum) diet had no detrimental effect on strength performance on four of five athletes, yet positively impacted body
composition and mental state.
ABSTRACT
Purpose
The effect of low carbohydrate, high fat (LCHF) diets on performance in weight-class restricted strength athletes is
inconclusive. However, an LCHF diet could be an effective weight-loss strategy for competition preparation, provided
strength is maintained. This study examined the LCHF utility, quantitatively and qualitatively, in five sub-elite level
Olympic weightlifters and powerlifters during an 8-week intervention.
Methods
Two sub-elite Olympic weightlifters and three sub-elite power lifters completed an 8-week LCHF intervention.
Carbohydrate was reduced to 1g/kg/day, protein maintained at baseline levels and fat eaten ad libitum. Pre-and post-
quantitative measures included strength performance, skinfold measurements, muscle ultrasound imaging and a
psychometric questionnaire (recorded daily). Qualitative measures included a written questionnaire and post
intervention in-person interviews.
Results
Four out of five participants reduced body weight (2.1-3.6 kg). Three participants’ skinfolds decreased (11.0-27.3 mm).
Two participants’ strength increased after the intervention similarly to retrospective performances; two participants’
strength remained unchanged; one participant’s absolute and relative strength decreased. DALDA analysis showed
statistically significant trends (p<0.05) in multiple participants for “tiredness” and “need for rest” with a greater prevalence
of ‘worse than normal’ scores during the intervention. Low energy and fatigue were identified as common themes during
the initial weeks of the LCHF intervention. Overall, the participants found the diet acceptable for their training and
lifestyle.
Conclusion
An 8-week LCHF diet had no detrimental effect on performance in four of five athletes, yet allowed for a reduction in
body weight and skinfolds. An LCHF diet could be appropriate for strength athletes when timing, training phase, lifestyle
and individual food preferences are considered. Future research should target a larger cohort to investigate possible
LCHF benefits for strength athletes.
Key Words - low carbohydrate high fat diet, strength, anthropometry, adherence.
INTRODUCTION
Low carbohydrate, high fat (LCHF) diets have more recently become a research focus for addressing metabolic health
as well as enhancing athletic performance (34,35,37). For strength and power athletes, guidelines suggest consumption
of 4-7 g/kg/day of carbohydrate in order to prevent any detrimental effects on strength and power performance (39).
Similar to recommendations for endurance athletes, this range is used depending on the athlete’s training phase (39).
Endurance-based research has shown metabolic adaptations from LCHF diets that enhance fat metabolism, in hopes
that this will lead to a subsequent increase in submaximal exercise performance (25,35,50). Strength and power athletes
consuming LCHF diets have shown spontaneous reductions in caloric intake and consequent body weight reductions,
potentially improving strength-to-weight ratio (34,37). The benefits of LCHF diets in such athletes are speculative (19),
with evidence showing negative (22,49) or neutral effects on performance (34,37). The detrimental effects reported in
some studies may be due to the combination of enforced carbohydrate and calorie restriction (22,49). In such
circumstances, participants may be unable to maintain performance as this restricted diet may not meet training
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demands (49). However, in studies where only carbohydrate is restricted and calories from fat and protein are
unrestricted, strength and power is maintained (34,37).
Weight-class restricted strength and power athletes commonly train at a higher body weight to increase strength before
‘cutting weight’ to their body weight classification. The balance of dropping weight and maintaining strength is often
hindered by rapid and sometimes detrimental weight-loss practices used by these athletes (3,4,7,29), such as severe
calorie restriction and laxative and sauna use (3). Unfortunately, reducing weight in a gradual fashion (~500g/week)
over time using “best practice” sports nutrition guidelines is rarely considered (17,43). The LCHF diet may play a role
here by its ability to induce a spontaneous calorie deficit and facilitate weight loss in a safe and sustainable manner that
may not be experienced as “dieting”. This combination may prove beneficial for weight-class restricted athletes
attempting to make weight while maintaining performance (37).
There is very little qualitative information regarding the experience of athletes who have followed LCHF diets. Only a
small qualitative note from Paoli et al. (34) identified that some participants found it too challenging to complete training
during the first week of a ketogenic diet, the extreme end of LCHF (<50g of carbohydrate, ~120g of fat and ~ 200g of
protein per day), but that these feelings subsided after that point. Klement et al. (24) used a descriptive analysis in which
physically active participants, who underwent 40 days of a ketogenic diet, were given a short questionnaire to document
their subjective experience during the diet. In this study, it took participants two to three weeks to get through the initial
adaptation period before recovery and energy levels returned to normal. Throughout the ketogenic diet, a common trend
most participants described was the inability to recover quickly from high-intensity (resistance and/or aerobic) exercise.
These results provide some insight into the feasibility of a self-directed ketogenic diet on strength and power
performance. However, more qualitative information is needed to gain further insight into the acceptability of non-calorie
controlled LCHF diets for strength and power athletes.
The present study set out to identify whether an 8-week, non-calorie restricted, LCHF diet would allow for a body weight
reduction without having any detrimental effect on strength performance in anaerobic strength and power athletes.
Specifically, these were sub-elite Olympic weightlifters and unequipped (athletes not using supportive elastic lifting
equipment) power lifters. In addition, we set out to understand the changes in mood and overall experiences via online
completion of Daily Analysis of Life Demands for Athletes (DALDA) forms, a one-on-one interview and a post-study
questionnaire. Carbohydrate intake was set at 1g/kg/day and fat was to be consumed ad libitum. Unlike some versions
of the LCHF diet where protein is eaten ad libitum, protein was matched from the participants’ baseline diets. Thus,
changes observed were likely associated with a higher fat consumption or a reduction in carbohydrate rather than an
alteration in protein. Unlike studies which assessed strength mechanistically, this study used an ecologically valid
assessment of performance: strength was assessed on competition lifts and compared to recent competition
performance (42).
This study was approved by Auckland University of Technology Ethics Committee on 26 May 2014. Ethics
number:14/112.
METHODS
Table 1 - Participant physical characteristics of unequipped powerlifters and Olympic weightlifters.
Unequipped Power lifters
Participant
Gender
Age (years)
Weight (kg)
Height (cm)
1
Male
26
76.2
166
3
Male
24
90.1
177.2
5
Male
31
91.1
184.6
Olympic weightlifters
2
Female
24
78.5
157.5
4
Male
29
95.4
186.9
Participants
Eight participants volunteered for this study. Prior to the start, three participants withdrew themselves due to time
constraints and/or current competition schedule. The remaining five participants met criteria for either 1) an Olympic
weightlifter who qualified within a national ranking of ‘C class’ requirement or above according to Olympic Weightlifting
New Zealand’s standards (33) or, 2) an unequipped powerlifter with a national ranking ‘bronze class’ requirement or
above according to New Zealand Powerlifting Federation’s standards (32). Rankings in each sport are based on total
weight lifted in a competition and vary between weight-classes. Additionally, participants were required to meet the
following criteria: 1) have at least two years of competitive experience; 2) be drug free as per the 2015 World Anti-
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Doping Agency prohibited list (48); 3) have access to nutrition tracking software on a smart phone or computer; 4) not
currently consuming a low carbohydrate diet (below 1g/kg/day); and 5) healthy and injury-free as assessed via a health
questionnaire. Table 1 shows the participant demographics.
Pre: pre-study; C1,2,3,4,5: consultation with participant; Post: post-study
Note: Dietary monitoring data was collected and examined each week throughout the whole 16-week study period.
Figure 1 - Schematic of testing procedures over the 16-week case study.
Testing procedure
Prior to participating, each participant completed a consent and health history form. Five consultations were held
throughout the 16-week study, which is presented diagrammatically in Figure 1. An initial consultation (C1, Week -3)
with each participant was conducted to provide education on tracking procedures for their baseline (habitual) diet and
to conduct an anthropometric assessment. During the last week of the baseline period, a second consultation was
conducted (C2, Week 0). C2 involved providing participants with an LCHF resource, an anthropometric assessment,
ultrasound imaging, and a 1RM assessment if a participant’s most recent competition was not within 2 months of
beginning the study. Participants began their LCHF intervention the following week (Week 1). A third consultation (C3)
occurred during Week 4, which included an anthropometric assessment and an informal discussion on progress. The
fourth consultation (C4, Week 8) involved an anthropometric assessment, ultrasound imaging to assess changes in
muscle morphology, 1RM testing and a one-on-one interview. Participants were then encouraged to return to their usual
eating habits for another 4 weeks (Week 13-16). This part of the study was added for the purpose of assessing,
qualitatively, the athletes’ experiences of returning to usual eating habits after completing LCHF eating. Observations
of changes to diet pattern were made during this period followed by the last consultation (C5) which comprised of a
post-study questionnaire, and in-person interview, allowing participants to reflect back on their experience. DALDA
questionnaires were collected daily through-out the entire study period.
Diet tracking
Daily dietary intake was collected using the My Fitness Pal® mobile phone application and website. Participants received
a My Fitness Pal guidebook and training on how to track their intake. The primary researcher had access to their diet
entries, which were transferred into software with a local food database (FoodWorks®, Xyris Software) for cross-
checking. After Weeks -3 to 0, an average weekly macronutrient intake was calculated, which was identified as the
participants’ baseline diet. Prior to starting the LCHF phase, participants were provided with a hard-copy comprehensive
LCHF resource developed by the researchers along with verbal instructions. The resource outlined some general LCHF-
related dietary guidelines, a list of foods to consume and to avoid, and several recipes. Participants were instructed to
match their baseline protein intake, reduce their carbohydrate to 1g/kg/day and eat fat ad libitum. When the LCHF
intervention commenced, participants continued to track their diet through My Fitness Pal®, which was monitored by a
researcher and a Registered Dietitian, who intervened if any deviation (i.e., more than a 15% deviation in carbohydrate
or protein), was detected. This occurred on one occasion and was rectified for the following day.
Anthropometry assessment
The anthropometric assessment consisted of an eight-site ISAK (International Society for the Advancement of
Kinanthropometry) skinfold protocol measurement (triceps, biceps, subscapular, iliac crest, supraspinale, abdominal,
front thigh and medial calf (40)), using Slim Guide Skinfold Calipers (Creative Health®) and measuring a body weight
using electronic scales (Seca Model 876, Germany). Measurements were conducted at the same time of day and by
the same ISAK- level 1-qualified assessor.
Strength assessment
Strength performances were collected retrospectively from competition records within two months of the start of this
study. These were classified as an absolute strength performance (total) value and a relative strength performance
(Wilks/Sinclair score) value. If the participant had not completed within two months, another strength performance test
was carried out at week -3. A final strength performance test was performed during the last week of the diet intervention
period. All athletes performed their maximal competition lifts in a simulated competition with similar protocols used in
previous research on Olympic weightlifters (42) and powerlifters (26). A certified referee for each respective sport judged
maximal lift attempts for verification. Strength outcomes were collated with participants’ body weights to determine
Re tros pecti ve a nd
ba sel i ne data
LCHF Dietary Intervention
Post
intervention
Daily completion of DALDA and self-reported dietary intake
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Sinclair (Olympic weightlifter) (21) or Wilks (powerlifter) scores (45) for performance comparisons across weight classes.
Thus, both absolute and allometrically scaled strength measures were obtained for each participant. Training volume
was also tracked and recorded.
Ultrasound imaging
Prior to strength assessment, ultrasound (GE Healthcare Vivid S5) images of the quadriceps and triceps were obtained.
Muscle thickness and pennation angle (for rectus femoris only) were measured using techniques similar to the protocols
of Blazevich et al. (9). Triceps muscle thickness of the right arm was obtained using a protocol previously described by
Miyatani et al. (30). Measurements were taken the week prior to the intervention (C2, Week 0) and during Week 8 (C4)
of the intervention. Participants were asked not to perform any resistance training 12 hours prior to testing to reduce
any artificial tissue changes as a result of increased perfusion or inflammatory responses.
DALDA questionnaire
The DALDA questionnaire was used to evaluate stress levels of the athletes throughout the study (36). DALDA forms
were made available to all participants through an online survey website (Survey Monkey®). The DALDA questionnaire
is split into components: Part A contains 9 questions related to sources of stress; Part B contains 25 questions relating
to signs and symptoms of stress (17). For each question in both sections, participants had three answer options; A)
‘Worse than normal’, B) ‘Normal’ or C) ‘Better than normal’. Participants were advised to complete Part A before Part B.
The DALDA form was required to be completed at a similar time each day during the study. Data were collated into a
point system with -1 = ‘Worse than normal’, 0=“Normal” and 1=‘Better than normal. A numeric weekly mean score for
each question from both Part A and Part B was then calculated in addition to a total weekly mean score for all questions
in Part A and Part B. The weekly data were then plotted and analysed using regression analysis to identify any significant
linear or non-linear trends. In addition, each weekly mean DALDA question during the LCHF Dietary intervention was
given a classification and colour coded with either high stress (dark grey), medium stress (light grey) or low stress
(white). This was calculated by taking the largest and smallest stress averages recorded during Weeks 1-8 to provide a
range. If participants missed days due to scheduling conflicts or periods where they were without internet access,
participants were required to backdate entries to allow for a minimum of three entries per week to formulate a weekly
average.
One on one interview and post-study questionnaire
Each participant was interviewed separately for up to 30 minutes during the final week of the LCHF dietary intervention.
These interviews were designed using open-ended questions to ascertain participants’ physical, mental and social
experiences while they were on the LCHF diet. In addition, a post-study questionnaire was emailed to participants with
questions directed towards their overall experience including their return to the post-intervention dietary phase. This
was to identify each participants’ experience of transitioning from the LCHF intervention to their normal dietary habits.
Data analysis
Pre- to post-intervention change scores were expressed as percentage changes for each variable and individual.
Regression was used to identify significant linear or non-linear trends in strength performance and skinfold measures.
A non-parametric Friedman test was used to identify statistical differences between carbohydrate, protein, and fat over
all dietary phases between participants. Analyses were conducted using SPSS (IBM® SPSS® Statistics, version 20)
using an alpha of 0.05. Raw values are presented for ultrasound images rather than regression analyses due to having
only two collections for analysis.
For DALDA data pre- to post-intervention change of sources and symptoms of stress scores were expressed as
percentage changes for each individual. In addition, regression was used to identify any significant linear or non-linear
trends that emerged between the DALDA data and weekly training sessions. All analyses were conducted using SPSS
(IBM® SPSS® Statistics, version 20) using an alpha of p<0.05. Interviews were recorded, transcribed and analysed using
thematic analysis. Thematic analysis was also used to classify categories and themes emerging from the post-
intervention questionnaire. Both sets of transcripts were reviewed to obtain major themes. Sub-themes were then drawn
out within the major themes for a more detailed insight into the data. This was then cross-referenced with the original
transcript to ensure the accuracy of the sub-themes (18).
RESULTS
Diet analysis
All five participants completed the intervention. Macronutrient and energy intakes are presented in Table 2. By design,
participants reduced their carbohydrate intake from 30-48% of total calorie intake to 12-16%. Comparatively, protein
intake among participants showed no statistically significant difference throughout the study, whereas carbohydrate and
fat changed significantly (p<0.05) from baseline to intervention. An increase in fat intake varied from 31-41% of total
calorie intake during baseline to 51-66% during the intervention.
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Table 2 - Mean ± SD values of macronutrient (in grams) and energy (in calories) during the 16-week study.
Figure 2 shows the mean daily calorie intake of each participant from baseline through each week of the intervention.
During Week 1, four participants’ intake reduced by 3.4-33.1%, while one participant showed an increase of 4.0%.
Following Week 1, Participants 1, 3, 4 and 5 linearly increased their intake in subsequent weeks. Participants 1, 4 and
5 finished with a daily calorie intake of 8.4%, 34.6% and 3.5%, respectively, above their baseline levels. Participant 2
reached their initial baseline calories and Participant 3 remained 9% below initial baseline calories.
Figure 2 - Percentage change of mean weekly calorie intake during LCHF intervention compared to baseline.
-40
-30
-20
-10
0
10
20
30
40
Mean weekly calorie intake percentage
change from baseline
LCHF Intervention (weeks)
Participant 1
Participant 2
Participant 3
Participant 4
Participant 5
Baseline (4 weeks)
Participant
Carbohydrate
Protein
Fat
Calories
1
160.3 ± 16.9
159.9 ± 16.3
81.6 ± 17.2
2131 ± 173
2
167.2 ± 13.9
86.4 ± 12.2
67.45 ± 10.1
1659 ± 167
3
241.0 ± 126.1
236.2 ± 34.2
155.9 ± 23.9
3377 ± 645
4
197.0 ± 32.1
146.7 ± 14.7
69.0 ± 17.8
2031 ± 287
5
344.8 ± 25.8
167.6 ± 17.4
101.0 ± 3.7
2890 ± 183
LCHF Intervention (8 weeks)
Participant
Carbohydrate
Protein
Fat
Calories
1
67.2 ± 9.5
178.3 ± 19.0
125.1 ± 11.5
2167 ± 129
2
60.0 ± 13.0
102.4 ± 8.9
90.1 ± 15.2
1490 ± 150
3
87.0 ± 15.8
234.9 ± 37.8
167.6 ± 42.3
2680 ± 450
4
79.7 ± 6.7
150.9 ± 4.8
154.4 ± 13.4
2299 ± 114
5
82.4 ± 7.8
163.5 ± 12.3
197.2 ± 27.8
2692 ± 252
Post intervention (4 weeks)
Participant
Carbohydrate
Protein
Fat
Calories
1
150.3 ± 16.5
183.8 ± 15.6
88.0 ± 45.4
2275 ± 144
2
27.1 ± 8.4
106.7 ± 39.5
54.9 ± 17.4
1299 ± 269
3
192.9 ± 45.5
255.8 ± 23.2
151.4 ± 35.0
3143 ± 492
4
125.0 ± 25.7
159.6 ± 10.6
135.2 ± 23.3
2268 ± 288
5
323.4 ± 22.8
153.7 ± 3.7
121.4 ± 10.5
2930 ± 78
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Anthropometry
Curve fitting for anthropometric data showed no trends among participants. Changes in body weight and skinfolds can
be seen in Table 3. During the intervention, Participants 2-5 lost 2.1-3.6 kg of body weight, which matched a decrease
of 11-27.3 mm in skinfolds. Participant 1 had little-to-no change in either body weight (-0.8kg) or skinfolds (+5.75mm).
Participant 4 lost the most body weight (3.8kgs) and exhibited the greatest decrease in skinfolds (27.3mm/26.9%).
Table 3 - Bodyweight and sum of 8 skinfold percentage changes (with raw values) from baseline, Week 4 and 8 of the
LCHF dietary intervention.
Bodyweight (kg)
Participant
Baseline
Intervention (Week 4)
Intervention (Week 8)
Percentage (kg)
1
76.2
76.1
75.4
-1.0% (-0.8kg)
2
78.5
76.6
76.4
-2.6 % (-2.1 kg)
3
90.1
87.4
87.8
-2.5% (-2.3 kg)
4
95.4
91.1
91.8
-3.8% (-3.6 kg)
5
91.1
88.1
88.7
-2.6% (-2.4 kg)
Sum of 8 skinfolds (mm)
Participant
Baseline
Intervention (4 week)
Intervention (8 week)
Percentage (mm)
1
70
71
75.75
+ 8.2% (+5.75 mm)
2
188.5
185
160
- 15.1%(-25.5mm)
3
83
71
72
- 13.2 % (-11 mm)
4
101.5
71.5
74.25
- 26.9%(-27.25mm)
5
71.5
65
68.5
- 4.0% (-3 mm)
Strength performance
Table 4 shows positive linear trends in retrospective strength performance for Participants 1, 4 and 5 in absolute and
retrospective strength performance (RSP) (total) and relative RSP (Wilks/Sinclair score). Participant 3 only had three
previous RSPs, participant 2’s RSP showed a performance decline from RSP3 leading into the intervention phase, and
participants 1-4 were able to increase their relative strength by maintaining or increasing absolute strength while
decreasing body weight. Participant 5’s absolute and relative strength reduced through a decrease in 1RM deadlift and
squat during post-intervention testing.
Table 4 - Absolute strength performance (Total) and relative strength performance (Sinclair/Wilks score) for
retrospective strength performance (RSP) data and post-intervention testing.
Participant
Metric
RSP1
RSP2
RSP3
RSP4
RSP5
Post intervention
% change (RPS 5 to Post)
1 (PL)
Total
460.0
500.0
520.0
547.5
560.0
560.0
0.0%
Wilks Score
356.8
363.0
377.7
393.8
395.4
397.5
0.4%
2 (OWL)
Total
168.0
174.0
180.0
173.0
169.0
169.0
0.0%
Sinclair
Score
202.5
210.2
217.1
208.5
198.3
200.4
0.6%
3 (PL)*
Total
X
X
452.5
467.5
542.5
557.5
2.8%
Wilks Score
X
X
297.0
304.0
348.3
360.5
3.5%
4 (OWL)
Total
180.0
196.0
210.0
212.0
215.0
217.5
1.2%
Sinclair
Score
201.6
223.9
239.0
242.4
244.7
250.7
2.5%
5 (PL)
Total
585.0
590.0
592.5
592.5
610.0
597.5
-2.1%
Wilks Score
370.0
372.8
375.8
374.3
389.2
384.3
-1.3%
PL: powerlifter; OWL: Olympic Weightlifting; RSP; Retrospective Strength Performance; %: percentage
*did not have five prior competition totals but met all criteria to participate in study
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Ultrasound
Minimal change occurred from pre- to post-ultrasound testing. Changes fell within normal variation for muscle thickness
(<10%) and pennation angle (<14%) (34). Participant 2 had a decrease of 5 mm (10.8% decrease) in triceps muscle
thickness.
DALDA and training volume
‘Tiredness’ and ‘need for rest’ were the only domains from the DALDA questionnaire that had statistically significant
similarities in curve trends (p<0.05) among participants. Participant 1 (p<0.05) and Participant 5’s (p<0.05) ‘tiredness’
increased during LCHF W1 to W2 followed by a return to baseline levels (Table 5). Participants 2, 3 and 4 showed no
trend in tiredness over the 16-week study period.
There were non-linear trends in ‘need for rest’ for Participants 1, 2 and 3 (Table 6). Participant 1 responded with a
decrease in ‘need for rest’ from W1 to W2, while training volume was predominantly moderate to high. This was followed
by an increase in ‘need for rest’ as training volume decreased to low. Conversely, Participant 2’s ‘need for rest’ increased
from W1 to W4, followed by a decrease in ‘need for rest’ from W5 to W7 (See Table 6). Participant 2 suffered a right
shoulder injury during W7. Training volume did not appear to have a relationship with changes to ‘need for rest’.
Participant 3 reported an increase in ‘need for rest’ from W1 to W5, which then regressed back to baseline average in
W6 and W8. This coincided with moderate and low training volume during W7 and W8 respectively. Participants 4 and
5 had no trends associated with need for rest.
Table 5 - Change in weekly total volume (in kg) and percentage of change (%) of mean baseline with DALDA weekly
mean ‘tiredness’ scores during 8-week LCHF intervention.
Participant
Variable
Baseline
Mean
W1
W2
W3
W4
W5
W6
W7
W8
1
Training
volume
24141
36519
(+51.30%)
30775
(+27.5%)
44956
(+86.2%)
30906
(+28.0%)
16875
(-30.1%)
17304
(-28.3%)
6780
(-71.9%)
7720
(-68.0%)
Tiredness*
-0.481
-0.143
-0.167
0.167
-0.286
-0.500
-0.143
-0.400
-0.750
2
Training
volume
20522
6160
(-69.9%)
23226
(+13.2%)
17105
(-16.6%)
13747.5
(-33.0%)
5629
(-72.6%)
17615
(-14.2%)
22550
(+9.9%)
20365
(-0.8%)
Tiredness
(p<0.06)
-0.525
-1.000
-1.000
-1.000
-1.000
-0.667
-0.333
-0.800
-0.833
3
Training
volume
20666
20060
(-2.9%)
25620
(+24.0%)
19802
(-4.2%)
24523
(+18.7%)
21752
(+5.3%)
27560
(+33.4%)
20060
(-2.9%)
14562
(-29.5%)
Tiredness
-0.143
0.000
-0.143
0.000
-0.290
-0.500
-0.143
-0.429
0
4
Training
volume
31638
32910
(+4.0%)
26020
(-17.8%)
33240
(+5.1%)
23768
(-24.9%)
25875
(-18.2%)
11058
(-65.1%)
31815
(+0.6%)
29235
(-7.6%)
Tiredness
-0.364
-0.429
-0.167
0.143
-0.167
0.000
0.000
-0.143
-0.333
5
Training
volume
46196
40025
(-13.4%)
42725
(-7.5%)
43085
(-6.7%)
20422
(-55.8%)
40975
(-11.3%)
14450
(-68.7%)
22292
(-51.7%)
34329
(-25.7%)
Tiredness*
-0.113
-0.250
-0.286
0.000
-0.286
-0.600
-0.500
-0.286
0.000
Note: Dark Grey: High volume/high stress, Light Grey: Medium volume/medium stress, White: Low volume/low stress *Significant trend of p<0.05
Journal of Australian Strength and Conditioning
Volume 25 | Issue 2 | 2017
35
Table 6 - Change in weekly total volume (in kg) and percentage of change (%) of mean baseline with DALDA weekly
mean ‘need for rest’ scores during 8-week LCHF intervention.
Participant
Variable
Baseline
mean
W1
W2
W3
W4
W5
W6
W7
W8
1
Training
volume
24141
36519.5
(+51.30%)
30775
(+27.5%)
44956
(+86.2%)
30906
(+28.0%)
16875
(-30.1%)
17304
(-28.3%)
6780
(-71.9%)
7720
(-68.0%)
Need
for rest*
-0.458
0.000
0.000
0.286
0.000
-0.167
0.143
-0.2
-0.25
2
Training
volume
20522
6160
(-69.9%)
23226
(+13.2%)
17105
(-16.6%)
13747.5
(-33.0%)
5629
(-72.6%)
17615
(-14.2%)
22550
(-9.9%)
20365
(-0.8%)
Need
for rest*
-0.297*
-1.000
-1.000
-1.000
-0.333
-0.500
-0.167
-0.200
-0.667
3
Training
volume
20666
20060
(-2.9%)
25620
(+24.0%)
19802
(-4.2%)
24523
(+18.7%)
21752
(+5.3%)
27560
(+33.4%)
20060
(-2.9%)
14562
(-29.5%)
Need
for rest**
-0.012
-0.286
-0.143
0.000
-0.430
-0.500
-0.290
-0.286
0.000
4
Training
volume
31638
32910
(+4.0%)
26020
(-17.8%)
33240
(+5.1%)
23768
(-24.9%)
25875
(-18.2%)
11058.5
(-65.1%)
31815
(+0.6%)
29235
(-7.6%)
Need
for rest
0
0.143
0.167
0.143
0.000
0.000
0.000
0.000
0.000
5
Training
volume
46196
40025
(-13.4%)
42725
(-7.5%)
43085
(-6.7%)
20422.5
(-55.8%)
40975
(-11.3%)
14450
(-68.7%)
22292.5
(-51.7%)
34329
(-25.7%)
Need
for rest
-0.113
-0.250
-0.286
0.000
0.000
-0.400
-0.500
-0.286
0.000
Note: Dark Grey: High volume/high stress, Light Grey: Medium volume/medium stress, White: Low volume/low stress *Significant trend of p<0.05, **
Significant trend of p<0.01
One-on-one interview and post-study questionnaire
Each participant was interviewed individually during the last week of the LCHF dietary intervention. In addition, each
participant completed a post-study questionnaire that comprised questions relating to diet acceptability, experience of
re-entry into their baseline diet and how they would modify the diet for personal use. In each similar themes across the
five participants were identified. Table 7 summarises the key themes and supporting transcripts from each of the
participants’ interviews and questionnaires. A central theme of positive diet acceptability with respect to the LCHF diet
intervention was drawn out of interview transcripts. Five sub-themes within this major theme were: 1) fear associated
with eating an LCHF diet; 2) surprise with their experience; 3) initial training fatigue; 4) initial satiety; and 5) changes in
mood. The three key themes that emerged from the questionnaire were dietary acceptability, diet re-entry and diet
modification.
The first theme was a fear associated with lowering carbohydrate and increasing fat. Collectively, participants felt as if
they were going to be restricted in training as well as having to consume a lot of fat in their diet. Participants were
generally surprised with their experience of the LCHF diet. The fear subsided and participants were able to adapt
comfortably. All five participants who began the diet were able finish with minimal difficulty.
Participants reported that they enjoyed their dieting and overall surprised with entire experience. Participants 3 and 4
added foods, such as cream and coconut oil, which they enjoyed from the diet into their post-intervention diets. No
negative attitudes to the LCHF intervention were expressed by participants.
Journal of Australian Strength and Conditioning
Volume 25 | Issue 2 | 2017
36
The initial ‘adaptation period’ of the diet involved fatigue. All participants at some point experienced weakness or low
energy during the 8-week period. Participants 1, 3 and 4 had low energy and reported feeling weak occasionally during
the initial four weeks of the diet. However, after this point these negative feelings diminished and returned to normal.
Participants 2 and 5 had varying bouts of fatigue during the 8-week LCHF dietary intervention. In addition, some
participants reported they needed longer recovery times during high volume training weeks.
In addition to fatigue, satiety of the diet was a strong theme featured in the interviews. The feeling of fullness was
associated with the high amount of fat consumed. Participants commented on finding it hard to finish meals, which was
not regularly reported to be a problem when consuming their habitual diet. Participants 2, 4 and 5, who were more
accustomed to dieting, described instances where they were surprised at how little they needed to eat to stay full. It was
described by Participant 5 as “dieting without actually dieting”. In addition, participants who were fatigued on the LCHF
diet found their energy levels were able to stabilise quicker and they had more consistency in their training during the
post-intervention phase.
Changes to mood, feelings of being restricted to certain foods, and social barriers were identified as a theme related to
the LCHF diet. As the diet continued, the novelty of LCHF dieting wore off and frustrations around the types of food the
participants could consume, as well as frustration during social outings where food was central, began to increase. For
example, Participant 5 felt that LCHF dieting was a barrier in their social life and expressed feeling restricted in the types
of foods available. In addition, Participants 4 and 5 noticed changes to their daily mood and they became more irritable
and quicker to anger while on the LCHF diet.
Lastly, each participant had an idea of how this diet could be modified to help them perform optimally. Participants 3
and 5 suggested creating a cyclic pattern with their carbohydrate intake to avoid low energy days. Participant 5 based
this on how they would logically prescribe the diet for themselves based on energy needs. Participant 3 said they would
use high carbohydrate intakes during larger training volume periods to counteract fatigue, which occurred during the
LCHF intervention. Participants 1 and 2 suggested they would reduce their carbohydrate further to elicit more weight
loss. Lastly, Participant 4 stated they would adjust both carbohydrate and fat for optimal performance and keep at a
lower body weight year-round.
Journal of Australian Strength and Conditioning
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37
Table 7 - Themes from interviews and post-study interview with supporting transcripts.
Fear associated with an LCHF diet
“I guess I would feel a bit weaker, and went into the diet with the expectation to lose a little bit of weight.” (Participant 1)
“My initial thoughts were, am I going to have enough energy to do everything because I the reloads (over carbohydrate) that I am
so used to” (Participant 3)
“I thought diet was going to be a good one originally because I have heard a lot about it, especially in the last couple of years it
been brought more to light…” (Participant 5)
“I thought it was pretty gross to be honest, I hold quite an old school mentality that fat is bad…” (Participant 4)
Surprised with their experience
“Well since my skinfolds were going down it was good but I would definitely suggest the meal planning” (Participant 2)
“After going through the diet it was more sustainable than I thought. Once my cravings went after about 5 weeks it was ok.”
(Participant 3)
“I feel like my training energy levels are now similar to what they used to be when I was not on the diet and did not have to rest for
longer periods.” (Participant 4)
“I would say for the first four weeks it was, it was doing something cool and different” (Participant 5)
“I was surprised how little I was affected with going so low carb, in terms of training which a good thing, in my mind was that it
allowed to me see that I had more flexibility in a way I set up my macronutrients without having a negative impact in performance.”
(Participant 5)
Initial training fatigue
“I felt during the first week or two I was a bit sluggish but felt pretty good after that” (Participant 1)
“I had some dizzy spells in the first week and thought I was going to pass out which levelled out and did not happen as commonly.
I also had the odd headache but once I sorted out my electrolytes this sorted it out.” (Participant 3)
“When I first started I had a lot less energy and I felt fatigued all the time at training and there were times after every single rep I
would get dizzy to the point of almost passing out.” (Participant 4)
“I couldn’t go as many sets. I just had to go with it and do what I could and just push past it otherwise I would have got more run
down” (Participant 1)
Initial satiety
Yes, my hunger changed. Well at the beginning I was not hunger because of the protein and all that but now it has gone back to”
(Participant 2)
“The first half of it, I remember not being able to finish a meal. We had put together the curry with coconut milk and I could not
finish it, I just felt so full. And now I am a lot hungrier a lot more of the time. I find myself eating faster” (Participant 4)
“I was very satiated during the first three or four weeks and I was surprised how much I was dropping my calories as I was trying
to eat to fullness as I would normally do” (Participant 5)
“…right around week four and now I have been more food focused than I was previously so I would get hungry at a certain point
and aware of food and trying to think about what I am going to eat” (Participant 5)
Changes in mood
“That is something that I have noticed is that I have been more irritable on this diet” (Participant 5)
“…but it was more of a psychological restriction, social restriction would be the best way to put it.”(Participant 5)
“… I was more susceptible to getting angry was heightened, like a lot. Small things that used to never bother me, just like pushed
me over edge. I think I was more fragile” (Participant 4)
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38
DISCUSSION
Overall, participants reduced body weight and maintained strength during the LCHF diet when carbohydrate
consumption decreased to ~ 1g/kg/day and fat consumption increased ad libitum. These findings are consistent with
previous research (34, 37); as a spontaneous calorie decrease and consequent body weight and skinfold reduction was
observed in four out of five participants. Four participants maintained or slightly increased absolute and relative strength,
with one participant (Participant 5) showing a small decrease in both. If unequipped powerlifters do in fact perform with
a similar level of reliability to Olympic weightlifters (as reported in McGuigan et al. (27)), the decrease in strength that
Participant 5 experienced could be within the normal level of variation, however this cannot be definitively concluded. It
should be noted Participant 5 consumed the most carbohydrate (~3.8g/kg/day) relative to others during the baseline
period, thus the contrast in baseline to intervention carbohydrate intake was the highest for this participant, which may
have impacted performance during the intervention.
Each participant was able to reduce carbohydrate to 1g/kg/day or lower while maintaining their baseline protein intake
(1.1-2.6 g/kg/day). Thus, our findings are novel as no study, to our knowledge, has implemented an LCHF diet in this
population where protein has been controlled. Four participants saw a varied initial drop in caloric intake (3%-33%) while
consuming 60-90g of carbohydrates/day during Week 1. Previous research, with carbohydrate <50 g/day and fat and
protein eaten ad libitum, reported a mean calorie reduction of 13-15% compared with participants’ baseline diet over a
4-week period (34, 37). During Week 1, four participants increased their fat intake by 53-91% when compared to
baseline. The initial reduction in calories could be attributed to a reduction in overall appetite as a result of an increase
in the appetite-suppressing hormone, cholecystokinin, secreted in response to dietary fat (CCK), (12, 28). Another
possible reason could have been a fear of adding fat to the diet, which is often the case in practice when LCHF eating
is first initiated. This is due to dietary fat traditionally being the most energy-dense and often avoided macronutrient
when fat loss is the goal (14). This was evident in Participant 3, who decreased fat by 16% during Week 1. Consequent
to the reduction in calories, body weight reduced during Week 4. This could be attributed to both a reduction in body
water, as glycogen depletion is coupled with water loss (5,13) and a loss in body fat, as demonstrated by a reduction in
skinfolds (13.2-26.9%) in Participants 2-4.
Sustained weight loss during the latter portion of the LCHF intervention, while caloric intake increased spontaneously,
was a novel finding. Participants 2, 3 and 4 appeared to preserve fat-free mass (FFM) as skinfolds generally coincided
with weight loss, along with no change in muscle thickness. A possible mechanism to explain this could be a decrease
in the hormonal response, insulin, as a result of the reduced carbohydrate intake, thereby resulting in an increase in fat
utilisation (25). In addition, a reduction in glycogen availability within the muscle and liver can result in a decrease in
insulin receptors and Glut-4 glucose transport mRNA, while fat metabolism increases (25). Increased efficiency of fat
utilisation may drive a greater internal energy production for exercise. Alternatively, an increase in calorie consumption
is often accompanied by an increase in total daily energy expenditure (TDEE), which is not specific to an LCHF
macronutrient intake. Non-exercise activity thermogenesis (NEAT), a component of TDEE, has been identified as a
mechanism for preventing weight gain during periods of calorie surplus (46). NEAT upregulates in some individuals to
dispose of excess energy through heat, limiting fat storage and ultimately weight gain (46).
At the end of the LCHF intervention, all five participants spontaneously increased calorie consumption to above or near
baseline intakes. Interestingly, the increase was not coupled with an increase in body weight or skinfolds. The gradual
increase in calorie intake may have resulted from a down-regulation in satiety, primarily through leptin signalling, as
body weight reduced (31). For example, mild decreases in leptin would result in decreased satiety, shifting body weight
back to normal levels (1,2). This response would be associated with an increase in calorie consumption (1,2). However,
calories would have to substantially increase over TDEE in order to produce measurable weight and fat gain. These
physiological adaptations could be viewed with scepticism as changes could simply be a result of more accurate food
tracking over time. Measuring dietary intake through self-reported tracking is well-researched and comes with inevitable
inaccuracies (8, 23). The advantage of using self-reported mobile- and computer-friendly food tracking allows real-time
data collection and assessment (8, 10, 23). However, digitally recording food intake comes with its own inaccuracies
(16) as under-reporting of food and portion sizes can lead to inconsistent data collection.
Strength performance was either slightly increased or maintained in four participants. During competition preparation
when weight reduction is a goal for many weight-class restricted strength and power athletes, maintaining traditionally
recommended carbohydrate intakes may become difficult (39). An LCHF diet where fat is consumed ad libitum while
carbohydrate is reduced (1 g/kg/day) may allow for maintenance of performance while inducing a small reduction in
body weight. This could be an alternative strategy to other weight loss methods. During competition preparation for
weightlifting, energy expenditure is low due to a reduction in workload whilst tapering (39). Also, during competition itself
there is a reliance on the ATP-CP energy system (44). However, during high volume training, the repeated high-intensity
nature of training (both Olympic lifting and powerlifting) would result in a reliance on other anaerobic pathways which
are fuelled by CHO which should be considered (39). In addition, the high volumes of training required to progress and
compete at the highest levels (42) could be compromised by limiting carbohydrate intake too severely. Therefore, to
maintain strength performance consuming carbohydrate in line with mainstream nutrition guidelines may not be pivotal
in the period immediately preceding (taper phase) and during competition. A recent study reported no statistical
Journal of Australian Strength and Conditioning
Volume 25 | Issue 2 | 2017
39
differences in Olympic weightlifting performance after a carbohydrate reduction from 5.3 g/kg/day to 2.8g/kg/day over a
6-day period (15). However, whether long-term adaptation of an LCHF diet is appropriate for strength or power athletes
and the exact threshold of carbohydrate restriction remains to be seen without additional study.
Trends were seen predominantly in the ‘tiredness’ and ‘need for rest’ DALDA items among participants in the first four
weeks of the LCHF intervention. This coincided with responses during one-on-one interviews that revealed ‘initial fatigue’
as a key theme during the LCHF intervention. Although each participant found the LCHF diet acceptable in terms of
their training and lifestyle, they did recommend that the LCHF diet would be better suited to themselves if it was modified
to their preferences, either implemented in a cyclic fashion throughout a training season or reducing carbohydrate to
ketogenic ranges (<50g of carbohydrate per day). To our understanding, there is no current ‘gold standard’ LCHF
protocol, hence individualisation of LCHF to each athlete in relation to their personal experiences is essential. DALDA
responses and training volume appeared to have a relationship, where high volumes of training increased the stress
response. Therefore, the effects of an LCHF diet on changes to mood and stress may have been masked by different
training phases.
During the interviews, three out of five participants stated that they experienced an increase in fatigue and tiredness
during the initial 1 to 2 weeks of the LCHF dietary intervention. However, this was not reflected in trends reported in
their DALDA questionnaire entries. During severe carbohydrate restriction (i.e. ketogenic diets), this initial fatigue period
is often referred to in the literature as ‘keto-flu’ as the body metabolically regulates itself to use fat as fuel (47). Ketogenic
diet research has suggested individuals may experience fatigue during the initial weeks (24,34). A ketogenic diet was
not employed in this study; however, participants may have experienced a similar, but less severe metabolic adaptation
response to accommodate for a reduction in carbohydrate. Participant 3 had dizzy spells during his training session
during the first week of the LCHF intervention and was advised by our Registered Dietitian to increase their electrolyte
intake, particularly of sodium. This strategy is commonly used for individuals undergoing severe carbohydrate restriction
(47) and was sufficient to alleviate Participant 3’s symptoms of dizziness.
Another major contributor to fatigue could have been the interaction between high training volume and the restriction of
carbohydrate (6). Interviews revealed that there is a possibility that a higher training volume could have been more
difficult during carbohydrate restriction, in particular during the initial weeks of diet adaptation. The variability of different
training volumes could also have affected the signs and symptoms of stress among participants, as DALDA stress
responses are highly sensitive to training volume changes (20, 42). For example, Halson et al. (20) reported an increase
in ‘worse than normal’ responses associated with fatigue during an intensive (high volume) 2-week training block.
Similarly, researchers in a recent study reported that a 2-week intensified training period (i.e. an increase of 12-15% in
training load) in international-level weightlifters coincided with a significant increase in negative mood state along with
an increase in the signs and symptoms associated with stress (42). In this current study, three factors that influenced
higher responses for tiredness and need for rest were: i) periods of high volume training (Participant 5); ii) periods of
high intensity training with low volume (Participant 1); or iii) during the initial 4-week ‘adaptation period’ of the LCHF
intervention (Participant 3). The initial four weeks of the LCHF diet have been previously observed as a period of
adaptation that is frequently discussed in ketogenic diet research (47). These symptoms are expected as the body
undergoes metabolic changes to become more efficient at metabolising fat (29). This re-orchestration of the body’s
metabolism can take some time. The process of fat adaptation causes the body to continue to rely on glycogen stores
under glycogen depletion before progressive enzymatic changes allow for more efficient fat utilisation (29). For example,
Participant 5 had their highest bout of training volume spanning the baseline period and the first four weeks of the LCHF
intervention phase, leading to an increase in tiredness. Once training volume decreased, Participant 5’s stress levels
were able to return back to baseline following a cubic trend (p<0.05).
No current research has yet investigated LCHF diet acceptability qualitatively in dieting athletic populations. However,
it is well known that an LCHF diet can be successfully adhered to for up to 12 months in overweight populations (41),
and may be an alternative for individuals who struggle to adhere to traditional calorie-restricted diets (38). As adherence
to a diet is considered one of the most important variables for weight loss (11), the results of this investigation have
shown that an LCHF diet can be successfully applied to competitive strength and power athletes. Overall there was a
general acceptance of the LCHF diet, as participants commented on overcoming initial fears surrounding dramatic
increases in dietary fat consumption.
CONCLUSIONS AND PRACTICAL APPLICATIONS
The results of this study indicate that the LCHF nutrition approach can result in modest reductions in body weight and
skinfolds in strength and power athletes, without substantial deviations in strength and power performance. While
attention to individual differences is paramount for the sports nutritionist, this nutrition approach could be a viable weight
loss strategy for athletes who have difficulty with enforced calorie restriction and for those seeking safer practices to
elicit weight loss. This study is only a small step towards understanding the effects and potential utility of LCHF nutrition
for strength and power athletes. Further work needs to be undertaken with larger sample sizes, particularly relating to
fuel utilisation during resistance training.
Journal of Australian Strength and Conditioning
Volume 25 | Issue 2 | 2017
40
PRACTICAL APPLICATIONS
Ultimately, an athlete’s compliance with competition preparation is the key to success in any weight-loss period,
regardless of method. Participants’ comments from the post study questionnaire provided an opportunity to understand
athletes’ perspectives on how they would modify an LCHF diet in the future to accommodate a more successful
competition preparation. Participants 1 and 2 suggested a need for a greater reduction in carbohydrate in order to lose
weight. The combination of limited weight loss while experiencing a decrease in stress during the LCHF intervention
may indicate that these participants could have tolerated and perhaps benefitted from a greater carbohydrate reduction
to decrease weight further, or perhaps some other method of modifying energy balance such as a cap on dietary fat
intake or increased energy expenditure. In addition, several participants expressed the possible need to cycle high and
low carbohydrate intakes systematically throughout different phases of training (i.e every 4 weeks), which is a
contemporary topic in sports nutrition and may have potential for optimising strength and power performance. Ideally,
monitoring carbohydrate via an assessable mobile device would provide instant feedback to daily carbohydrate intake
and allow for coaches and/or athletes to understand their individual carbohydrate needs in different training phases.
Further research needs to target how an LCHF diet could be cycled throughout a training year to avoid the monotony of
dieting and to accommodate varying training volumes. Alternatively, research needs to focus on different levels of
carbohydrate restriction to explore changes to energy utilisation in competitive weightlifters who implement LCHF diets
as a way of eating.
Acknowledgements
The authors wish to acknowledge the following people for their assistance Dr Scott Duncan (statistical analysis), Dr
Andrew Kilding (ultrasound measurements), Lee Bridgeman and Scott Brown (data collection).
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... The use of a LCHF diet can be utilized of short-term weight loss in sports that require athletes to meet weight targets. Events such as Olympic weightlifting, boxing, and wrestling compete in weight categories and a LCHF diet has been shown to be effective for reducing fat mass without compromising power and strength in the short term [6,59]. Alternatively, a gymnast looking to reduce weight for performance reasons may also utilize this form of diet to decrease body fat and increase their power to weight ratio [51]. ...
... Considering all the research that has taken place in recent years over the beneficial or detrimental effects of a LCHF diet on athletic performance, there is still further evidence required to provide certainty for both aerobic and anaerobic conditions [57][58][59][60][61][62][63]. The studies reviewed above demonstrate, that the use of LCHF diets in sports warrants more research. ...
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... Since mood was not significantly altered in the present study, this seemingly indicates that high-volume resistance training is well tolerated during a 6-week, moderately energy-restricted high-protein diet in a resistance-trained population. This finding is in line with another study that included resistance-trained individuals under hypocaloric conditions, 43 suggesting that training volume is not necessarily related to stress levels. Other influencing factors however, such as the magnitude of training volume increases over a given time period, baseline training volume familiarization, macronutrient diet content, and the extent of the energy restriction, preclude us from drawing strong conclusions in this regard. ...
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