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Effects of eight weeks of time-restricted feeding (16/8) on basal metabolism, maximal strength, body composition, inflammation, and cardiovascular risk factors in resistance-trained males

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Background Intermittent fasting (IF) is an increasingly popular dietary approach used for weight loss and overall health. While there is an increasing body of evidence demonstrating beneficial effects of IF on blood lipids and other health outcomes in the overweight and obese, limited data are available about the effect of IF in athletes. Thus, the present study sought to investigate the effects of a modified IF protocol (i.e. time-restricted feeding) during resistance training in healthy resistance-trained males. Methods Thirty-four resistance-trained males were randomly assigned to time-restricted feeding (TRF) or normal diet group (ND). TRF subjects consumed 100 % of their energy needs in an 8-h period of time each day, with their caloric intake divided into three meals consumed at 1 p.m., 4 p.m., and 8 p.m. The remaining 16 h per 24-h period made up the fasting period. Subjects in the ND group consumed 100 % of their energy needs divided into three meals consumed at 8 a.m., 1 p.m., and 8 p.m. Groups were matched for kilocalories consumed and macronutrient distribution (TRF 2826 ± 412.3 kcal/day, carbohydrates 53.2 ± 1.4 %, fat 24.7 ± 3.1 %, protein 22.1 ± 2.6 %, ND 3007 ± 444.7 kcal/day, carbohydrates 54.7 ± 2.2 %, fat 23.9 ± 3.5 %, protein 21.4 ± 1.8). Subjects were tested before and after 8 weeks of the assigned diet and standardized resistance training program. Fat mass and fat-free mass were assessed by dual-energy x-ray absorptiometry and muscle area of the thigh and arm were measured using an anthropometric system. Total and free testosterone, insulin-like growth factor 1, blood glucose, insulin, adiponectin, leptin, triiodothyronine, thyroid stimulating hormone, interleukin-6, interleukin-1β, tumor necrosis factor α, total cholesterol, high-density lipoprotein cholesterol, low-density lipoprotein cholesterol, and triglycerides were measured. Bench press and leg press maximal strength, resting energy expenditure, and respiratory ratio were also tested. ResultsAfter 8 weeks, the 2 Way ANOVA (Time * Diet interaction) showed a decrease in fat mass in TRF compared to ND (p = 0.0448), while fat-free mass, muscle area of the arm and thigh, and maximal strength were maintained in both groups. Testosterone and insulin-like growth factor 1 decreased significantly in TRF, with no changes in ND (p = 0.0476; p = 0.0397). Adiponectin increased (p = 0.0000) in TRF while total leptin decreased (p = 0.0001), although not when adjusted for fat mass. Triiodothyronine decreased in TRF, but no significant changes were detected in thyroid-stimulating hormone, total cholesterol, high-density lipoprotein, low-density lipoprotein, or triglycerides. Resting energy expenditure was unchanged, but a significant decrease in respiratory ratio was observed in the TRF group. Conclusions Our results suggest that an intermittent fasting program in which all calories are consumed in an 8-h window each day, in conjunction with resistance training, could improve some health-related biomarkers, decrease fat mass, and maintain muscle mass in resistance-trained males.
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Moro et al. J Transl Med (2016) 14:290
DOI 10.1186/s12967-016-1044-0
RESEARCH
Eects ofeight weeks oftime-restricted
feeding (16/8) onbasal metabolism,
maximal strength, body composition,
inammation, andcardiovascular risk factors
inresistance-trained males
Tatiana Moro1 , Grant Tinsley2 , Antonino Bianco3 , Giuseppe Marcolin1 , Quirico Francesco Pacelli1,
Giuseppe Battaglia3 , Antonio Palma3 , Paulo Gentil5 , Marco Neri4 and Antonio Paoli1*
Abstract
Background: Intermittent fasting (IF) is an increasingly popular dietary approach used for weight loss and overall
health. While there is an increasing body of evidence demonstrating beneficial effects of IF on blood lipids and other
health outcomes in the overweight and obese, limited data are available about the effect of IF in athletes. Thus, the
present study sought to investigate the effects of a modified IF protocol (i.e. time-restricted feeding) during resistance
training in healthy resistance-trained males.
Methods: Thirty-four resistance-trained males were randomly assigned to time-restricted feeding (TRF) or normal
diet group (ND). TRF subjects consumed 100 % of their energy needs in an 8-h period of time each day, with their
caloric intake divided into three meals consumed at 1 p.m., 4 p.m., and 8 p.m. The remaining 16 h per 24-h period
made up the fasting period. Subjects in the ND group consumed 100 % of their energy needs divided into three
meals consumed at 8 a.m., 1 p.m., and 8 p.m. Groups were matched for kilocalories consumed and macronutri-
ent distribution (TRF 2826 ± 412.3 kcal/day, carbohydrates 53.2 ± 1.4 %, fat 24.7 ± 3.1 %, protein 22.1 ± 2.6 %, ND
3007 ± 444.7 kcal/day, carbohydrates 54.7 ± 2.2 %, fat 23.9 ± 3.5 %, protein 21.4 ± 1.8). Subjects were tested before
and after 8 weeks of the assigned diet and standardized resistance training program. Fat mass and fat-free mass were
assessed by dual-energy x-ray absorptiometry and muscle area of the thigh and arm were measured using an anthro-
pometric system. Total and free testosterone, insulin-like growth factor 1, blood glucose, insulin, adiponectin, leptin,
triiodothyronine, thyroid stimulating hormone, interleukin-6, interleukin-1β, tumor necrosis factor α, total cholesterol,
high-density lipoprotein cholesterol, low-density lipoprotein cholesterol, and triglycerides were measured. Bench
press and leg press maximal strength, resting energy expenditure, and respiratory ratio were also tested.
Results: After 8 weeks, the 2 Way ANOVA (Time * Diet interaction) showed a decrease in fat mass in TRF compared
to ND (p = 0.0448), while fat-free mass, muscle area of the arm and thigh, and maximal strength were maintained
in both groups. Testosterone and insulin-like growth factor 1 decreased significantly in TRF, with no changes in
ND (p = 0.0476; p = 0.0397). Adiponectin increased (p = 0.0000) in TRF while total leptin decreased (p = 0.0001),
although not when adjusted for fat mass. Triiodothyronine decreased in TRF, but no significant changes were detected
in thyroid-stimulating hormone, total cholesterol, high-density lipoprotein, low-density lipoprotein, or triglycerides.
© 2016 The Author(s). 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.
Open Access
Journal of
Translational Medicine
*Correspondence: antonio.paoli@unipd.it
1 Department of Biomedical Sciences, University of Padova, Padua, Italy
Full list of author information is available at the end of the article
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Moro et al. J Transl Med (2016) 14:290
Background
Fasting, the voluntary abstinence from food intake for a
specified period of time, is a well-known practice asso-
ciated with many religious and spiritual traditions. In
fact, this ascetic practice is referenced in the Old Tes-
tament, as well as other ancient texts such the Koran
and the Mahabharata. In humans, fasting is achieved
by ingesting little to no food or caloric beverages for
periods that typically range from 12h to 3weeks. Mus-
lims, for example, fast from dawn until dusk during the
month of Ramadan, while Christians, Jews, Buddhists,
and Hindus traditionally fast on designated days or peri-
ods [1]. Fasting is distinct from caloric restriction (CR),
in which daily caloric intake is chronically reduced by
up to 40%, but meal frequency is maintained [2]. In
contrast to fasting, starvation is a chronic nutritional
deficiency that is commonly incorrectly used as a sub-
stitute for the term “fasting”. Starvation could also refer
to some extreme forms of fasting, which can result in
an impaired metabolic state and death. However, starva-
tion typically implies chronic involuntary abstinence of
food, which can lead to nutrient deficiencies and health
impairment. While a prolonged period of fasting is dif-
ficult to perform for the normal population, an inter-
mittent fasting (IF) protocol has been shown to produce
higher compliance [3]. Typically, IF is defined by a com-
plete or partial restriction in energy intake (between 50
and 100% restriction of total daily energy intake) on
1–3days per week or a complete restriction in energy
intake for a defined period during the day that extends
the overnight fast. e most studied of the above form
of IF is Ramadan fasting: during the holy month of
Ramadan, which varies according to the lunar calendar,
Muslims abstain from eating or drinking from sunrise
to sunset. e effects of Ramadan have been extensively
investigated, not only on health outcomes [1, 48],
but also on exercise performance [916]. Moreover, in
recent years a focus on other forms of IF, unrelated to
religious practice, has emerged. One such form, alter-
nate day fasting (ADF; fasting every other day) is organ-
ized with alternating “feast days,” on which there is an
“ad libitum” energy intake, and “fast days” with reduced
or null energy intake.
A growing body of evidence suggests that, in general,
IF could represent an useful tool for improving health
in general population due to reports of improving blood
lipids [1720] and glycaemic control [3], reducing circu-
lating insulin [21], decreasing blood pressure [1, 2123],
decreasing inflammatory markers [7] and reducing fat
mass even during relatively short durations (8–12weeks)
[23]. ese reported effects are probably mediated
through changes in metabolic pathways and cellular
processes such as stress resistance [24], lipolysis [3, 17,
2527], and autophagy [28, 29]. One particular form of IF
which has gained great popularity through mainstream
media is the so-called time-restricted feeding (TRF).
TRF allows subjects to consume adlibitum energy intake
within a defined window of time (from 3–4h to 10–12h),
which means a fasting window of 12–21 h per day is
employed. A key point concerning the IF approach is that
generally calorie intake is not controlled, but the feeding
times are.
In sports, IF is studied mainly in relationship with
Ramadan period [916], whilst TRF has become very
popular among fitness practitioners claiming supposed
effects on maintenance of muscle mass and fat loss. Very
limited scientific information is available about TRF
and athletes, and mixed results have been reported [22,
30, 31]. We demonstrated very recently [30] that TRF
did not affect total body composition nor had negative
effects on muscle cross-sectional area after 8weeks in
young previously-untrained men performing resistance
training, despite a reported reduction in energy intake
of~650kcal per fasting day in the TRF group. us the
aim of the present study was to investigate the effects of
an isoenergetic TRF protocol on body composition, ath-
letic performance, and metabolic factors during resist-
ance training in healthy resistance trained males. We
hypothesized that the TRF protocol would lead to greater
fat loss and improvements in health-related biomarkers
as compared to a typical eating schedule.
Methods
Subjects
irty-four resistance-trained males were enrolled
through advertisements placed in Veneto region’s gyms.
Resting energy expenditure was unchanged, but a significant decrease in respiratory ratio was observed in the TRF
group.
Conclusions: Our results suggest that an intermittent fasting program in which all calories are consumed in an 8-h
window each day, in conjunction with resistance training, could improve some health-related biomarkers, decrease
fat mass, and maintain muscle mass in resistance-trained males.
Keywords: Intermittent fasting, Time-restricted feeding, Resistance training, Body composition, Body builders,
Fasting
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Moro et al. J Transl Med (2016) 14:290
e criteria for entering the study were that subjects
must have performed resistance training continuously
for at least 5years (training 3–5days/week with at least
3 years experience in split training routines), be pres-
ently engaged in regular resistance training at the time
of recruitment, be life-long steroid free, and have no
clinical problems that could be aggravated by the study
procedures.
Fifty-three subjects responded to the advertisement,
but 7 were excluded for previous use of anabolic ster-
oids, and 12 declined participation after explanation of
study’s protocol. erefore, 34 subjects (age 29.21±3.8;
weight 84.6±6.2kg) were randomly assigned to a time-
restricted feeding group (TRF; n=17) or standard diet
group (ND; n = 17) through computer-generated soft-
ware. e research staff conducting outcome assessments
was unaware of the assignment of the subjects (i.e. a sin-
gle blind design). Anthropometric baseline character-
istics of subjects are shown in Table1. All participants
read and signed an informed consent document with the
description of the testing procedures approved by the
ethical committee of the Department of Biomedical Sci-
ences, University of Padova, and conformed to standards
for the use of human subjects in research as outlined in
the current Declaration of Helsinki.
Diet
Dietary intake was measured by a validated 7-day food
diary [3234], which has been used in previous stud-
ies with athletes [35], and analysed by nutritional soft-
ware (Dietnext®, Caldogno, Vicenza, Italy). Subjects
were instructed to maintain their habitual caloric intake,
as measured during the preliminary week of the study
(Table2). During the 8-week experimental period, TRF
subjects consumed 100% of their energy needs divided
into three meals consumed at 1p.m., 4p.m. and 8p.m.,
and fasted for the remaining 16h per 24-h period. ND
group ingested their caloric intake as three meals con-
sumed at 8a.m., 1p.m. and 8p.m. is meal timing was
chosen to create a balanced distribution of the three
meals during the feeding period in the TRF protocol,
while the schedule for the ND group maintained a nor-
mal meal distribution (breakfast in the morning, lunch at
1p.m. and dinner at 8p.m.). e distribution of calories
was 40, 25, and 35% at 1p.m., 4p.m. and 8p.m. respec-
tively for TRF, while ND subjects consumed 25, 40 and
35% of daily calories at 8a.m., 1p.m. and 8p.m. respec-
tively. e specific calorie distribution was assigned by a
nutritionist and was based on the reported daily intake of
each subject.
ND subjects were instructed to consume the entire
breakfast meal between 8 a.m. and 9 a.m., the entire
lunch meal between 1p.m. and 2p.m., and the entire din-
ner meal between 8p.m. and 9p.m. TRF subjects were
instructed to consume the first meal between 1 p.m.
and 2p.m., the second meal between 4p.m. and 5p.m.,
and the third meal between 8p.m. and 9p.m. No snacks
between the meals were allowed except 20g of whey pro-
teins 30min after each training session. Every week, sub-
jects were contacted by a dietician in order to check the
adherence to the diet protocol. e dietician performed a
structured interview about meal timing and composition
to obtain this information.
Table 1 Subject characteristics atbaseline
Results presented as mean±SD. Results are not statistically signicantly
dierent
TRF ND
Age 29.94 ± 4.07 28.47 ± 3.48
Weight (kg) 83.9 ± 12.8 85.3 ± 13
Height (cm) 178 ± 5 177 ± 4
FM (kg) 10.9 ± 3.5 11.3 ± 4.5
FFM (kg) 73.1 ± 5.7 73.9 ± 3.9
Table 2 Diet composition andmacronutrients distribution at basal level and during the experimental period inboth
groups
Results presented as mean±SD. No signicant dierences were detected between groups and within groups
TRF basal TRF exp ND basal ND exp
Total (kcal/day) 2826 ± 412.3 2735 ± 386 3007 ± 444.7 2910 ± 376.4
Carbohydrates (kcal/day) 1503.4 ± 225.95 1400.3 ± 118.8 1654 ± 222.4 1609.2 ± 201.5
Fat (kcal/day) 698 ± 178.5 683.8 ± 61.6 728.7 ± 195 647.7 ± 183.4
Protein (kcal/day) 624.5. ± 59.5 650.3. ± 62.5 637 ± 72.9 643.1 ± 69.3
% Carbohydrates 53.2 ± 1.4 51.2 ± 3.6 54.7 ± 2.2 55.3 ± 4.2
% Fat 24.7 ± 3.1 25 ± 2.8 23.9 ± 3.5 22.6 ± 3.2
% Protein 22.1 ± 2.6 23.8 ± 3.1 21.4 ± 1.8 22.1 ± 3.2
Protein (g/kgbw) 1.86 ± 0.2 1.93 ± 0.3 1.9 ± 0.3 1.89 ± 0.4
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Moro et al. J Transl Med (2016) 14:290
Training
Training was standardized for both groups, and all sub-
jects had at least 5years of continuous resistance train-
ing experience prior to the study. Training consisted of 3
weekly sessions performed on non-consecutive days for
8weeks. All participants started the experimental proce-
dures in the months of January or February 2014.
e resistance training program consisted of 3 differ-
ent weekly sessions (i.e. a split routine): session A (bench
press, incline dumbell fly, biceps curl), session B (mili-
tary press, leg press, leg extension, leg curl), and session
C (wide grip lat pulldown, reverse grip lat pulldown and
tricep pressdown). e training protocol involved 3 sets
of 6–8 repetitions at 85–90 % 1-RM, and repetitions
were performed to failure (i.e. the inability to perform
another repetition with correct execution) with 180s of
rest between sets and exercises [36]. e technique of
training to muscular failure was chosen because it is one
of the most common practices for body builders, and it
was a familiar technique for the subjects. As expected,
the muscle action velocity varied between subjects due to
their different anatomical leverage. Although there was
slight variation of repetition cadence for each subject, the
average duration of each repetition was approximately
1.0s for the concentric phase and 2.0s for the eccentric
phase [37].
e research team directly supervised all routines to
ensure proper performance of the routine. Each week,
loads were adjusted to maintain the target repetition
range with an effective load. Training sessions were per-
formed between 4:00 and 6:00 p.m. Subjects were not
allowed to perform other exercises other than those
included in the experimental protocol.
Measurements
Body weight was measured to the nearest 0.1kg using an
electronic scale (Tanita BWB-800 Medical Scales, USA),
and height to the nearest 1 cm using a wall-mounted
Harpenden portable stadiometer (Holtain Ltd, UK). Body
mass index (BMI) was calculated in kg/m2. Fat mass and
fat-free mass were assessed by dual energy X-ray absorp-
tiometry (DXA) (QDR 4500 W, Hologic Inc., Arling-
ton, MA, USA). Muscle areas were calculated using the
following anthropometric system. We measured limb
circumferences to the nearest 0.001m using an anthro-
pometric tape at the mid-arm and mid-thigh. We also
measured biceps, triceps, and thigh skinfolds to the near-
est 1mm using a Holtain caliper (Holtain Ltd, UK). All
measurements were taken by the same operator (AP)
before and during the study according to standard pro-
cedures [38, 39]. Muscle areas were then calculated using
a previously [40] validated software (Fitnext®, Caldogno,
Vicenza, Italy). Cross-sectional area (CSA) measured
with Fitnext® has an r2=0.88 compared to magnetic res-
onance and an ICC of 0.988 and 0.968 for thigh and arm,
respectively [4042].
Ventilatory measurements were made by standard
open-circuit calorimetry (max Encore 29 System, Vmax,
Viasys Healthcare, Inc., Yorba Linda, CA, USA) with
breath-by-breath modality. e gas analysis system was
used: Oxygen uptake and carbon dioxide output val-
ues were measured and used to calculate resting energy
expenditure (REE) and respiratory ratio (RR) using the
modified Weir equation [43]. Before each measurement,
the calorimeter was warmed according to the manufac-
turer’s instructions and calibrated with reference gases of
known composition prior to each participant.
Oxygen uptake was measured (mL/min) and also nor-
malized to body weight (mL/kg/min), and the respira-
tory ratio was determined. After resting for 15min, the
data were collected for 30min, and only the last 20min
were used to calculate the respiratory gas parameters [37,
44]. All tests were performed in the morning between 6
and 8a.m. while the subjects were supine. e room was
dimly lit, quiet, and approximately 23°C. Subjects were
asked to abstain from caffeine, alcohol consumption
and from vigorous physical activity for 24h prior to the
measurement.
Blood collection andanalysis protocol
Blood samples taken from the antecubital vein at base-
line and after 8weeks were collected in BD Vacutainers
Tubes (SST II Advance, REF 367953). Samples were
centrifuged (4000 RPM at 4°C using centrifuge J6-MC
by Beckman), and the resultant serum was aliquoted
and stored at 80°C. All samples were analysed in the
same analytical session for each test using the same rea-
gent lot. Before the analytical session, the serum sam-
ples were thawed overnight at 4 °C and then mixed.
Interleukin-6 (IL-6), tumor necrosis factor-α (TNF-α),
and interleukin-1β (IL-1β) were measured using Quan-
tikine HS Immunoassay Kit (R&D Systems, Minneapo-
lis, MN, USA). e inter-assay coefficient of variations
(CVs) were 3.5–6.2 and 3.2–6.3% for IL-6, TNF-α and
IL-1β respectively. Insulin-like growth factor 1 (IGF-1)
was measured using the analyzer Liaison XL (DiaSorin
S.p.A, Vercelli-Italy). is test is a sandwich immunoas-
say based on a chemiluminescent revelation, and the CV
for IGF-1 was between 5.6 and 9.6%; the reference range
for this test depends on age and gender. Fasting total cho-
lesterol, high-density lipoprotein cholesterol (HDL-C),
low-density lipoprotein cholesterol (LDL-C), and triglyc-
erides (TG) were measured by an enzymatic colorimet-
ric method using a Modular D2400 (Roche Diagnostics,
Basel, Switzerland). LDL-C fraction was calculated from
Friedewald’s formula: LDL-C=TCHDL-C(TG/5).
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Moro et al. J Transl Med (2016) 14:290
e inter-assay CVs for total cholesterol, HDL-C, and
triacylglycerol concentrations were 2.9, 1.8, and 2.4 %,
respectively. Glucose was measured in triplicate by the
glucose oxidase method (glucose analyzer, Beckman
Instruments, Palo Alto, CA, USA), with a CV of 1.2%.
Leptin and adiponectin were measured by radioim-
munoassay using commercially available kits (Leptin:
Mediadiagnost; Adiponectin: DRG Diagnostic); insulin
was measured with a chemiluminescent immunoassay
(Siemens Immulite 2000). e assay sensitivity was 1ng/
mL, and inter- and intra-assay CVs were less than 10, 5,
and 6% for leptin, adiponectin, and insulin, respectively.
yroid-stimulating hormone (TSH), free thyroxine (T4),
and free triiodothyronine (T3) were measured by auto-
mated chemiluminescence methods (ACS 180 SE; Bayer,
Milan, Italy). Plasma testosterone was determined using
Testosterone II (Roche Diagnostics, Indianapolis, IN,
USA) performed on Modular Analytics E 170 analyzer
with electrochemiluminescent detection.
Strength tests
One repetition maximum (1-RM) for the leg press and
the bench press exercises was measured on separate days.
Subjects executed a specific warm-up for each 1-RM test
by performing 5 repetitions with a weight they could nor-
mally lift 10 times. Using procedures described elsewhere
[45], the weight was gradually increased until failure
occurred in both of the exercises tested. e greatest load
lifted was considered the 1-RM. Previously published
ICCs for test–retest reliability for leg press and bench
press 1-RM testing was 0.997 and 0.997, respectively, in
men, with a coefficient of variation of 0.235 for LP and
0.290 for BP [46]. 1-RM was also assessed at baseline and
after 4 and 8weeks for all training exercises so that the
necessary adjustments for possible strength increases
could be made, thus ensuring that subjects continued to
train at a relative intensity of 85–90% of their 1-RM.
Statistical analysis
Results are presented as mean±standard deviation. e
sample size was obtained assuming an interaction of a
Root Mean Square Standardized Effect (RMSSE) of 0.25
with a fixed power of 80% and an alpha risk of 5% for
the main variable. rough the Shapiro–Wilk’sW test,
we assessed the normality. An independent samples t
test was used to test baseline differences between groups.
e two-way repeated-measures ordinary ANOVA was
performed (using time as the within-subject factor and
diet as the between-subject factor) in order to assess dif-
ferences between groups over the course of the study.
Moreover we adopted a mixed model ANOVA with the
fixed variable fat mass expressed in kg as covariate vs
Time* Diet as random variables. All differences were
considered significant at P<0.05. Post-hoc analyses were
performed using the Bonferroni test. In order to reduce
the influence of within group variability a univariate test
of significance (ANCOVA) was performed. We fixed as
depended variable the Δ pre-post for each group and the
baseline values of the outcomes were adopted as covari-
ate; IF vs ND were assumed as categorical predictors.
e analysis was performed through STATISTICA
software (Vers. 8.0 for Windows, Tulsa, USA) and Prism
5 GraphPad software (Abacus Concepts GraphPad Soft-
ware, San Diego, USA).
Results
After 8 weeks, a significant decrease in fat mass was
observed in the TRF group (16.4 vs 2.8 % in ND
group), while fat-free mass was maintained in both
groups (+0.86 vs +0.64%). e same trend was observed
for arm and thigh muscle cross-sectional area. Leg press
maximal strength increased significantly, but no differ-
ence was present between treatments. Total testosterone
and IGF-1 decreased significantly in TRF after 8weeks
while no significant differences were detected in ND.
Blood glucose and insulin levels decreased significantly
only in TRF subjects and conformingly a significant
improvement of HOMA-IR was detected. In the TRF
group, adiponectin increased, leptin decreased (but this
was not significant when normalized for fat mass), and
T3 decreased significantly compared to ND, without any
significant changes in TSH. No significant changes were
detectable for lipids (total cholesterol, HDL-c and LDL-
c), except for a decrease of TG in TRF group. TNF-α and
IL-1β were lower in TRF at the conclusion of the study
as compared to ND. A significant decrease of respiratory
ratio in TRF group was recorded (Tables3, 4).
Discussion
Fasting is a relatively well-studied metabolic state in
sports and physical exercise due to studies of the “Rama-
dan” period observed by Muslim athletes [12, 14]. How-
ever, only a single study has reported its effect during a
resistance training program aimed at achieving skeletal
muscle growth [30]. Our data demonstrate that during
a RT program, TRF was capable of maintaining mus-
cle mass, reducing body fat, and reducing inflammation
markers. However, it also reduced anabolic hormones
such testosterone and IGF-1.
A key point of the TRF approach utilized in the pre-
sent study is that total daily calorie intake remained the
same while the frequency of meals (i.e. time between
meals) was altered. is is dissimilar to many other IF
regimens. ere are a number of different IF protocols,
most of which have the goal of reducing total energy
intake. Additionally, unlike ADF and some other forms of
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Page 6 of 10
Moro et al. J Transl Med (2016) 14:290
IF, the regimen utilized in the present study employed the
same schedule each day, consisting of 16h fasting and 8h
feeding.
Although IF has received a great amount of attention
in recent years, the majority of studies have investigated
the effects of IF in overweight, obese or dyslipidemic
subjects [1921, 4750]. However, little is known about
the effects of such nutritional regimens in athletes, and
more specifically, in body builders or resistance-trained
individuals. e present study provides the first in-depth
investigation of IF in this population of athletes. With
the exception of reduced triglycerides, our results do not
confirm previous research suggesting a positive effect of
IF on blood lipid profiles [1719, 47, 49, 51, 52], how-
ever, it has to be taken into account that our subjects
were normolipemic athletes. e magnitude of reduction
in triglycerides was also smaller than is typically seen in
individuals who have elevated concentrations prior to IF.
As reported, a decrease of fat mass in individuals per-
forming IF was observed. Considering that the total
amount of kilocalories and the nutrient distribution
were not significantly different between the two groups
(Table2), the mechanism of greater fat loss in IF group
cannot simply be explained by changes in the quantity or
quality of diet, but rather by the different temporal meal
distribution. Many biological mechanisms have been
Table 3 Major results ofexperiment withstatistics adopted highlighted initalics text
Results are presented as mean±SD
n.s. not statistically signicantly dierent (p>0.05)
IF pre IF post ΔIF t test ND pre ND post ΔND t test 2 Way ANOVA
Time*Diet
FFM (kg) 73.08 ± 3.88 73.72 ± 4.27 n.s. 73.93 ± 3.9 74.41 ± 3.59 n.s. n.s.
FM (kg) 10.90 ± 3.51 9.28 ± 2.47 0.0005 11.36 ± 4.5 11.05 ± 4.274 n.s. 0.0448
Arm muscle CSA (cm2) 48.52 ± 3.80 49.37 ± 3.66 n.s. 48.93 ± 4.05 50.17 ± 6.27 n.s. n.s.
Thigh CSA (cm2) 148 ± 34.87 153.77 ± 36.83 n.s. 150.26 ± 22.21 157.35 ± 32.56 n.s. n.s.
Bench press 1-RM (kg) 107.08 ± 18.01 110.36 ± 16.53 n.s. 109.82 ± 14.72 110.57 ± 15.11 n.s. n.s.
Leg press 1-RM (kg) 282.8 ± 30.11 290.00 ± 27.77 n.s. 298.56 ± 25.76 309 ± 68.94 n.s. n.s.
Adiponectin (μg/mL) 11.8 ± 4.3 13.9 ± 3.7 0.0001 10.8 ± 5.5 10.9 ± 4.3 n.s. 0.0000
Leptin (ng/mL) 2.1 ± 0.6 1.8 ± 0.4 0.0002 2.4 ± 0.5 2.3 ± 0.4 n.s. 0.0001
Leptin (ng/mL/kg bw) 0.21 ± 0.07 0.2 ± 0.06 n.s. 0.24 ± 0.11 0.24 ± 0.11 n.s. n.s.
IL-6 (ng/L) 1.33 ± 0.23 1.08 ± 0.22 0.0035 1.24 ± 0.38 1.19 ± 0.33 n.s. n.s.
TNF-α (ng/L) 5.58 ± 0.92 5.13 ± 0.8 0.0001 5.69 ± 0.77 5.86 ± 0.72 n.s. n.s.
IL-1β (ng/L) 0.93 ± 0.19 0.81 ± 0.07 0.0042 0.92 ± 0.12 0.94 ± 0.12 n.s. 0.0235
Testosterone total
(nmol/L) 21.26 ± 6.51 16.86 ± 4.25 0.0001 18.60 ± 5.68 18.85 ± 4.57 n.s. 0.0476
IGF-1 (ng/mL) 216.94 ± 49.55 188.90 ± 31.48 0.0109 215.59 ± 56.25 218.41 ± 42,24 n.s. 0.0397
Insulin (mU/mL) 2.78 ± 0.6 1.77 ± 0.9 0.0303 2.56 ± 0.5 2.22 ± 0.4 n.s. n.s.
TSH (mUI/L) 1.28 ± 0.6 1.27 ± 0.7 n.s. 1.30 ± 0.8 1.31 ± 0.6 n.s. n.s.
T3 (ng/dL) 83.21 ± 17.23 74.32 ± 26.66 0.0001 81.12 ± 20.00 82.35 ± 25.55 n.s. n.s.
Glucose (mg/dL) 96.64 ± 5.1 85.92 ± 7.13 0.0011 95.21 ± 47.77 96.02 ± 65.32 n.s. n.s.
Total cholesterol (mg/
dL) 193.45 ± 6.6 191.37 ± 11.2 n.s. 196.33 ± 9.93 197.12 ± 15.66 n.s. n.s.
Cortisol (ng/mL) 174.25 ± 56.78 186.05 ± 68.5 n.s. 191.24 ± 70.34 185.78 ± 65.89 n.s. n.s.
HDL-c (mg/dL) 54.11 ± 5.89 58.06 ± 6.11 0.0142 53.33 ± 9.67 54.12 ± 9.9 n.s. n.s.
LDL-c (mg/dL) 114.58 ± 11.33 110.26 ± 12.27 n.s. 115.58 ± 9.9 116.08 ± 11.56 n.s. n.s.
TG (mg/dL) 123.78 ± 15.12 115.23 ± 11.77 0.0052 137.10 ± 16.98 134.58 ± 15.66 n.s 0.0201
REE (kcal/day) 1880 ± 94.15 1891 ± 100.56 n.s. 1901 ± 88.76 1895 ± 93.56 n.s. n.s.
RR 0.83 ± 0.02 0.81 ± 0.01 0.0421 0.83 ± 0.03 0.83 ± 0.02 n.s. n.s.
Mixed model ANOVA
with FM as covariate
Adiponectin (μg/mL) 11.8 ± 4.3 13.9 ± 3.7 10.8 ± 5.5 10.9 ± 4.3 0.0000
Leptin (ng/mL) 2.1 ± 0.6 1.8 ± 0.4 2.4 ± 0.5 2.3 ± 0.4 0.0002
Leptin (ng/mL/kg bw) 0.21 ± 0.07 0.2 ± 0.06 0.24 ± 0.11 0.24 ± 0.11 0.0135
IL-1β (ng/L) 0.93 ± 0.19 0.81 ± 0.07 0.92 ± 0.12 0.94 ± 0.12 0.0224
Content courtesy of Springer Nature, terms of use apply. Rights reserved.
Page 7 of 10
Moro et al. J Transl Med (2016) 14:290
advocated to explain these effects. One is the increase of
adiponectin that interacts with adenosine 5-monophos-
phate-activated protein kinase (AMPK) and stimulates
Peroxisome proliferator-activated receptor gamma coac-
tivator 1-alpha (PGC-1α) protein expression and mito-
chondrial biogenesis. Moreover, adiponectin acts in the
brain to increase energy expenditure and cause weight
loss [53]. It is notable that in the present study, the dif-
ferences in adiponectin between groups remained even
when normalized relative to body fat mass, whereas the
significant decrease of leptin (that might be considered a
unfavorable factor for fat loss) was no longer significant
when normalized for fat mass. Other hypothesis is an
enhanced thermogenic response to epinephrine [54] or
an increase in REE [55] after brief periods of fasting, but
our preliminary data didn’t support this point.
Interestingly, although reductions in the anabolic hor-
mones testosterone and IGF-1 were observed, this did
not correspond to any deleterious body composition
changes or compromises of muscular strength over the
duration of the study. It has been previously reported that
men performing caloric restriction have lower testoster-
one than those consuming non-restricted Western diets
[56], however, the present experiment did not restrict
calories in the IF group. In animal models, IF influences
the hypothalamo-hypophysial-gonadal axis and testos-
terone concentration probably through a decrease in
leptin-mediated effects [57], but it must be considered
that mice on a an every-other-day feeding regimen con-
sume about 30–40% less calories over time compared to
free feeding animals and that in our study, no differences
in leptin concentration were seen when normalized for
fat mass. Also, the reduction of IGF-1 in the TRF group
deserves some discussion. A previous study by Bohulel
etal. [11] reported no changes in the GH/IGF-1 during
Ramadan intermittent fasting. Even though it is plausible
that IF mimics caloric restriction through common path-
ways (e.g. AMPK/ACC) (adenosine 5-monophosphate-
activated protein kinase/acetyl-CoA-carboxylase) [58],
recent data on humans showed no influences of caloric
restriction on IGF-1 [59, 60]. It is possible that the
increase of adiponectin and the decrease of leptin could
influence the IGF-1 concentration, even though it is
unclear to what extent changes in adipokines impact cir-
culating IGF-1 levels following weight loss [59].
Previous studies have reported mixed results concern-
ing the ability to maintain lean body mass during IF, but
the vast majority of these studies imposed calorie restric-
tion and did not utilize exercise interventions [22]. In our
study, the nutrient timing related to training session was
different between the two groups, and this could affect
the anabolic response of the subjects [61] even though
these effects are still unclear [62]. However, we did not
find any significant differences between groups in fat-
free mass, indicating that the influence of nutrient timing
may be negligible when the overall content of the diet is
similar.
ere is an increasing amount of data suggesting that
IF could potentially be a feasible nutritional scheme to
combat certain diseases. In the present study, both blood
glucose and insulin concentrations decreased in the IF
group. e potential of IF to modulate blood glucose and
insulin concentrations has previously been discussed, but
primarily in the context of overweight and obese indi-
viduals [3]. e concurrent increase in adiponectin and
decrease in insulin may be related to modulation of insu-
lin sensitivity, as adiponectin concentrations have been
positively correlated with insulin sensitivity [21, 50, 63,
64]. Moreover, related to the well-known anti-inflamma-
tory effect of adiponectin, it is possible that the reduction
of inflammatory markers is related to the improvement
of insulin sensitivity. Inflammation plays an pivotal role
Table 4 Univariate tests ofsignicance (ANCOVA)
The Δ pre–post for each depended variable group were considered and the baseline values of the outcomes were adopted as covariate; TRF vs ND were assumed as
categorical predictors
Univariate tests ofsignicance (ANCOVA)
Observations Dependent variables
(pre–post Δ) Categorical predictors
(ΔIF vs ΔND) Covariates (baseline
values) P values
Body weight 0.40 ± 1.76 0.97 ± 1.58 vs 0.16 ± 1.78 84.63 ± 6.17 0.0354
FM (kg) 0.96 ± 1.72 1.61 ± 1.53 vs 0.30 ± 1.70 11.12 ± 3.98 0.0070
Adiponectin (μg/mL) 0.45 ± 3.07 2.04 ± 1.52 vs 2.94 ± 1.97 12.83 ± 1.98 0.0000
Leptin (ng/mL) 0.09 ± 0.67 0.36 ± 0.31 vs 0.54 ± 0.64 1.97 ± 0.52 0.0000
IL-6 (ng/L) 0.15 ± 0.27 0.25 ± 0.30 vs 0.04 ± 0.20 1.28 ± 0.31 0.0378
TNF-α (ng/L) 0.14 ± 0.47 0.45 ± 0.37 vs 0.17 ± 0.34 5.63 ± 0.83 0.0000
IL-1β (ng/L) 0.05 ± 0.14 0.12 ± 0.15 vs 0.02 ± 0.09 0.92 ± 0.15 0.0000
Testosterone total (nmol/L) 2.07 ± 3.60 4.40 ± 3.02 vs 0.25 ± 2.43 19.93 ± 6.00 0.0000
IGF-1 (ng/mL) 12.38 ± 33.04 28.00 ± 40.11 vs 3.23 ± 11.13 216.32 ± 38.84 0.0003
Content courtesy of Springer Nature, terms of use apply. Rights reserved.
Page 8 of 10
Moro et al. J Transl Med (2016) 14:290
in insulin resistance development through different
cytokines that influence numerous molecular pathways.
For example, insulin resistance could be triggered by
TNF-α via JNK and IKKβ/NF-κB (jun amino-terminal
kinase/inhibitor of NF-κβ kinase) pathways, which may
increase serine/threonine phosphorylation of insu-
lin receptor substrate 1. Moreover IL-6 could decrease
insulin sensitivity in skeletal muscle by inducing toll-
like receptor-4 (TLR-4) gene expression through STAT3
(activator of transcription 3) activation. is relation-
ship is potentially bidirectional as the activation of IKKβ/
NF-κB signalling could, in turn, stimulate the production
of TNF-α [65]. Modulation of some of these inflamma-
tory markers by IF was seen in the present study: TNF-α
and IL-1β were lower in the TRF group than ND at the
conclusion of the study, while IL-6 appeared to decrease
in the TRF group, but was not significantly different from
ND. Previous information on the impact of IF on inflam-
matory markers is limited, but a previous investigation
by Halberg etal. [66] reported no changes in TNF-α or
IL-6 after two weeks of modified IF in a small sample of
healthy young men.
Although a reduction in T3 was observed in the IF
group, no changes in TSH or resting energy expenditure
were observed. e observed reduction in RR in the TRF
group indicates a very small shift towards reliance on
fatty acids for fuel at rest, although a significant statistical
interaction for RR was not present. Fasting RR has been
previously reported to be a predictor of substantial future
weight gain in non-obese men, with individuals who have
higher fasting RR being more likely to gain weight [67].
Interestingly, it was reported by Seidell et al. [67] that
although RR was related to future weight gain, RMR was
not. It should be noted that individuals with the highest
risk of future weight gain had fasting RR>0.85 (as com-
pared to individuals who had RR<0.76). In the present
study, the RR at the end of the study in both the TRF
group and ND group do not directly fall into either of
these categories (RR=0.81 and 0.83, respectively).
Based on the present study, a modified IF protocol
(i.e. TRF) could be feasible for strength athletes without
negatively affecting strength and muscle mass. Interest-
ingly, even though androgen concentrations were low-
ered by TRF, there was no difference in muscle mass
changes between groups (+0.64kg in TRF vs +0.48kg
in ND). Caloric restriction in rodents has been reported
to decrease testosterone and IGF-1 even though human
data on long-term severe caloric restriction does not
demonstrate a decrease in IGF-1 levels, but instead an
increased serum insulin-like growth factor binding pro-
tein 1 (IGFBP-1) concentration [60, 68]. However, no data
are available for most forms of IF. Decrease the activity
of the IGF-1 axis could be a desirable target for reducing
cancer risk [69], but it is also well known that the activa-
tion of the IGF-1/AKT/mTOR (insulin-like growth fac-
tor-1/protein kinase B/mammalian target of rapamycin)
pathway is one of the keys for muscular growth. In addi-
tion to altering IGF-1, fasting can promote autophagy
[28], which is important for optimal muscle health [70].
Additionally, there is a possibility that the different eating
patterns of the groups in the present study impacted the
relative contributions of different hypertrophic pathways
in each group.
Some limitations of the present study should be taken
into account. One is the different timing of meals in rela-
tionship to the training sessions that could have affected
the subjects’ responses. On this point, there is not a
consensus among researchers. e beneficial effects of
pre-exercise essential amino acid-carbohydrate sup-
plement have been suggested [61], but the same group
found that ingesting 20g of whey protein either before
or 1 h after 10 sets of leg extension resulted in simi-
lar rates of AA uptake [62]. Additionally, other studies
have reported no benefit with pre-exercise AA feeding
[71, 72]. Another limitation of the present study is that
the energy and macronutrient composition of the diet
was based on interview, and this approach has known
weaknesses. Because of the limitations of this method,
it is possible that differences in energy or nutrient intake
between groups could have existed and played a role in
the observed outcomes.
Conclusions
In conclusion, our results suggest that the modified IF
employed in this study: TRF with 16h of fasting and
8h of feeding, could be beneficial in resistance trained
individuals to improve health-related biomarkers,
decrease fat mass, and at least maintain muscle mass.
is kind of regimen could be adopted by athletes dur-
ing maintenance phases of training in which the goal
is to maintain muscle mass while reducing fat mass.
Additional studies are needed to confirm our results
and to investigate the long-term effects of IF and peri-
ods after IF cessation.
Abbreviations
IF: intermittent fasting; TRF: time-restricted feeding; ND: normal diet; ADF:
alternate day fasting; IL-6: interleukin-6; TNF-α: tumor necrosis factor-α; IL-1β:
interleukin-1β; IGF-1: insulin-like growth factor-1; HDL-C: high-density lipopro-
tein cholesterol; LDL-C: low-density lipoprotein cholesterol; TG: triglycerides;
TSH: thyroid-stimulating hormone; T4: free thyroxine; T3: free triiodothyronine;
1-RM: one repetition maximum; REE: resting energy expenditure; RR: respira-
tory ratio; ACC: acetyl-CoA-carboxylase; AMPK: adenosine 5-monophosphate-
activated protein kinase; PGC-1α: Peroxisome proliferator-activated receptor
gamma coactivator 1-alpha; HOMA-IR: homeostasis model assessment–insu-
lin-resistance; mTOR: mammalian target of rapamycin; AKT: protein kinase B;
IGFBP-1: insulin-like growth factor binding protein 1; JNK: jun amino-terminal
kinase; IKKβ/NF-κB: inhibitor of NF-κβ kinase; STAT3: activator of transcription 3;
TLR-4: toll-like receptor-4.
Content courtesy of Springer Nature, terms of use apply. Rights reserved.
Page 9 of 10
Moro et al. J Transl Med (2016) 14:290
Authors’ contributions
TM and AP designed the study. TM, GM, QFP performed the experiment. TM
and AP analysed the data and wrote the manuscript. MN performed nutri-
tional assessment. GB, AB participated in the design of the study and helped
to draft the manuscript. GT and PG helped to draft the manuscript and partici-
pated in the data analysis. All authors read and approved the final manuscript.
Author details
1 Department of Biomedical Sciences, University of Padova, Padua, Italy.
2 Department of Kinesiology & Sport Management, Texas Tech University,
Lubbock, TX, USA. 3 Sport and Exercise Sciences Research Unit, University
of Palermo, Palermo, Italy. 4 Italian Fitness Federation, Ravenna, Italy. 5 College
of Physical Education and Dance, Federal University of Goias, Goiania, Brazil.
Acknowledgements
Not applicable.
Competing interests
The authors declare that they have no competing interests.
Availability of data and materials
The data of the current study are available at request for scientists wishing to
use them with kind full permission.
Ethics approval and consent to participate
All participants read and signed an informed consent document with the
description of the testing procedures approved by the ethical committee of
the Department of Biomedical Sciences, University of Padova (HEC DSB 02/14),
and conformed to standards for the use of human subjects.
Funding
This research was conducted with authors’ institutional founds.
Received: 20 March 2016 Accepted: 3 October 2016
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... This occurs despite the often cited arguments for the importance of consuming breakfast for athletes including blood glucose regulation, energy for performance, improved cognitive functioning, and muscle repair [2,[12][13][14][15]. Indeed, previous investigations have shown decrements in glucose regulation and insulin sensitivity following 2 weeks of breakfast (whole grain cereal) omission [16] and 11 weeks of reducing meals to a single daily 4 h period [15] in lean individuals (BMI < 25 kg/m 2 ) and individuals with type 2 diabetes [17] but not in those with obesity but otherwise healthy [18,19], consuming self-selected items with shorter fasting periods (until noon) [20,21], when combined with exercise [22], or in calorie-restricted states [23]. Similarly, the reduced number of daily protein feedings, and subsequently protein synthetic stimulations, associated with skipping breakfast has been theorized to impair skeletal muscle performance and adaptations [13], which may negatively impact athletic performance. ...
... Furthermore, few investigations have been conducted directly examining the impact of breakfast consumption or omission on longitudinal changes in body composition when combined with exercise. To date, the majority of those conducted have been utilizing variants of IF, most notably, TRE [22,[66][67][68][69][70] or the religious practice of Ramadan [71,72]. While an expansive examination of TRE is beyond the scope of this review and has been thoroughly reviewed elsewhere regarding its impact on changes in body mass [73,74], metabolic health [75], cardiometabolic health [76,77], disease status [78][79][80][81], cognitive function [82], and aging [78], a brief overview is warranted. ...
... However, there are discrepant reports on changes in fat mass. The investigations by Tinsley [67,69] and Moro [22,68] reported those in the TRE groups (i.e., the skipping-breakfast group) lost fat mass, which was either not seen or seen to a lesser extent in the control groups (i.e., consumed breakfast). This is in contrast to the findings of our group [66] in which no differences in changes in body composition were noted regardless of the dietary protocol. ...
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Background: Breakfast is often termed the most important meal of the day. However, its importance to acute and chronic adaptations to exercise is currently not well summarized throughout the literature. Methods: A narrative review of the experimental literature regarding breakfast consumption’s impact on acute and chronic exercise performance and alterations in body composition prior to November 2024 was conducted. To be included in this review, the selected investigations needed to include some aspect of either endurance or resistance training performance and be conducted in humans. Results: These findings suggest that breakfast consumption may benefit acute long-duration (>60 min) but not short-duration (<60 min) morning endurance exercise. Evening time trial performance was consistently inhibited following breakfast omission despite the resumption of eating midday. No or minimal impact of breakfast consumption was found when examining acute morning or afternoon resistance training or the longitudinal adaptations to either resistance or endurance training. Favorable changes in body composition were often noted following the omission of breakfast. However, this was primarily driven by the concomitant reduced kilocalorie intake. Conclusions: Consuming breakfast may aid endurance athletes regularly performing exercise lasting >60 min in length. However, the morning meal’s impact on resistance training and changes in body composition appears to be minimal. Although, as the body of literature is limited, future investigations are needed to truly ascertain the dietary practice’s impact.
... The IF protocol, maintained at 20:4, had no impact on body composition or muscle mass[38]. Interestingly, results were shown by Moro T et al. on a 16:8 IF protocol during resistance training showed that after 8 weeks of exercise, participants experienced a reduction in fat mass while maintaining muscle mass and maximal strength[68]. ...
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Diet plays a significant role in athletes' lives due to its impact on both their performance and health. Gaining a deeper insight into how diet affects athletic outcomes is crucial for designing nutritional strategies that meet the unique demands and goals of each athlete. While a variety of studies have examined different aspects of sports nutrition, there is still a clear need for further investigation in this field. This review examines the effects of alternative dietary approaches, including plant-based diets, ketogenic diets, and intermittent fasting, on athletic health and performance. Drawing on research published from 2014 to 2024, the focus is placed on experimental and systematic studies. The findings suggest that well-planned plant-based diets can deliver notable health benefits, lower the risk of chronic illnesses, and enhance aerobic capacity without hindering performance. In contrast, ketogenic diets, while potentially effective for weight loss, present concerns related to cardiovascular and bone health and may impair performance in high-intensity activities. Intermittent fasting, though showing little impact on resistance training, might negatively affect endurance performance. Overall, plant-based diets stand out as offering the most favorable combination of health advantages and performance support. To enable athletes to make well-informed dietary choices that align with their specific needs, further studies with improved methodologies are essential.
... TRF diminishes pro-inflammatory cytokines by promoting autophagy and improving metabolic health 53 . Studies have shown that TRF may reduce inflammatory biomarkers, such as TNF-α, in individuals with metabolic conditions, contributing to improved liver health and overall metabolic function 54,55 . The LOV-D, rich in anti-inflammatory compounds such as polyphenols, further amplifies this effect by reducing oxidative stress and inhibiting the production of pro-inflammatory cytokines 22 . ...
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Metabolic Associated Fatty Liver Disease (MAFLD) is becoming a major global health concern due to its links with obesity, insulin resistance, and cardiovascular risk. This randomized clinical trial assessed the effects of combining time-restricted feeding (TRF; 16/8) with a Lacto-Ovo-Vegetarian (LOV) diet on various factors in overweight and obese patients with MAFLD. Forty-six participants were randomly assigned to either the intervention group (TRF with LOV diet) or the control group, with 21 participants completing the 12-week study in each group. The intervention group showed significant reductions in weight (-8.07 ± 4.31 kg), BMI (-2.70 ± 1.32 kg/m²), waist circumference (-8.00 ± 4.06 cm), as well as ALT (-17.14 ± 14.33 U/L), GGT (-21.09 ± 24.06 U/L), Fatty Liver Index (-26.90 ± 15.81), insulin levels (-3.89 ± 4.69 mU/L), and TNF-α (-11.85 ± 12.52 pg/mL) compared to the control group (all P < 0.05). Lipid profiles also improved with a reduction in triglycerides (-46.85 ± 54.55 mg/dL) and an increase in HDL-C (3.91 ± 5.07 mg/dL) in the intervention group compared to the control group (P < 0.05). These findings imply that TRF combined with a LOV diet enhances metabolic markers, liver health, and weight loss, thus potentially offering a practical dietary approach for managing MAFLD. Further long-term studies are necessary to validate these results and investigate their clinical applications.
... En otro estudio se reporta que al parecer los japoneses son más susceptibles a acumular grasa visceral con valores bajos de IMC 17,18 . Con todos estos ejemplos queremos mostrar que, si bien es importante tener un parámetro de medición, este no solo debe adaptarse a la población en la que se mide, sino que, debe ser vista en un contexto global laboral (según el puesto que ocupa y la actividad que realiza); para nada se quiere decir que está mal el medir el IMC u otros parámetros fisio-antropométricos, es más, es necesario hacerlo (así como, los programas para que estos se mantengan en un adecuado nivel), pero que estos deberían ser evaluados de forma más integral, derivados de estudios 19,20 . ...
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Introducción: La obesidad y sobrepeso son epidemias globales, que afectan a más de un tercio de la población mundial y su impacto en las actividades de los trabajadores son evaluados en los exámenes médicos ocupacionales. Objetivo: Demostrar la relación entre obesidad y la no aptitud médica ocupacional de los trabajadores en empresas constructoras de Lima entre los años 2011- 2017. Metodología: Estudio transversal analítico, desarrollado en Lima a través de la revisión de los resultados de los exámenes pre-ocupacionales realizados en varios centros médicos para empresas de construcción para diversos puestos laborales. Se obtuvieron estadísticos de asociación de las múltiples asociaciones de la aptitud según la obesidad de los evaluados. Resultados: De los 6398 resultados de exámenes pre ocupacionales. Los que tenían algún grado de obesidad tenían porcentajes de no aptitud que superaban el 97%. Hubo diferencias de las aptitudes entre los que tenían sobrepeso u obesidad según su edad (p<0,001), el colesterol total (p<0,001), el colesterol HDL (p<0,001), el colesterol LDL (p<0,001), los triglicéridos (p<0,001), la glucosa (p<0,001), la presión sistólica (p<0,001), la presión diastólica (p<0,001), las pruebas de esfuerzo (p<0,001), el EKG (p=0,001) y la prueba músculo-esquelética (p<0,001). Conclusión: Si existe relación entre obesidad y razones de la valoración de la no aptitud médica ocupacional de los trabajadores en empresas constructoras de Lima entre los años 2011- 2017.
... Hypothetically, the pre-exercise carbohydrate snack could have reduced the oxygen cost of exercise and reduced the absolute training intensity in the FFG group. However, heart rate data suggests that all groups trained at a similar internal workload ( (Moro et al., 2016;Tinsley et al., 2017;Tinsley & La Bounty, 2015). While speculative, we propose that the fasting groups might have intentionally or unintentionally consumed an excessive number of calories during their feeding windows (i.e., compensatory eating). ...
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Time‐restricted feeding (TRF) and aerobic exercise are lifestyle interventions to prevent or manage different metabolic diseases. How these interventions interact, including the impact of meal timing, is not well understood. The aim of this study was to examine the influence of TRF on fat oxidation during exercise, whereby participants performed an 8‐week fatmax‐training program either in the fasted state or after a carbohydrate‐based snack. 36 participants were randomized into three groups. (1) Training sessions were performed in the fasted state; (2) Training sessions were performed after consuming a standardized carbohydrate‐based snack; (3) Exercise training with an ad libitum diet as a control group. Pre‐ and post‐tests included anthropometric measurements and a fatmax‐cycle‐ergometry protocol to measure substrate oxidation. Data were analyzed as workload‐matched and maximal fat oxidation using a series of mixed ANOVAs. Workload‐matched (p = 0.038) and maximal (p < 0.001) fat oxidation improved in all groups. No significant group × time interactions were found in substrate utilization. Time had a significant effect on body weight (p = 0.011), fat mass (p < 0.001), and muscle mass (p < 0.001). Results suggest that fatmax exercise training leads to improvements in fat oxidative capacity independent of fed or fasted state.
... A recent umbrella review of metaanalyses comparing RCTs of IF to control conditions showed no significant difference in weight or BMI; however, it did show substantial metabolic benefits and a reduction in body fat and waist circumference for IF over the control conditions [18]. A systematic review of RCTs showed no benefits of IF using early time-restricted feeding on energy expenditure [19]; other comparisons of the effect of IF with control diets on energy expenditure in the literature also show no difference; however, they are limited and often involve RCTs in healthy subjects [20,21]. ...
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Background/Objectives: Obesity remains a global health challenge. Many commercial online weight loss programs are available, and they have advantages in terms of scalability and access. Few of these programs have been evaluated for effectiveness in a real-world context. This study reports on the weight loss achieved, platform engagement, and characteristics of successful weight loss predictions in subscribers to the Interval Weight Loss (IWL) program. The Interval Weight Loss program promotes intermittent restricted eating in addition to lifestyle changes in diet composition, exercise, and sleep. Methods: Data for 1705 adults subscribing to the program for >30 days between 2019 and 2024 were included in the analysis. A linear mixed model with polynomial terms was used to model weight loss over time with interaction terms for gender and age. Survival analysis was used to model the proportions and time frame of those meeting 2%, 5%, and 10% weight loss targets and the proportion meeting their goal weight. The focus of the analysis was on the effect at 365 days. Descriptive data from a subset of participants (n = 205) who completed a questionnaire about change in lifestyle habits and mood are also presented. Results: Of those who stayed in the program for at least 365 days, 25.4% achieved their goal weight, 17.6% achieved a 10% weight loss, and 62% achieved a 5% weight loss. By 49 days, 50% had lost 2% of their weight. Significant interactions indicated that males and females in their 60s and 70s were the most responsive to the program. Conclusions: The online commercial Interval Weight Loss platform based on intermittent restricted eating resulted in significant weight loss in a cohort of subscribers in a real-world setting.
... Several studies suggest that intermittent fasting can improve insulin sensitivity, reduce body fat percentage, and lower blood pressure in individuals with obesity. [3] The case highlights the importance of a multidisciplinary lifestyle intervention in achieving sustainable weight loss and improved metabolic health. ...
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This case report explores the weight loss journey of a 26-year-old female achieved through an integrative approach combining Yoga, intermittent fasting, and diet correction. Starting with a BMI of 28.4 kg/m² and weight of 71 kg, the patient underwent a 10-month program designed to improve physical fitness and metabolic health. The intervention resulted in measurable improvements, including an 18.17% reduction in weight, a 17.96% decrease in BMI, and a 15.38% improvement in HbA1c levels. The study demonstrates the effectiveness of a multidisciplinary approach in managing obesity and associated metabolic conditions.
Article
Background The objective of this study was to compare the effects of early time-restricted eating (eTRE) and eTRE plus probiotic supplementation to daily caloric restriction (DCR) alone in terms of biomarkers of oxidative stress (OS), antioxidant capacity, inflammation, and blood pressure (BP) in obese women with polycystic ovary syndrome (PCOS). Materials and Methods The research was conducted as a randomized, parallel, placebo-controlled clinical trial with an 8-week follow-up period. Participants were randomly assigned to one of three groups: 14:10 eTRE with probiotic supplementation ( n = 30), 14:10 eTRE with placebo supplementation ( n = 30), or DCR with placebo supplementation ( n = 30). At the beginning and 8 weeks of the intervention, systolic blood pressure (SBP) and diastolic BP, inflammation, and OS parameters were evaluated. Results A total of 90 participants (mean age, 30.49 years and mean weight, 81.45 kg) were enrolled in this trial. After 8-week intervention, we observed SBP significantly decreased in both the eTRE + probiotic group (−0.31 mmHg [95% confidence interval (CI): −0.55, −0.07]) and the eTRE + placebo group (−0.24 mmHg [95% CI: −0.43, 0.04]), with no significant differences observed between groups. Moreover, C-reactive protein (CRP) levels were significantly reduced in all groups ( P < 0.005). Total antioxidant capacity (TAC) also showed notable improvement in both the eTRE + probiotic group ( P = 0.012) and the DCR group ( P = 0.032). However, there were no significant differences between the three groups regarding BP, OS, TAC, and CRP markers. Conclusion It was not found that eTRE alone or eTRE with probiotics intervention resulted in improving BP, inflammatory, OS, and antioxidant capacity biomarkers than a standard DCR diet among obese women with PCOS. The present study did not reveal significant improvements in BP, inflammatory markers, OS, or antioxidant capacity with either eTRE alone or eTRE combined with probiotics compared to a standard DCR among obese women diagnosed with PCOS. Trial Register no: IRCT20121110011421N5.
Article
Full-text available
Individuals often restrict energy intake to lose fat mass (and body mass [BM]) while performing resistance training (RT) to retain fat-free mass (FFM). Therefore, the aim of the present systematic review with meta-regression was to explore (a) the pattern and strength of the dose-response relationship between daily dietary protein intake and FFM change, and (b) whether intervention duration, energy deficit magnitude, baseline body fat percentage (BF%), and participant sex influence this relationship. Studies were included if they involved a standardized RT protocol with nonobese, energy-restricted (experiencing fat mass loss) individuals with a minimum of 3 months RT experience. Of 916 retrieved studies, data were extracted from a total of 29 studies. Bayesian methods were used to fit linear and nonlinear meta-regression models and estimate effect sizes, highest density credible intervals, and probabilities. Results suggest a >97% probability of a linear dose-response relationship between daily protein intake [g/kgBM: β = 0.07 (95% highest density interval [HDI]: −0.01 to 0.14), and g/kg/FFM: β = 0.06 (95% HDI: 0.01 to 0.12)] and favorable FFM changes. The relationship is stronger when protein intake is expressed relative to FFM, in interventions longer than 4 weeks, in men, and when BF% is lower. Overall, the heterogeneity between studies renders our findings exploratory.
Article
Full-text available
A randomized controlled trial was conducted to examine eight weeks of resistance training (RT) with and without time-restricted feeding (TRF) in order to assess nutrient intake and changes in body composition and muscular strength in young recreationally active males. The TRF programme consisted of consuming all calories within a four-hour period of time for four days per week, but included no limitations on quantities or types of foods consumed. The RT programme was performed three days per week and consisted of alternating upper and lower body workouts. For each exercise, four sets leading to muscular failure between 8 and 12 repetitions were employed. Research visits were conducted at baseline, four, and eight weeks after study commencement. Measurements of total body composition by dual-energy X-ray absorptiometry and muscle cross-sectional area by ultrasound were obtained. Upper and lower body strength and endurance were assessed, and four-day dietary records were collected. TRF reduced energy intake by ∼650 kcal per day of TRF, but did not affect total body composition within the duration of the study. Cross-sectional area of the biceps brachii and rectus femoris increased in both groups. Effect size data indicate a gain in lean soft tissue in the group that performed RT without TRF (+2.3 kg, d = 0.25). Upper and lower body strength and lower body muscular endurance increased in both groups, but effect sizes demonstrate greater improvements in the TRF group. Overall, TRF reduced energy intake and did not adversely affect lean mass retention or muscular improvements with short-term RT in young males.
Article
Full-text available
Young-onset calorie restriction (CR) in rodents decreases serum IGF-1 concentration and increases serum corticosterone levels, which have been hypothesized to play major roles in mediating its anticancer and anti-aging effects. However, little is known on the effects of CR on the IGF-1 system and cortisol in humans. To test the sustained effects of CR on these key hormonal adaptations, we performed a multicenter randomized trial of a 2-year 25% CR intervention in 218 nonobese (body mass index between 22 and 27.8 kg m(-2) ) young and middle-aged (20-50 years age range) men and women. Average CR during the first 6 months was 19.5 ± 0.8% and 9.1 ± 0.7% over the next 18 months of the study. Weight loss averaged 7.6 ± 0.3 kg over the 2-years period of which 71% was fat mass loss (P < 0.0001). Average CR during the CR caused a significant 21% increase in serum IGFBP-1 and a 42% reduction in IGF-1:IGFBP-1 ratio at 2 years (P < 0.008), but did not change IGF-1 and IGF-1:IGFBP-3 ratio levels. Serum cortisol concentrations were slightly but significantly increased by CR at 1 year only (P = 0.003). Calorie restriction had no effect on serum concentrations of PDGF-AB and TGFβ-1. We conclude, on the basis of the present and previous findings, that, in contrast to rodents, humans do not respond to CR with a decrease in serum IGF-1 concentration or with a sustained and biological relevant increase in serum cortisol. However, long-term CR in humans significantly and persistently increases serum IGFBP-1 concentration.
Article
Full-text available
Purpose: The effects of the ketogenic diet (KD) on weight loss, metabolic, and respiratory parameters were investigated in healthy subjects. Methods: Thirty-two healthy subjects were randomized into two groups. The KD group followed a ketogenic diet for 20 days (KD t 0-t 20), then switched to a low-carbohydrate, no-ketogenic diet for 20 days (KD t 20-t 40), and finally was on a Mediterranean diet (MD) for 2 more months (KD t 40-t 2m). The MD group followed a MD for 20 days (MD t 0-t 20), then followed a MD of 1400 kcal over the next 20 days (MD t 20-t 40), and completed the study with the MD for 2 months (MD t 40-t 2m). Body weight, body fat, respiratory rate, and respiratory gas parameters (including respiratory exchange ratio (RER) and carbon dioxide end-tidal partial pressure (PETCO2), oxygen uptake (VO2), carbon dioxide production (VCO2), and resting energy expenditure (REE)) were measured at each point. Results: A significant decrease (p < 0.05) in RER was observed after 20 and 40 days in the KD group, but not in the MD group. In the KD group, significant reductions were observed for both carbon dioxide output and PETCO2, however, there was no significant change in VO2, VCO2, and REE. While both diets significantly decreased body fat mass, the KD diet overall proved to have a higher percentage of fat loss versus the MD diet. Conclusion: The KD may significantly decrease carbon dioxide body stores, which may theoretically be beneficial for patients with increased carbon dioxide arterial partial pressure due to respiratory insufficiency or failure.
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