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A High Protein Diet Has No Harmful Effects: A One-Year Crossover Study in Resistance-Trained Males


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The purpose of this investigation was to determine the effects of a high protein diet over a one-year period. Fourteen healthy resistance-trained men completed the study (mean ± SD; age 26.3±3.9 yr; height 178.5±8.4 cm; and average years of training 8.9±3.4 yr). In a randomized crossover design, subjects consumed their habitual or normal diet for 2 months and 4 months and alternated that with a higher protein diet (>3 g/kg/d) for 2 months and 4 months. Thus, on average, each subject was on their normal diet for 6 months and a higher protein diet for 6 months. Body composition was assessed via the Bod Pod ® . Each subject provided approximately 100–168 daily dietary self-reports. During the subjects’ normal eating phase, they consumed (mean ± SD) 29.94±5.65 kcals/kg/day and 2.51±0.69 g/kg/day of protein. This significantly increased ( p<0.05 ) during the high protein phase to 34.37±5.88 kcals/kg/day and 3.32±0.87 g/kg/day of protein. Our investigation discovered that, in resistance-trained men that consumed a high protein diet (~2.51–3.32 g/kg/d) for one year, there were no harmful effects on measures of blood lipids as well as liver and kidney function. In addition, despite the total increase in energy intake during the high protein phase, subjects did not experience an increase in fat mass.
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Research Article
A High Protein Diet Has No Harmful Effects: A One-Year
Crossover Study in Resistance-Trained Males
Jose Antonio, Anya Ellerbroek, Tobin Silver, Leonel Vargas, Armando Tamayo,
Richard Buehn, and Corey A. Peacock
Exercise and Sport Science Laboratory, Nova Southeastern University, Davie, FL, USA
Correspondence should be addressed to Jose Antonio; ja
Received  July ; Accepted  September 
Academic Editor: Michael B. Zemel
Copyright ©  Jose Antonio et al. is is an open access article distributed under the Creative Commons Attribution License,
which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.
e purpose of this investigation was to determine the eects of a high protein diet over a one-year period. Fourteen healthy
resistance-trained men completed the study (mean ±SD; age 26.3 ± 3.9yr; height 178.5 ± 8.4 cm; and average years of training
8.9 ± 3.4 yr). In a randomized crossover design, subjects consumed their habitual or normal diet for  months and  months and
alternated that with a higher protein diet (> g/kg/d) for  months and  months. us, on average, each subject was on their
normal diet for  months and a higher protein diet for  months. Body composition was assessed via the Bod Pod.Eachsubject
provided approximately – daily dietary self-reports. During the subjects’ normal eating phase, they consumed (mean ±SD)
29.94 ± 5.65 kcals/kg/day and 2.51 ± 0.69 g/kg/day of protein. is signicantly increased (𝑝 < 0.05) during the high protein phase
to 34.37 ± 5.88 kcals/kg/day and 3.32 ± 0.87g/kg/day of protein. Our investigation discovered that, in resistance-trained men that
consumed a high protein diet (.–. g/kg/d) for one year, there were no harmfuleectsonmeasuresofbloodlipidsaswellas
liver and kidney function. In addition, despite the total increase in energy intake during the high protein phase, subjects did not
experience an increase in fat mass.
1. Introduction
It has been postulated that the consumption of a high protein
diet may cause harmful eects, particularly in the kidneys.
Approximately a century ago, investigators found “at least
some or very severe” renal damage in a small group of rats on
a high protein diet in which one kidney had been removed [].
Other work on rodents found no evidence of renal damage;
however, they did nd that rats receiving a high protein diet
experienced renal hypertrophy []. Notwithstanding, a more
recent rat study reported that  days of very high whey pro-
tein supplemented diet (i.e.,  human-equivalent  g doses
per day) did not adversely aect blood and/or histological
markers of liver or kidney health and instead may improve
liver health when compared to rats not receiving protein [].
e challenge with determining the eects of high protein
diets on measures of health is the lack of agreement with
what constitutes a “high” intake of protein. At least in athletic
populations, the International Society of Sports Nutrition’s
position stand on protein states that “protein intakes of
.–. g/kg/day for physically active individuals is not only
safe, but may improve the training adaptations to exercise
training” []. Furthermore, scientists have used dierent
denitions of “high” protein intakes. For instance, protein
intakes greater than -% of total energy, as high as %
of total calories, or intakes that exceed the RDA have been
postulated as reaching the threshold of what constitutes a
“high protein” diet []. We would posit that basing a diet on
percentages is misleading. at is, if one were to consume a
hypoenergetic diet of  kcal in which % of the calories
were derived from protein, then that would amount to a
paltry . grams of protein. Instead, high protein diets should
always be dened as the amount of protein consumed per
unit body weight. It is our contention that high protein diets
should necessarily exceed . g/kg/d. Previous work from our
laboratory discovered that an eight-week period of heavy
resistance training coupled with high protein consumption
(>. g/kg/d) results in improvements in body composition
[]. Furthermore, at least in the short term, high protein
Hindawi Publishing Corporation
Journal of Nutrition and Metabolism
Volume 2016, Article ID 9104792, 5 pages
Journal of Nutrition and Metabolism
intakes had no harmful side eects [, ]. However, long-term
longitudinal data are lacking in terms of the eects of high
protein diets. us, the purpose of this investigation was to
examine the eects of high protein consumption in a group
of resistance-trained young males over a -year period.
2. Methods and Materials
2.1. Participants. Fourteen resistance-trained male subjects
volunteered for this investigation (racial/ethnic background:
 white males,  black males, and  Pacic Islander). Subjects
took part in a randomized crossover trial in which they
consumed their habitual (i.e., normal protein) or high protein
diet for two months and four months, respectively. e order
in which they consumed their normal or high protein intakes
was randomized. Subjects followed their normal and high
protein intake phases for a total of  months, respectively.
Subjects came to the laboratory on ve occasions. ey
month periods and two -month periods of following the
respective diet. e extra protein consumed by each subject
was obtained primarily from whey protein powder, which was
provided to each subject at no cost (DymatizeISO- with
 grams of protein,  gram of carbohydrate, and zero grams
of fat per serving of one scoop). However, subjects did not
have to consume the extra protein as powder; instead, they
could consume whatever extra protein source they preferred.
Nova Southeastern University’s Human Subjects Institutional
Review Board in accordance with the Helsinki Declaration
approved this study and written informed consent was
obtained prior to participation.
2.2. Food Diary. Subjects kept a diary (i.e., three days per
app (MyFitnessPal) equaling  daily food logs over the
treatment period. e use of mobile apps for dietary self-
reporting has been previously used [–]. Every subject had
previous experience with this mobile app. e MyFitnessPal
app is a database comprised of over  million foods that
have been provided by users via entering data manually
or by scanning the bar code on packaged goods. us,
the data themselves are primarily derived from food labels
(i.e., nutrition facts panel) derived from the USDA National
Nutrient database.
2.3. Body Composition. Height was measured using standard
anthropometry and total body weight was measured using
a calibrated scale. Body composition was assessed by whole
body densitometry using air displacement via the Bod Pod
(COSMED USA, Concord, CA). All testing was performed
in accordance with the manufacturer’s instructions. Subjects
were instructed to come into the lab aer a -hour fast and no
exercise  hours prior to assessment. ey voided prior to
testing. Subjects were tested while wearing only tight tting
clothing (swimsuit or undergarments) and an acrylic swim
cap. Subjects were instructed to wear the same clothing for
all testing. oracic gas volume was estimated for all subjects
using a predictive equation integral to the Bod Pod soware.
T : Body composition and training volume.
Baseline Normal High
Weight kg . ±. . ±. . ±.
Fat mass kg . ±. . ±. . ±.
FFM kg . ±. . ±. . ±.
% body fat . ±. . ±. . ±.
Volu m e l o a d ,  ±, , ±, , ±
Data are mean ±SD. ere were no signicant dierences between groups.
Volume load is equal to the mean total amount of weight lied (kg) each
Each subject was tested at least twice per visit. Data from
the Bod Pod include body weight, percent body fat, fat-free
mass, and fat mass. All testing was done with each subject
at approximately the same time of day for each of the ve
testing sessions. Although hydration status was not assessed,
investigation. e Bod Pod was calibrated the morning of the
testing session as well as between each subject.
2.4. Blood Analysis: Comprehensive Metabolic Panel and Blood
Lipids. Subjects presented in a fasted state at a local Quest
lipid and comprehensive metabolic panel was done. is
includes the following measures: glucose, blood urea nitrogen
(BUN), creatinine, glomerular ltration rate, BUN/creatinine
ratio, sodium, potassium, chloride, carbon dioxide, calcium,
total protein, albumin, globulin, albumin/globulin ratio, total
bilirubin, alkaline phosphatase, alanine transaminase, aspar-
tate transaminase, total cholesterol, high-density lipoprotein
cholesterol, triglycerides, low-density lipoprotein cholesterol,
and the total cholesterol to high-density lipoprotein choles-
terol ratio. Quest Diagnostics performed each test according
to the standard operating procedure of the company.
2.5. Training Program. Each subject followed their own
strength and conditioning program. e investigators were in
regular contact with each subject to ensure that each subject
completed a training log. e volume load (i.e., total weight
lied per week) was determined for each treatment period.
2.6. Statistics. A -way analysis of variance (ANOVA) was
used to analyze the data with 𝑝 < 0.05 considered as
signicant. e data that were compared were baseline and
the mean of the normal treatment period [combined -
month and -month treatment] as well as the mean of the
high protein treatment period [combined -month and -
month treatment]. Data are expressed as the mean ±SD. e
statistical analysis was completed using Prism  GraphPad
Soware (La Jolla, California).
3. Results
e data for body composition are shown in Table . e
data for nutritional intake are shown in Table . Subjects
consumed more absolute and relative calories and protein
Journal of Nutrition and Metabolism
T : Dietary intake.
Baseline Normal High
Kcal  ±  ±  ±
CHO g  ±  ±  ±
PRO g  ±  ±  ±
Fat g  ±  ±  ±
Kcal/kg/d . ±.     .   ±. . ±.
CHO g/kg/d . ±. . ±. . ±.
PRO g/kg/d . ±. . ±. . ±.
Fat g/kg/d .±. . ±. . ±.
Cholesterol mg  ±  ±  ±
Sodium mg  ±  ±  ±
Sugars g  ±  ±  ±
Fiber g  ±  ±  ±
Data aremean ±SD. Signicant dierence (baseline versus hi gh and normal
versus high; 𝑝 < 0.05).
CHO: carbohydrate, d: day, g: gram, kcal: calorie, kg: kilogram, and PRO:
during the high protein phase (𝑝 < 0.05). ere were no
signicant dierences between the normal and high groups
in any measure of health or body composition (Tables  and
on the high protein phase and only  months on the normal
normal protein phase due to geographic relocation. us, for
this particular subject, we compared the mean of his normal
( months of data) and high protein phases ( months of
4. Discussion
ined the eects of a high protein diet in resistance-trained
subjects over a -year treatment period. In brief, we found
no deleterious eects of a high protein diet (.–. g/kg/d)
over a -year period. Prior work from our lab has shown
that consuming a high protein diet in the short term has no
harmful eects on any clinical measure (i.e., blood lipids and
comprehensive metabolic panel) [, ].
e subjects in the current investigation alternated
between their normal or habitual protein intake and a high
protein intake. It should be noted however that even their
normal protein intake would be considered high by other
investigators [, , ]. us, our study does not support the
notion that protein intakes - times greater than the current
RDA cause any harmful eects.
Moreover, the amount of dietary ber consumed by our
subjects was gramsperday.isisincontrastwiththe
average ber intake in the United States of  grams per
day []. us, it is a falsehood to promote the idea that high
protein diets are mutually exclusive with a diet that is also
high in ber. Our subjects showed no harmful eects of a
hyperenergetic, high protein diet and this (i.e., blood lipids,
renal and hepatic function, etc.) may have been due partially
are associated with a lower risk of cardiovascular disease,
cancer, and all-cause mortality [–]. On the other hand,
the cholesterol intake of our subjects was twice as high as the
typical recommendation of mg per day []. e notion
that high cholesterol intakes have a deleterious eect on blood
lipid markers of cardiovascular disease is not supported by
our data.
Prior work from our laboratory has shown that consum-
ing protein (.–.g/kg/d) in amounts that are - times
greater than the RDA results in a similar FFM increase
the high protein group lost more fat mass compared to the
normal protein group in spite of the fact that they consumed
on average  kcals more per day over the treatment
period. is is in contrast with the current study that showed
no change in body composition. e primary dierence
between the current study and the aforementioned one is
that subjects in the current study did not purposely alter
their training program. On the other hand, subjects in our
previous study were subjected to a dierent training stimulus
(i.e., periodized resistance-training program) than they had
been accustomed to. Inasmuch as the focus on our current
work was on the markers of health, subjects in the current
study were instructed to not alter their training regimen. An
examination of their volume load shows indeed that they did
not make any signicant alterations in training volume. us,
one would speculate that, without signicant changes in the
training stimulus, the mere provision of extra protein would
likely not lead to changes in body composition. Conversely,
the mere addition of extra protein calories also will not lead
to gains in fat mass.
4.1. Limitations. One might speculate that a limitation of
this investigation is that the subjects were young males who
had several years of resistance-training experience and were
regularly consuming a high protein diet at baseline. However,
the fact that they increased their protein intake by %
and still had no deleterious side eects is further evidence
that a high protein diet in exercise-trained individuals is
indeed safe. e small sample size may also preclude one
from applying the results from this study to other populations
(i.e., sedentary men or women). Nonetheless, we would posit
that the only populations that would consume a high protein
diet are athletes (e.g., highly trained endurance and strength-
power athletes). us, the need to apply our data to other
populations may be a moot point.
5. Conclusions
In male subjects with several years of experience with
resistance training, chronic consumption of a diet high in
protein had no harmful eects on any measures of health.
Furthermore, there was no change in body weight, fat mass,
or lean body mass despite eating more total calories and
protein. Contrary to popular belief, the consumption of a
high protein diet is not mutually exclusive with a diet high
in ber nor does the consumption of cholesterol above the
standard recommendations result in any untoward eects on
Journal of Nutrition and Metabolism
T : Blood lipids.
Baseline Normal High Reference range
Total cho l e s t e r o l mg/d L ±  ±  ± –
HDL-C mg/dL  ±  ±  ± >or = 
TG mg/dL  ±  ±  ± <
LDL-C mg/dL  ± ±  ± <
Cholesterol/HDL-C ratio . ±. . ±. . ±. <or = .
Data are mean ±SD. ere were no signicant dierences between groups. C: cholesterol, dL: deciliter, HDL: high-density lipoprotein, LDL: low-density
lipoprotein, mg: milligram, and TG: triglycerides.
T : Comprehensive metabolic panel.
Baseline Normal High Reference range
Glucose mg/dL   ±  ±  ±
BUN mg/dL  ±±±
Creatinine mg/dL . ±. . ±. . ±. .–.
eGFR  ±  ±  ± 
BUN/creatinine ratio  ±±±
Sodium mmol/L  ±±±
Potassium mmol/L . ±. . ±. . ±. .–.
Chloride mmol/L  ±.  ±.  ±. –
CO2mmol/L  ±±±
Calcium mg/dL . ±. . ±. . ±. .–.
Total protein g/dL . ±. . ±. . ±. .–.
Albumin g/dL . ±. . ±. . ±. .–.
Globulin g/dL . ±. . ±. . ±. .–.
Alb/Glob ratio . ±. . ±. . ±. .–.
Total Bili mg/dL . ±. . ±. . ±. .–.
Alkaline phosphatase U/L  ±  ±  ± –
AST U/L  ±±± –
ALT U/L  ±  ±± –
Data are mean ±SD. ere were no signicant dierences between groups. Alb: albumin, ALT: alanine transaminase, AST: aspartate transaminase, Bili:
bilirubin, BUN: blood urea nitrogen, eGFR: estimated glomerular ltration rate, g: grams, Glob: globulin, mmol: millimoles, L: liter, and mg: milligrams. 
indicates a value >or =  mL/min/. m2.
blood lipids. is is the rst -year longitudinal investigation
in resistance-trained males that demonstrates the lack of
harm caused by a high protein diet.
Competing Interests
Jose Antonio Ph.D. is the CEO of the International Society of
Sports Nutrition (ISSN). Dymatize is a sponsor of the ISSN.
All other authors declare that they have no conict of interests
regarding the publication of this paper.
e authors would like to thank Dymatize for providing
protein powder.
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... Other studies have found no detrimental effects of isolated high-protein diets, albeit consumed for relatively brief periods [29,30]. In five healthy resistance-trained men, taking 2.5 ± 1.0 to 3.5 ± 1.4 g/kg/day for 2 years, there was no significant effect on kidney function [29]. ...
... Similarly, in a randomised crossover study in 14 resistance-trained men consuming 2.51-3.32 g/kg/day for one year, no harmful renal effects were observed [30]. In both studies the only parameters reported relating to kidney function were serum creatinine, blood urea nitrogen and eGFR. ...
Full-text available
Bodybuilders routinely engage in many dietary and other practices purported to be harmful to kidney health. The development of acute kidney injury, focal segmental glomerular sclerosis (FSGS) and nephrocalcinosis may be particular risks. There is little evidence that high protein diets and moderate creatine supplementation pose risks to individuals with normal kidney function though long-term high protein intake in those with underlying impairment of kidney function is inadvisable. The links between anabolic androgenic steroid use and FSGS are stronger, and there are undoubted dangers of nephrocalcinosis in those taking high doses of vitamins A, D and E. Dehydrating practices including diuretic misuse, and NSAID use also carry potential risks. It is difficult to predict the effects of multiple practices carried out in concert. Investigations into sub-clinical kidney damage associated with these practices have rarely been undertaken. Future re-search is warranted to identify clinical and subclinical harm associated with individual practices and combinations to enable appropriate and timely advice
... These diets seem to have a direct positive effect on several biological mechanisms, including satiety and energy expenditure increase [11À13]. However, their effects on body composition especially in individuals with obesity or type 2 diabetes are discrepant and controversial [14], mostly regarding the lipidemic profile [15] and liver and kidney function [16]. Several studies have shown that increased amino acid (AA) levels in blood plasma due high-protein diets have been linked with increased odds for hyperinsulinemia, insulin resistance, and type 2 diabetes [17,18]. ...
... After the initial screening of responders, 33 young male [17] and female [16], Caucasian, overweight volunteers fulfilling the inclusion criteria provided their written consent to participate in the study. Three participants (one from each group) were excluded from the study. ...
Objectives: The aim of the present study was to compare the short-term effects of a hypocaloric Mediterranean diet and two high protein diets, with and without whey protein supplementation, on body composition, lipidemic profile, and inflammation and muscle-damage blood indices in overweight, sedentary, young participants. Methods: Thirty-three young, overweight, male and female participants (mean ± SD age: 22.8 ± 4.8 y; body mass: 85.5 ± 10.2 kg; body fat percentage: 34.3% ± 8.1%) were randomly allocated to three different hypocaloric (-700 kcal/d) diets: a Mediterranean diet (MD; n = 10), a high-protein diet (HP; n = 10) diet, and a high-protein diet with whey supplementation (n = 10). The intervention lasted 6 wk. Body composition and biochemical indices were evaluated 1 wk before and after the nutritional interventions. Results: Body and fat mass were decreased in the MD and HP groups (-3.5% ± 1.1% and -5.9% ± 4.2% for body and fat mass respectively in MD, and -1.7% ± 1.2% and -2.0% ± 1.8% for body and fat mass respectively in HP;P < 0.05), with no significant decline of fat-free mass observed in the MD group. The MD group's diet beneficially altered the lipid profile (P < 0.05), but the HP and HPW groups' diets did not induce significant changes. Subclinical inflammation and muscle-damage indices significantly increased in the HP and HPW groups (7.4% ± 3.5% and 66.6% ± 40.1% for neutrophils and CRP respectively in HP, and 14.3% ± 6.4% and 266.6% ± 55.1% for neutrophils and CRP respectively in HPW; P < 0.05) but decreased in the MD group (1.8% ± 1.2% and -33.3% ± 10.1% for neutrophils and CRP respectivelyc; P < 0.05). Energy intake of carbohydrates and proteins were significantly related to the changes in body composition and biochemical blood markers (r = -0.389 and -0.889; P < 0.05). Conclusions: Among the three hypocaloric diets, only the Mediterranean diet induced positive changes in body composition and metabolic profile in overweight, sedentary individuals.
... Regarding ALT and AST (proxy markers of liver health) our null findings align with those of Nieman et al. (60). The lack of changes in eGFR and creatinine in our study is consistent with a plethora of research showing that relatively high protein diets do not have negative effects on renal health in healthy individuals (65)(66)(67) or even in overweight/obese individuals with mild kidney function impairment (68). In brief, both proteins displayed a good safety profile after 8 wks of supplementation, with no changes in inflammatory markers (CRP), red blood cell profile (Hct), liver (ALT/AST), glucose or kidney function (creatinine, eGFR), being observed between groups. ...
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Introduction The effects of dietary protein on body composition and physical performance seemingly depend on the essential amino acid profile of the given protein source, although controversy exists about whether animal protein sources may possess additional anabolic properties to plant-based protein sources. Purpose To compare the effects of a novel plant-based protein matrix and whey protein supplementation on body composition, strength, power, and endurance performance of trained futsal players. Methods Fifty male futsal players were followed during 8 weeks of supplementation, with 40 completing the study either with plant-based protein ( N = 20) or whey protein ( N = 20). The following measures were assessed: bone mineral content, lean body mass, and fat mass; muscle thickness of the rectus femoris; total body water; blood glucose, hematocrit, C-reactive protein, aspartate aminotransferase, alanine aminotransferase, creatine kinase, creatinine, and estimated glomerular filtration rate; salivary cortisol; maximal strength and 1-RM testing of the back squat and bench press exercises; muscle power and countermovement jump; VO 2max and maximal aerobic speed. Subjects were asked to maintain regular dietary habits and record dietary intake every 4 weeks through 3-day food records. Results No differences in any variable were observed between groups at baseline or pre- to post-intervention. Moreover, no time * group interaction was observed in any of the studied variables, and a time effect was only observed regarding fat mass reduction. Conclusions Supplementing with either a novel plant-based protein matrix or whey protein did not affect any of the variables assessed in high-level futsal players over 8 wks. These results suggest that whey protein does not possess any unique anabolic properties over and above those of plant-based proteins when equated to an essential amino acid profile in the population studied. Furthermore, when consuming a daily protein intake >1.6 g/kg ⁻¹ , additional protein supplementation does not affect body composition or performance in trained futsal players, regardless of protein type/source.
... However, protein needs may be higher for athletes completing heavy training to maximize muscle hypertrophy [37]. Additionally, negative effects on kidney function have not been found after consumption of over 3 g protein/kg body weight per day or in subjects consuming~2.5 g protein/kg body weight for 1 year [37,38]. ...
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Once the general public accepts that dietary cholesterol is not a concern for cardiovascular disease risk, foods that have been labeled as high-cholesterol sources, including eggs, may be appreciated for their various other dietary components. One of the nutrients in eggs that deserves further discussion is egg protein. Egg protein has been recognized to be highly digestible and an excellent source of essential amino acids, with the highest attainable protein digestibility-corrected amino acid score. Egg protein has been shown to decrease malnutrition in underdeveloped countries, possibly increase height in children, and protect against kwashiorkor. Egg protein has been demonstrated to be important to skeletal muscle health and protective against sarcopenia. Egg protein also can decrease appetite, resulting in a reduction in the caloric intake from the next meal and weight reduction. Other protective effects of egg protein addressed in this review include protection against infection as well as hypotensive and anti-cancer effects.
... Regarding ALT and AST (proxy markers of liver health) our null findings align with those of Nieman et al. (60). The lack of changes in eGFR and creatinine in our study is consistent with a plethora of research showing that relatively high protein diets do not have negative effects on renal health in healthy individuals (65)(66)(67) or even in overweight/obese individuals with mild kidney function impairment (68). In brief, both proteins displayed a good safety profile after 8 wks of supplementation, with no changes in inflammatory markers (CRP), red blood cell profile (Hct), liver (ALT/AST), glucose or kidney function (creatinine, eGFR), being observed between groups. ...
Conference Paper
INTRODUCTION: Futsal is a demanding team sport that involves strenuous high-intensity bouts of running accelerations and decelerations along with kicking, tackling, turning, changes of direction and repeated sprinting; these demands require high strength and power of the lower limbs. Additionally, like other small-sided games, futsal requires a high level of aerobic capacity (VO2max 55.2 to 62.8 Evidence indicates that protein supplementation enhances muscle strength and hypertrophy, while it may also play a role in muscle repair and recovery from endurance exercise, and further improve VO2max. However, to our knowledge no study has investigated the effects of protein supplementation in futsal players. The purpose of this study was to compare the effects of a novel plant-based protein matrix and whey protein supplementation on body composition, power, and aerobic performance in trained futsal players. Given that both protein sources provided identical amounts of protein and essential amino acids, we hypothesized that changes would be similar between conditions. METHODS: Fifty young (18-35 y) male futsal players from national level futsal clubs volunteered to participate in this 8-week study; forty participants completed the investigation. Participants were randomly assigned to one of two groups: novel plant-based protein (PB) or whey protein (WP). The final sample was comprised of both professional and semi-professional players. Players were assessed for weight (kg), height (cm) and whole-body composition [lean body mass (LBM, kg), absolute and percentage fat mass (FM, kg and %)] using Dual energy X-ray absorptiometry (DXA) according to the procedures recommended by the manufacturer. Anaerobic power was assessed via a supramaximal cycling test – Wingate, performed on a cycle ergometer. Participants were instructed to cycle as fast as possible against a predetermined resistance (7.5% of the participant’s body mass) for 30 s. Aerobic performance was assessed via VO2max determined by a breath-by-breath gas analyzer in an incremental treadmill test. After a 3-minute warm-up at 5 km∙h-1, participants began the test at 6 km∙h-1 and 2% grade. Each minute the speed increased 1 km∙h-1 until volitional exhaustion so that fatigue would be induced within 8-12 minutes. RESULTS: No time or time*group interactions were observed in any of the studied variables (p>0.05) with only a time effect being observed regarding a FM reduction (p<0.05). CONCLUSION: Our results are consistent with some, but not all studies comparing whey protein with plant-based proteins. Methodological and protein matrix differences may account for these discrepancies between studies. Our findings suggest that whey protein does not possess any unique anabolic properties over and above those of plant-based proteins when equated for the essential amino acid profile.
... A VLCKD is characterized by, approximately, a 44-43-13% ratio of lipids, proteins and carbohydrates, respectively, and the total energy intake is less than or equal to 800 kcal [55][56][57][58][59][60]. ...
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A very low-calorie ketogenic diet (VLCKD) is characterized by low daily caloric intake (less than 800 kcal/day), low carbohydrate intake (<50 g/day) and normoproteic (1–1.5 g of protein/kg of ideal body weight) contents. It induces a significant weight loss and an improvement in lipid parameters, blood pressure, glycaemic indices and insulin sensitivity in patients with obesity and type 2 diabetes mellitus. Cushing’s syndrome (CS) is characterized by an endogenous or exogenous excess of glucocorticoids and shows many comorbidities including cardiovascular disease, obesity, type 2 diabetes mellitus and lipid disorders. The aim of this speculative review is to provide an overview on nutrition in hypercortisolism and analyse the potential use of a VLCKD for the treatment of CS comorbidities, analysing the molecular mechanisms of ketogenesis.
... High levels of intramuscular glycogen and the associated intracellular water would thus prevent the loss of ICW that typically accompanies diuresis. Increasing protein intake consumed the day before the show, or simply consuming protein at the high levels typically employed by pre-contest bodybuilders (~3.0-3.5 g/ kg / day; see above) and shown recently to be generally safe over longer periods [110], will encourage greater oxidative deamination of amino acids and ureagenesis [111] that approximate the maximal rates observed in healthy individuals [112,113]. Clearance of blood urea in turn requires an osmotic gradient during its renal excretion, thus causing diuresis [114,115]. ...
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Bodybuilding is a competitive endeavor where a combination of muscle size, symmetry, “conditioning” (low body fat levels), and stage presentation are judged. Success in bodybuilding requires that competitors achieve their peak physique during the day of competition. To this end, competitors have been reported to employ various peaking interventions during the final days leading to competition. Commonly reported peaking strategies include altering exercise and nutritional regimens, including manipulation of macronutrient, water, and electrolyte intake, as well as consumption of various dietary supplements. The primary goals for these interventions are to maximize muscle glycogen content, minimize subcutaneous water, and reduce the risk abdominal bloating to bring about a more aesthetically pleasing physique. Unfortunately, there is a dearth of evidence to support the commonly reported practices employed by bodybuilders during peak week. Hence, the purpose of this article is to critically review the current literature as to the scientific support for pre-contest peaking protocols most commonly employed by bodybuilders and provide evidence-based recommendations as safe and effective strategies on the topic.
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Many studies have evaluated the effects of resistance training (RT) and protein intake to attenuate the age-related loss of skeletal muscle. However, the effects of graded protein intake with conjunctive RT in older adults are unclear. Older adults (n = 18) performed 10 weeks of whole-body RT with progressions to intensity and volume while consuming either a constant protein (CP) diet (0.8–1.0 g/kg/d) with no protein supplement or a graded protein (GP) diet progressing from 0.8 g/kg/d at week 1 to 2.2 g/kg/d at week 10 with a whey protein supplement. Data were collected prior to commencement of the RT protocol (PRE), after week 5 (MID), and after week 10 (POST). Dual Energy X-ray Absorptiometry derived lean/soft tissue mass, ultrasonography derived muscle thickness, and a proxy of muscle quality were taken at PRE and POST, while isokinetic dynamometry derived peak torque were taken at PRE, MID, and POST. This study demonstrated the feasibility of the RT protocol (attendance = 96%), and protein intake protocol (CP in range all weeks; GP deviation from prescribed = 7%). Peak torque, muscle quality scores, and appendicular lean/soft tissue mass demonstrated the main effects of time (p < 0.05) while no other main effects of time or group * time interactions were seen for any measure. In conclusion, RT improved appendicular lean/soft tissue mass, peak torque, and muscle quality, with no differential effects of graded or constant protein intake.
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Athletes and fitness enthusiasts are often encouraged to follow high‐protein diets to optimize muscle protein synthesis, modify body composition, and enhance performance, yet the safety of these higher protein intakes has been debated. Many people with kidney dysfunction are unaware of their condition, and the potential harm of excess protein intake on the kidneys may not be adequately reported in the sports nutrition literature. Studies suggesting that high‐protein intake may be associated with incident kidney disease have led the nephrology community to make conservative recommendations. In contrast, the fitness community suggests that high dietary protein intake is safe and poses no risk of kidney injury. These claims often fail to acknowledge limitations in the internal validity and generalizability of the study results, despite many studies not being adequately powered to support such claims. It is essential to make dietary recommendations that consider the totality of the data and follow the ethical norm of “do no harm.” Studies that evaluate the use of high‐protein diets among athletes must consider the balance of efficacy with safety. While an intervention may be safe in one population, it does not mean that safety can be assumed for all groups.
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Background High-protein (HP) diets have been recommended for weight loss including obese persons. However, the potential effects of HP regimens on kidney health for persons without chronic kidney disease (CKD) are still controversial. Methods To investigate the effects of HP diets versus standard protein/low protein (SP/LP) ones on renal function in individuals without CKD, we conducted this meta-analysis. ResultsThirty-nine RCTs including 3400 participants were considered in this meta-analysis. HP diets resulted in an increased GFR (standardized mean difference [SMD] = 0.64, 95% confidence interval [CI]: 0.03, 1.26) and concentrations of serum urea (MD = 1.05, 95% CI: 0.66, 1.44), creatinine (MD = 2.94, 95% CI: 1.30, 4.58), and uric acid (MD = 19.89, 95% CI: 12.35, 27.43) in obese subjects when compared with SP/LP diets. The results in T2D and health participants did not show a notable detrimental effect on renal outcomes. Subgroup analysis showed that an increase in GFR was presented in obese subjects following an intervention shorter than 6 months. No significant differences were found in the urinary albumin excretion between the HP and SP/LP diets in obese and T2D populations, except for the healthy participants which was reported by only one study.ConclusionsThis meta-analysis showed that HP diets were associated with increased GFR, serum urea, creatinine, and uric acid in obese adults. Future studies are warranted to examine whether resulted glomerular hyperfiltration from HP diet can cause kidney damage in obese individuals.
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Background: Eight weeks of a high protein diet (>3 g/kg/day) coupled with a periodized heavy resistance training program has been shown to positively affect body composition with no deleterious effects on health. Using a randomized, crossover design, resistance-trained male subjects underwent a 16-week intervention (i.e., two 8-week periods) in which they consumed either their normal (i.e., habitual) or a higher protein diet (>3 g/kg/day). Thus, the purpose of this study was to ascertain if significantly increasing protein intake would affect clinical markers of health (i.e., lipids, kidney function, etc.) as well as performance and body composition in young males with extensive resistance training experience. Methods: Twelve healthy resistance-trained men volunteered for this study (mean ± SD: age 25.9 ± 3.7 years; height 178.0 ± 8.5 cm; years of resistance training experience 7.6 ± 3.6) with 11 subjects completing most of the assessments. In a randomized crossover trial, subjects were tested at baseline and after two 8-week treatment periods (i.e., habitual [normal] diet and high protein diet) for body composition, measures of health (i.e., blood lipids, comprehensive metabolic panel) and performance. Each subject maintained a food diary for the 16-week treatment period (i.e., 8 weeks on their normal or habitual diet and 8 weeks on a high protein diet). Each subject provided a food diary of two weekdays and one weekend day per week. In addition, subjects kept a diary of their training regimen that was used to calculate total work performed. Results: During the normal and high protein phase of the treatment period, subjects consumed 2.6 ± 0.8 and 3.3 ± 0.8 g/kg/day of dietary protein, respectively. The mean protein intake over the 4-month period was 2.9 ± 0.9 g/kg/day. The high protein group consumed significantly more calories and protein (p < 0.05) than the normal protein group. There were no differences in dietary intake between the groups for any other measure. Moreover, there were no significant changes in body composition or markers of health in either group. There were no side effects (i.e., blood lipids, glucose, renal, kidney function etc.) regarding high protein consumption. Conclusion: In resistance-trained young men who do not significantly alter their training regimen, consuming a high protein diet (2.6 to 3.3 g/kg/day) over a 4-month period has no effect on blood lipids or markers of renal and hepatic function. Nor were there any changes in performance or body composition. This is the first crossover trial using resistance-trained subjects in which the elevation of protein intake to over four times the recommended dietary allowance has shown no harmful effects.
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Background: The consumption of a high protein diet (>4 g/kg/d) in trained men and women who did not alter their exercise program has been previously shown to have no significant effect on body composition. Thus, the purpose of this investigation was to determine if a high protein diet in conjunction with a periodized heavy resistance training program would affect indices of body composition, performance and health. Methods: Forty-eight healthy resistance-trained men and women completed this study (mean ± SD; Normal Protein group [NP n = 17, four female and 13 male]: 24.8 ± 6.9 yr; 174.0 ± 9.5 cm height; 74.7 ± 9.6 kg body weight; 2.4 ± 1.7 yr of training; High Protein group [HP n = 31, seven female and 24 male]: 22.9 ± 3.1 yr; 172.3 ± 7.7 cm; 74.3 ± 12.4 kg; 4.9 ± 4.1 yr of training). Moreover, all subjects participated in a split-routine, periodized heavy resistance-training program. Training and daily diet logs were kept by each subject. Subjects in the NP and HP groups were instructed to consume their baseline (~2 g/kg/d) and >3 g/kg/d of dietary protein, respectively. Results: Subjects in the NP and HP groups consumed 2.3 and 3.4 g/kg/day of dietary protein during the treatment period. The NP group consumed significantly (p < 0.05) more protein during the treatment period compared to their baseline intake. The HP group consumed more (p < 0.05) total energy and protein during the treatment period compared to their baseline intake. Furthermore, the HP group consumed significantly more (p < 0.05) total calories and protein compared to the NP group. There were significant time by group (p ≤ 0.05) changes in body weight (change: +1.3 ± 1.3 kg NP, -0.1 ± 2.5 HP), fat mass (change: -0.3 ± 2.2 kg NP, -1.7 ± 2.3 HP), and % body fat (change: -0.7 ± 2.8 NP, -2.4 ± 2.9 HP). The NP group gained significantly more body weight than the HP group; however, the HP group experienced a greater decrease in fat mass and % body fat. There was a significant time effect for FFM; however, there was a non-significant time by group effect for FFM (change: +1.5 ± 1.8 NP, +1.5 ± 2.2 HP). Furthermore, a significant time effect (p ≤ 0.05) was seen in both groups vis a vis improvements in maximal strength (i.e., 1-RM squat and bench) vertical jump and pull-ups; however, there were no significant time by group effects (p ≥ 0.05) for all exercise performance measures. Additionally, there were no changes in any of the blood parameters (i.e., basic metabolic panel). Conclusion: Consuming a high protein diet (3.4 g/kg/d) in conjunction with a heavy resistance-training program may confer benefits with regards to body composition. Furthermore, there is no evidence that consuming a high protein diet has any deleterious effects.
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The consumption of dietary protein is important for resistance-trained individuals. It has been posited that intakes of 1.4 to 2.0 g/kg/day are needed for physically active individuals. Thus, the purpose of this investigation was to determine the effects of a very high protein diet (4.4 g/kg/d) on body composition in resistance-trained men and women. Thirty healthy resistance-trained individuals participated in this study (mean ± SD; age: 24.1 ± 5.6 yr; height: 171.4 ± 8.8 cm; weight: 73.3 ± 11.5 kg). Subjects were randomly assigned to one of the following groups: Control (CON) or high protein (HP). The CON group was instructed to maintain the same training and dietary habits over the course of the 8 week study. The HP group was instructed to consume 4.4 grams of protein per kg body weight daily. They were also instructed to maintain the same training and dietary habits (e.g. maintain the same fat and carbohydrate intake). Body composition (Bod Pod®), training volume (i.e. volume load), and food intake were determined at baseline and over the 8 week treatment period. The HP group consumed significantly more protein and calories pre vs post (p < 0.05). Furthermore, the HP group consumed significantly more protein and calories than the CON (p < 0.05). The HP group consumed on average 307 ± 69 grams of protein compared to 138 ± 42 in the CON. When expressed per unit body weight, the HP group consumed 4.4 ± 0.8 g/kg/d of protein versus 1.8 ± 0.4 g/kg/d in the CON. There were no changes in training volume for either group. Moreover, there were no significant changes over time or between groups for body weight, fat mass, fat free mass, or percent body fat. Consuming 5.5 times the recommended daily allowance of protein has no effect on body composition in resistance-trained individuals who otherwise maintain the same training regimen. This is the first interventional study to demonstrate that consuming a hypercaloric high protein diet does not result in an increase in body fat.
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Objective Self-monitoring of physical activity (PA) and diet are key components of behavioral weight loss programs. The purpose of this study was to assess the relationship between diet (mobile app, website, or paper journal) and PA (mobile app vs no mobile app) self-monitoring and dietary and PA behaviors. Materials and methods This study is a post hoc analysis of a 6-month randomized weight loss trial among 96 overweight men and women (body mass index (BMI) 25–45 kg/m2) conducted from 2010 to 2011. Participants in both randomized groups were collapsed and categorized by their chosen self-monitoring method for diet and PA. All participants received a behavioral weight loss intervention delivered via podcast and were encouraged to self-monitor dietary intake and PA. Results Adjusting for randomized group and demographics, PA app users self-monitored exercise more frequently over the 6-month study (2.6±0.5 days/week) and reported greater intentional PA (196.4±45.9 kcal/day) than non-app users (1.2±0.5 days/week PA self-monitoring, p<0.01; 100.9±45.1 kcal/day intentional PA, p=0.02). PA app users also had a significantly lower BMI at 6 months (31.5±0.5 kg/m2) than non-users (32.5±0.5 kg/m2; p=0.02). Frequency of self-monitoring did not differ by diet self-monitoring method (p=0.63); however, app users consumed less energy (1437±188 kcal/day) than paper journal users (2049±175 kcal/day; p=0.01) at 6 months. BMI did not differ among the three diet monitoring methods (p=0.20). Conclusions These findings point to potential benefits of mobile monitoring methods during behavioral weight loss trials. Future studies should examine ways to predict which self-monitoring method works best for an individual to increase adherence.
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The purpose of this study was: aim 1) compare insulin and leucine serum responses after feeding a novel hydrolyzed whey protein (WPH)-based supplement versus a whey protein isolate (WPI) in rats during the post-absorptive state, and aim 2) to perform a thorough toxicological analysis on rats that consume different doses of the novel WPH-based supplement over a 30-day period. In male Wistar rats (~250 g, n = 40), serum insulin and leucine concentrations were quantified up to 120 min after one human equivalent dose of a WPI or the WPH-based supplement. In a second cohort of rats (~250 g, n = 20), we examined serum/blood and liver/kidney histopathological markers after 30 days of feeding low (1human equivalent dose), medium (3 doses) and high (6 doses) amounts of the WPH-based supplement. In aim 1, higher leucine levels existed at 15 min after WPH vs. WPI ingestion (p = 0.04) followed by higher insulin concentrations at 60 min (p = 0.002). In aim 2, liver and kidney histopathology/toxicology markers were not different 30 days after feeding with low, medium, high dose WPH-based supplementation or water only. There were no between-condition differences in body fat or lean mass or circulating clinical chemistry markers following the 30-day feeding intervention in aim 2. In comparison to WPI, acute ingestion of a novel WPH-based supplement resulted in a higher transient leucine response with a sequential increase in insulin. Furthermore, chronic ingestion of the tested whey protein hydrolysate supplement appears safe.
Background: Ad libitum, low-carbohydrate diets decrease caloric intake and cause weight loss. It is unclear whether these effects are due to the reduced carbohydrate content of such diets or to their associated increase in protein intake. Objective: We tested the hypothesis that increasing the protein content while maintaining the carbohydrate content of the diet lowers body weight by decreasing appetite and spontaneous caloric intake. Design: Appetite, caloric intake, body weight, and fat mass were measured in 19 subjects placed sequentially on the following diets: a weight-maintaining diet (15% protein, 35% fat, and 50% carbohydrate) for 2 wk, an isocaloric diet (30% protein, 20% fat, and 50% carbohydrate) for 2 wk, and an ad libitum diet (30% protein, 20% fat, and 50% carbohydrate) for 12 wk. Blood was sampled frequently at the end of each diet phase to measure the area under the plasma concentration versus time curve (AUC) for insulin, leptin, and ghrelin. Results: Satiety was markedly increased with the isocaloric high-protein diet despite an unchanged leptin AUC. Mean (±SE) spontaneous energy intake decreased by 441 ± 63 kcal/d, body weight decreased by 4.9 ± 0.5 kg, and fat mass decreased by 3.7 ± 0.4 kg with the ad libitum, high-protein diet, despite a significantly decreased leptin AUC and increased ghrelin AUC. Conclusions: An increase in dietary protein from 15% to 30% of energy at a constant carbohydrate intake produces a sustained decrease in ad libitum caloric intake that may be mediated by increased central nervous system leptin sensitivity and results in significant weight loss. This anorexic effect of protein may contribute to the weight loss produced by low-carbohydrate diets.
Dietary fiber has been associated with a reduced risk of colorectal cancer. However, it remains unclear at which stage in the carcinogenic pathway fiber may act or which food sources of dietary fiber may be most beneficial against colorectal cancer development. The objective was to prospectively evaluate the association between dietary fiber intake and the risk of incident and recurrent colorectal adenoma and incident colorectal cancer. Study participants were identified from the intervention arm of the Prostate, Lung, Colorectal, and Ovarian Cancer Screening Trial. Participants received flexible sigmoidoscopy at baseline and 3 or 5 y after. Dietary fiber intake was measured by using a self-reported dietary questionnaire. The colorectal cancer, incident adenoma, and recurrent adenoma analyses were based on 57,774, 16,980, and 1667 participants, respectively. Unconditional logistic regression was used to assess the risk of incident and recurrent adenoma, and Cox proportional hazards models were used to assess the risk of colorectal cancer across categories of dietary fiber intake, with adjustment for potential confounders. Elevated total dietary fiber intake was associated with a significantly reduced risk of incident distal colorectal adenoma (ORhighest vs. lowest tertile of intake: 0.76; 95% CI: 0.63, 0.91; P-trend = 0.003) but not recurrent adenoma (P-trend = 0.67). Although the association was not statistically significant for colorectal cancer overall (HR: 0.85; 95% CI: 0.70, 1.03; P-trend = 0.10), a reduced risk of distal colon cancer was observed with increased total fiber intake (HR: 0.62; 95% CI: 0.41, 0.94; P-trend = 0.03). Protective associations were most notable for fiber originating from cereals or fruit. This large, prospective study within a population-based screening trial suggests that individuals consuming the highest intakes of dietary fiber have reduced risks of incident colorectal adenoma and distal colon cancer and that this effect of dietary fiber, particularly from cereals and fruit, may begin early in colorectal carcinogenesis. This trial was registered at as NCT01696981. © 2015 American Society for Nutrition.
Aims: The present meta-analysis aimed to investigate fiber consumption and all-cause mortality, and cause-specific mortality.Methods: Medline and web of science database were searched for cohort studies published from inception to August 2014.Studies were included if they provided a hazard ratio (HR) and corresponding 95% CI for mortality in relation to fiber consumption.Results: Compared with those who consumed lowest fiber, for individuals who ate highest fiber, mortality rate was lower by 23% (HR, 0.77; 95% CI, 0.72-0.81) for CVD, by 17% (HR, 0.83; 95% CI, 0.74- 0.91) for cancer, by 23% (HR, 0.77; 95% CI, 0.73-0.81) for all-cause mortality. For each 10 gram/day increase in fiber intake, the pooled HR was estimated to be 0.89 (95% CI, 0.86-0.93) for all-cause mortality, 0.80 (95% CI, 0.72-0.88) for CHD mortality, and 0.66 (95% CI, 0.40-0.92) for IHD mortality, 0.91 (95% CI, 0.88-0.94) for cancer. Dietary fiber and CVD mortality showed a strong dose-response relation.Conclusions: Fiber consumption is inversely associated with all-cause mortality and CVD, IHD, cancer mortality.This article is protected by copyright. All rights reserved
Dietary fiber may decrease the risk of cardiovascular disease and associated risk factors. We examined trends in dietary fiber intake among diverse US adults between 1999 and 2010, and investigated associations between dietary fiber intake and cardiometabolic risks including metabolic syndrome, cardiovascular inflammation, and obesity. Our cross-sectional analysis included 23,168 men and nonpregnant women aged 20+ years from the 1999-2010 National Health and Nutrition Examination Survey. We used weighted multivariable logistic regression models to estimate predicted marginal risk ratios and 95% confidence intervals for the risks of having the metabolic syndrome, inflammation, and obesity associated with quintiles of dietary fiber intake. Consistently, dietary fiber intake remained below recommended adequate intake levels for total fiber defined by the Institute of Medicine. Mean dietary fiber intake averaged 15.7-17.0 g. Mexican Americans (18.8 g) consumed more fiber than non-Hispanic whites (16.3 g) and non-Hispanic blacks (13.1 g). Comparing the highest with the lowest quintiles of dietary fiber intake, adjusted predicted marginal risk ratios (95% confidence interval) for the metabolic syndrome, inflammation, and obesity were 0.78 (0.69-0.88), 0.66 (0.61-0.72), and 0.77 (0.71-0.84), respectively. Dietary fiber was associated with lower levels of inflammation within each racial and ethnic group, although statistically significant associations between dietary fiber and either obesity or metabolic syndrome were seen only among whites. Low dietary fiber intake from 1999-2010 in the US, and associations between higher dietary fiber and a lower prevalence of cardiometabolic risks suggest the need to develop new strategies and policies to increase dietary fiber intake.
The aim of the present study was to assess the effects of a high protein (HP) and a normal protein (NP) diet on patients with polycystic ovary syndrome (PCOS) and body mass index-matched controls in a sample of southern Brazilian women. This 8-week randomized trial was carried out at a university gynecological endocrinology clinic and included 18 patients with PCOS and 22 controls. Changes in weight, body composition, hormone, and metabolic profile were analyzed in women randomized to receive HP (30% protein, 40% carbohydrate, and 30% lipid) or NP (15% protein, 55% carbohydrate, and 30% lipid). The energy content was estimated for each participant at 20-25 kcal/kg current weight/day. Physical activity, blood pressure, homeostasis model assessment (HOMA) index, and fasting and 2-h glucose and insulin remained stable during the intervention in PCOS and controls, even in the presence of weight loss. There were no changes in lipid profile in either group. In contrast, body weight, body mass index (BMI), waist circumference, percent of body fat, and sum of trunk skinfolds decreased significantly after both diets in both groups. Total testosterone also decreased in PCOS and controls regardless of diet. In conclusion, calorie reduction, rather than protein content, seemed to affect body composition and hormonal profile in this short-term study. These findings emphasize the role of non-pharmacological interventions to reduce weight and ameliorate the anthropometric and clinical phenotype in PCOS.