Three weeks of caloric restriction alters protein metabolism in normal-weight, young men

2005 ◽  
Vol 289 (3) ◽  
pp. E446-E455 ◽  
Author(s):  
Anne L. Friedlander ◽  
Barry Braun ◽  
Margaret Pollack ◽  
Jay R. MacDonald ◽  
Charles S. Fulco ◽  
...  
Keyword(s):  
Caloric Restriction ◽  
Lean Mass ◽  
Nitrogen Balance ◽  
Exercise Performance ◽  
Young Men ◽  
Normal Weight ◽  
Peak Oxygen Consumption ◽  
Whole Body ◽  
Aerobic Performance ◽  
Pool Model

The effects of prolonged caloric restriction (CR) on protein kinetics in lean subjects has not been investigated previously. The purpose of this study was to test the hypotheses that 21 days of CR in lean subjects would 1) result in significant losses of lean mass despite a suppression in leucine turnover and oxidation and 2) negatively impact exercise performance. Nine young, normal-weight men [23 ± 5 y, 78.6 ± 5.7 kg, peak oxygen consumption (V̇o2 peak) 45.2 ± 7.3 ml·kg−1·min−1, mean ± SD] were underfed by 40% of the calories required to maintain body weight for 21 days and lost 3.8 ± 0.3 kg body wt and 2.0 ± 0.4 kg lean mass. Protein intake was kept at 1.2 g·kg−1·day−1. Leucine kinetics were measured using α-ketoisocaproic acid reciprocal pool model in the postabsorptive state during rest and 50 min of exercise (EX) at 50% of V̇o2 peak. Body composition, basal metabolic rate (BMR), and exercise performance were measured throughout the intervention. At rest, leucine flux (≈131 μmol·kg−1·h−1) and oxidation (Rox; ≈19 μmol·kg−1·h−1) did not differ pre- and post-CR. During EX, leucine flux (129 ± 6 vs. 121 ± 6) and Rox (54 ± 6 vs. 46 ± 8) were lower after CR than they were pre-CR. Nitrogen balance was negative throughout the intervention (≈3.0g N/day), and BMR declined from 1,898 ± 262 to 1,670 ± 203 kcal/day. Aerobic performance (V̇o2 peak, endurance cycling) was not impacted by CR, but arm flexion endurance decreased by 20%. In conclusion, 3 wk of caloric restriction reduced leucine flux and Rox during exercise in normal-weight young men. However, despite negative nitrogen balance and loss of lean mass, whole body exercise performance was well maintained in response to CR.

scholarly journals Cardiorespiratory Fitness May Influence Metabolic Inflexibility During Exercise in Obese Persons

2019 ◽  
Vol 104 (12) ◽  
pp. 5780-5790 ◽  
Author(s):  
Francisco J Amaro-Gahete ◽  
Guillermo Sanchez-Delgado ◽  
Ignacio Ara ◽  
Jonatan R. Ruiz
Keyword(s):  
Cardiorespiratory Fitness ◽  
Lean Mass ◽  
Normal Weight ◽  
Whole Body ◽  
Graded Exercise ◽  
Obese Subjects ◽  
Maximal Fat Oxidation ◽  
Metabolic Inflexibility ◽  
Overweight Subjects ◽  
Body Lean Mass

Abstract Context We examined whether obese individuals have a reduced maximal fat oxidation (MFO) and the intensity that elicit MFO (Fatmax) compared with normal weight and overweight persons, taking into account their level of cardiorespiratory fitness. Methods The study subjects were 138 sedentary adults (87 women) aged 30.1 ± 13.6 years. Based on their body mass index, subjects were categorized as being of normal weight (n = 66), overweight (n = 48), or obese (n = 24). MFO and Fatmax were determined for all subjects by indirect calorimetry, using a walking graded exercise test. MFO was expressed in absolute terms (g/min) and relative to whole-body lean mass (mg/kgleanmass/min). Cardiorespiratory fitness was assessed via a maximal treadmill test. Results No differences in absolute MFO and Fatmax values were seen between the obese, normal weight, and overweight subjects (all P > 0.2), although after adjusting for cardiorespiratory fitness, the obese subjects returned significantly higher values than did their normal weight and overweight counterparts (all P < 0.03). However, when expressed with respect to lean mass, the MFO of the normal weight subjects was significantly greater than that of the overweight and obese subjects, independent of age, sex, or cardiorespiratory fitness. Conclusions Obese individuals have higher absolute MFO values when cardiorespiratory fitness is taken into account, but when expressed with respect to lean mass, normal weight individuals show a greater capacity to oxidize fat during exercise per unit of metabolically active tissue independent of age, sex, or cardiorespiratory fitness. These findings suggest that obese individuals may suffer from metabolic inflexibility during exercise.

Endurance training increases fatty acid turnover, but not fat oxidation, in young men

1999 ◽  
Vol 86 (6) ◽  
pp. 2097-2105 ◽  
Author(s):  
Anne L. Friedlander ◽  
Gretchen A. Casazza ◽  
Michael A. Horning ◽  
Anton Usaj ◽  
George A. Brooks
Keyword(s):  
Fatty Acid ◽  
Endurance Training ◽  
Exercise Intensity ◽  
Young Men ◽  
Plasma Free Fatty Acid ◽  
Fat Oxidation ◽  
Peak Oxygen Consumption ◽  
Whole Body ◽  
Plasma Ffa ◽  
Total Fat

We examined the effects of exercise intensity and a 10-wk cycle ergometer training program [5 days/wk, 1 h, 75% peak oxygen consumption (V˙o 2 peak)] on plasma free fatty acid (FFA) flux, total fat oxidation, and whole body lipolysis in healthy male subjects ( n= 10; age = 25.6 ± 1.0 yr). Two pretraining trials (45 and 65% ofV˙o 2 peak) and two posttraining trials (same absolute workload, 65% of oldV˙o 2 peak; and same relative workload, 65% of newV˙o 2 peak) were performed by using an infusion of [1-13C]palmitate and [1,1,2,3,3-2H]glycerol. An additional nine subjects (age 25.4 ± 0.8 yr) were treated similarly but were infused with [1,1,2,3,3-2H]glycerol and not [1-13C]palmitate. Subjects were studied postabsorptive for 90 min of rest and 1 h of cycling exercise. After training, subjects increasedV˙o 2 peak by 9.4 ± 1.4%. Pretraining, plasma FFA kinetics were inversely related to exercise intensity with rates of appearance (Ra) and disappearance (Rd) being significantly higher at 45 than at 65%V˙o 2 peak(Ra: 8.14 ± 1.28 vs. 6.64 ± 0.46, Rd: 8.03 ± 1.28 vs. 6.42 ± 0.41 mol ⋅ kg−1 ⋅ min−1) ( P ≤ 0.05). After training, when measured at the same absolute and relative intensities, FFA Ra increased to 8.84 ± 1.1, 8.44 ± 1.1 and Rd to 8.82 ± 1.1, 8.35 ± 1.1 mol ⋅ kg−1 ⋅ min−1, respectively ( P ≤ 0.05). Total fat oxidation determined from respiratory exchange ratio was elevated during exercise compared with rest, but did not differ among the four conditions. Glycerol Ra was elevated during exercise compared with rest but did not demonstrate significant intensity or training effects during exercise. Thus, in young men, plasma FFA flux is increased during exercise after endurance training, but total fat oxidation and whole-body lipolysis are unaffected when measured at the same absolute or relative exercise intensities.

scholarly journals Intake of Animal Protein Blend Plus Carbohydrate Improves Body Composition With no Impact on Performance in Endurance Athletes

2019 ◽  
Vol 29 (5) ◽  
pp. 474-480
Author(s):  
Fernando Naclerio ◽  
Eneko Larumbe-Zabala ◽  
Mar Larrosa ◽  
Aitor Centeno ◽  
Jonathan Esteve-Lanao ◽  
...  
Keyword(s):  
Body Composition ◽  
Lean Mass ◽  
Orange Juice ◽  
Animal Protein ◽  
Endurance Athletes ◽  
Peak Oxygen Consumption ◽  
Whole Body ◽  
Maximal Aerobic Speed ◽  
The Impact ◽  
Body Lean Mass

The impact of animal protein blend supplements in endurance athletes is scarcely researched. The authors investigated the effect of ingesting an admixture providing orange juice and protein (PRO) from beef and whey versus carbohydrate alone on body composition and performance over a 10-week training period in male endurance athletes. Participants were randomly assigned to a protein (CHO + PRO, n = 15) or a nonprotein isoenergetic carbohydrate (CHO, n = 15) group. Twenty grams of supplement mixed with orange juice was ingested postworkout or before breakfast on nontraining days. Measurements were performed pre- and postintervention on body composition (by dual-energy X-ray absorptiometry), peak oxygen consumption (), and maximal aerobic speed. Twenty-five participants (CHO + PRO, n = 12; CHO, n = 13) completed the study. Only the CHO + PRO group significantly (p < .05) reduced whole-body fat (mean ± SD) (−1.02 ± 0.6 kg), total trunk fat (−0.81 ± 0.9 kg), and increased total lower body lean mass (+0.52 ± 0.7 kg), showing close to statistically significant increases of whole-body lean mass (+0.57 ± 0.8 kg, p = .055). Both groups reduced (p < .05) visceral fat (CHO + PRO, −0.03 ± 0.1 kg; CHO, −0.03 ± 0.5 kg) and improved the speed at maximal aerobic speed (CHO + PRO, +0.56 ± 0.5 km/hr; CHO, +0.35 ± 0.5 km/hr). Although consuming animal protein blend mixed with orange juice over 10 weeks helped to reduce fat mass and to increase lean mass, no additional performance benefits in endurance runners were observed.

scholarly journals The Effect of Repeated Whole-Body Cryotherapy on Sirt1 and Sirt3 Concentrations and Oxidative Status in Older and Young Men Performing Different Levels of Physical Activity

Antioxidants ◽  
2020 ◽  
Vol 10 (1) ◽  
pp. 37
Author(s):  
Gabriela Wojciak ◽  
Jadwiga Szymura ◽  
Zbigniew Szygula ◽  
Joanna Gradek ◽  
Magdalena Wiecek
Keyword(s):  
Physical Activity ◽  
Young Men ◽  
Oxidative Status ◽  
Whole Body ◽  
Stress Index ◽  
Blood Levels ◽  
Long Distance ◽  
Antioxidant Defence ◽  
Whole Body Cryotherapy ◽  
The Impact

Background: The activity of antioxidant enzymes and sirtuins (Sirt) decreases along with age, which is counteracted by aerobic training. Sirtuins increase antioxidant defence. Whole-body cryotherapy (WBC) increases total antioxidant capacity (TAC) in young men. The aim of our study was to assess the impact of 24 WBC treatments on the blood concentration of selected sirtuins and the level of antioxidant defence as well as oxidative stress index of training and non-training men depending on age. Methods: The study involved 40 males. In each group, there were 10 non-training older and young men (60 NTR and 20 NTR), and 10 older and young long-distance runners (60 TR, 20 TR). During an 8-week period, participants underwent 24 WBC treatments (3 min −130 °C), which were performed three times a week (Monday, Wednesday, Friday). The concentrations of Sirt1, Sirt3, TAC, total oxidative status and the activity of superoxide dismutase (SOD), catalase and glutathione peroxidase (GPx) in the blood were determined before 1 WBC and after 1 WBC, 12 WBC and 24 WBC. Results: After 1 WBC, the activity of GPx and the concentration of Sirt1 and TAC in 60 TR and TAC in 60 NTR increased. After 12 WBC, the level of Sirt1 in 20 NTR and SOD in 20 TR increased. After 24 WBC, the level of Sirt1 increased in 60 TR and in 20 NTR, Sirt3 in 60 TR and SOD in 20 TR. Conclusions: Cryogenic temperatures increase blood levels of Sirt1 and Sirt3 and systemic antioxidant defence in men, but the effect is dependent on age, level of performed physical activity and the number of applied treatments.

scholarly journals Acute effect of high-definition and conventional tDCS on exercise performance and psychophysiological responses in endurance athletes: a randomized controlled trial

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Daniel Gomes da Silva Machado ◽  
Marom Bikson ◽  
Abhishek Datta ◽  
Egas Caparelli-Dáquer ◽  
Gozde Unal ◽  
...  
Keyword(s):  
Exercise Performance ◽  
Controlled Trial ◽  
Lower Limbs ◽  
Endurance Athletes ◽  
Test Reliability ◽  
Whole Body ◽  
Time To Exhaustion ◽  
Small Ring ◽  
High Definition ◽  
Psychophysiological Responses

AbstractTranscranial direct current stimulation (tDCS) has been used aiming to boost exercise performance and inconsistent findings have been reported. One possible explanation is related to the limitations of the so-called “conventional” tDCS, which uses large rectangular electrodes, resulting in a diffuse electric field. A new tDCS technique called high-definition tDCS (HD-tDCS) has been recently developed. HD-tDCS uses small ring electrodes and produces improved focality and greater magnitude of its aftereffects. This study tested whether HD-tDCS would improve exercise performance to a greater extent than conventional tDCS. Twelve endurance athletes (29.4 ± 7.3 years; 60.15 ± 5.09 ml kg−1 min−1) were enrolled in this single-center, randomized, crossover, and sham-controlled trial. To test reliability, participants performed two time to exhaustion (TTE) tests (control conditions) on a cycle simulator with 80% of peak power until volitional exhaustion. Next, they randomly received HD-tDCS (2.4 mA), conventional (2.0 mA), or active sham tDCS (2.0 mA) over the motor cortex for 20-min before performing the TTE test. TTE, heart rate (HR), associative thoughts, peripheral (lower limbs), and whole-body ratings of perceived exertion (RPE) were recorded every minute. Outcome measures were reliable. There was no difference in TTE between HD-tDCS (853.1 ± 288.6 s), simulated conventional (827.8 ± 278.7 s), sham (794.3 ± 271.2 s), or control conditions (TTE1 = 751.1 ± 261.6 s or TTE2 = 770.8 ± 250.6 s) [F(1.95; 21.4) = 1.537; P = 0.24; η2p = 0.123]. There was no effect on peripheral or whole-body RPE and associative thoughts (P > 0.05). No serious adverse effect was reported. A single session of neither HD-tDCS nor conventional tDCS changed exercise performance and psychophysiological responses in athletes, suggesting that a ceiling effect may exist.

scholarly journals Effect of oral DHEA on serum testosterone and adaptations to resistance training in young men

1999 ◽  
Vol 87 (6) ◽  
pp. 2274-2283 ◽  
Author(s):  
Gregory A. Brown ◽  
Matthew D. Vukovich ◽  
Rick L. Sharp ◽  
Tracy A. Reifenrath ◽  
Kerry A. Parsons ◽  
...  
Keyword(s):  
Resistance Training ◽  
Young Men ◽  
Serum Testosterone ◽  
Treated Group ◽  
Whole Body ◽  
Total Testosterone ◽  
Resistance Training Program ◽  
Body Resistance ◽  
Liver Transaminases ◽  
And Training

This study examined the effects of acute dehydroepiandrosterone (DHEA) ingestion on serum steroid hormones and the effect of chronic DHEA intake on the adaptations to resistance training. In 10 young men (23 ± 4 yr old), ingestion of 50 mg of DHEA increased serum androstenedione concentrations 150% within 60 min ( P < 0.05) but did not affect serum testosterone and estrogen concentrations. An additional 19 men (23 ± 1 yr old) participated in an 8-wk whole body resistance-training program and ingested DHEA (150 mg/day, n = 9) or placebo ( n = 10) during weeks 1, 2, 4, 5, 7, and 8. Serum androstenedione concentrations were significantly ( P < 0.05) increased in the DHEA-treated group after 2 and 5 wk. Serum concentrations of free and total testosterone, estrone, estradiol, estriol, lipids, and liver transaminases were unaffected by supplementation and training, while strength and lean body mass increased significantly and similarly ( P < 0.05) in the men treated with placebo and DHEA. These results suggest that DHEA ingestion does not enhance serum testosterone concentrations or adaptations associated with resistance training in young men.

scholarly journals MK-677, an Orally Active Growth Hormone Secretagogue, Reverses Diet-Induced Catabolism1

1998 ◽  
Vol 83 (2) ◽  
pp. 320-325 ◽  
Author(s):  
M. G. Murphy ◽  
L. M. Plunkett ◽  
B. J. Gertz ◽  
W. He ◽  
J. Wittreich ◽  
...  
Keyword(s):  
Placebo Group ◽  
Caloric Restriction ◽  
Nitrogen Balance ◽  
Binding Protein ◽  
Growth Hormone Secretagogue ◽  
Significant Difference ◽  
Igf I ◽  
Igf Binding ◽  
Igf Binding Protein ◽  
Orally Active

The reversal of diet-induced negative nitrogen balance by GH suggests a possible therapeutic role for GH treatment in catabolic patients. A double-blind, randomized, placebo-controlled, two-period, cross-over study was designed to investigate whether MK-677, an orally active nonpeptide mimic of GH-releasing peptide, can reverse diet-induced protein catabolism. Eight healthy volunteers (ages 24–39 yr) were calorically restricted (18 kcal/kg·day) for two 14-day periods. During the last 7 days of each diet period, subjects received either oral MK-677 25 mg or placebo once daily. There was a 14- to 21-day washout interval between periods. During the first week of caloric restriction (i.e. diet alone), daily nitrogen losses were similar for both treatment groups (mean ± se; MK-677 group −2.67 ± 0.40 g/day vs. placebo group− 2.83 ± 0.26 g/day). During the second week (diet and study drug), mean daily nitrogen balance was 0.31 ± 0.21 g/day in the MK-677 treatment group compared with −1.48 ± 0.21 g/day in the placebo group (P &lt; 0.01). MK-677 improved nitrogen balance integrated over the 7 days of treatment; area under the curve day 8–14 nitrogen balance response was +2.69 ± 5.0 (se) for MK-677 and −8.97 ± 5.26 g·day for placebo (P &lt; 0.001). MK-677 produced a peak GH response of 55.9 ± 31.7 μg/L after single dose (day 1 of treatment) and 22.6 ± 9.3 μg/L after a week of dosing compared with placebo treatment peak GH values of approximately 9 (treatment day 1) and approximately 7 μg/L (treatment day 7). Following the initial 7-day caloric restriction, insulin-like growth factor-I (IGF-I) declined from 232 ± 25 to 186 ± 19 ng/mL in the MK-677 group and from 236 ± 19 to 174 ± 23 ng/mL in the placebo group. Mean IGF-I concentration increased significantly during MK-677 to 264 ± 31 ng/mL (mean for the last 5 days of treatment) compared with 188 ± 19 ng/mL with placebo (P &lt; 0.01). No significant difference in IGF binding protein-2 was found between the MK-677 and placebo treatments. However, the mean in IGF binding protein-3 for the last 5 days of MK-677 treatment was also significantly increased to 3273 ± 330 ng/mL (mean ± se) compared with placebo 2604 ± 253 ng/mL (P &lt; 0.01). Neither the serum cortisol nor the PRL response was significantly greater after 7 days of MK-677 dosing compared with 7 days of placebo. MK-677 (25 mg) was generally well tolerated and without clinically significant adverse experiences. In conclusion, MK-677 reverses diet-induced nitrogen wasting, suggesting that if these short-term anabolic effects are maintained in patients who are catabolic because of certain acute or chronic disease states, it may be useful in treating catabolic conditions.

scholarly journals Serum betaine is inversely associated with low lean mass mainly in men in a Chinese middle-aged and elderly community-dwelling population

2016 ◽  
Vol 115 (12) ◽  
pp. 2181-2188 ◽  
Author(s):  
Bi-xia Huang ◽  
Ying-ying Zhu ◽  
Xu-ying Tan ◽  
Qiu-ye Lan ◽  
Chun-lei Li ◽  
...  
Keyword(s):  
Lean Mass ◽  
Community Dwelling ◽  
The Body ◽  
Muscle Performance ◽  
Whole Body ◽  
Composition Analysis ◽  
Human Beings ◽  
Middle Aged ◽  
Chinese Adults ◽  
Skeletal Muscle Index

AbstractPrevious studies have demonstrated that betaine supplements increase lean body mass in livestock and improve muscle performance in human beings, but evidence for its effect on human lean mass is limited. Our study assessed the association of circulating betaine with lean mass and its composition in Chinese adults. A community-based study was conducted on 1996 Guangzhou residents (weight/mass: 1381/615) aged 50–75 years between 2008 and 2010. An interviewer-administered questionnaire was used to collect general baseline information. Fasting serum betaine was assessed using HPLC-MS. A total of 1590 participants completed the body composition analysis performed using dual-energy X-ray absorptiometry during a mean of 3·2 years of follow-up. After adjustment for age, regression analyses demonstrated a positive association of serum betaine with percentage of lean mass (LM%) of the entire body, trunk and limbs in men (all P<0·05) and LM% of the trunk in women (P=0·016). Each sd increase in serum betaine was associated with increases in LM% of 0·609 (whole body), 0·811 (trunk), 0·422 (limbs), 0·632 (arms) and 0·346 (legs) in men and 0·350 (trunk) in women. Multiple logistic regression analysis revealed that the prevalence of lower LM% decreased by 17 % (whole body) and 14 % (trunk) in women and 23 % (whole body), 28 % (trunk), 22 % (arms) and 26 % (percentage skeletal muscle index) in men with each sd increment in serum betaine. Elevated circulating betaine was associated with a higher LM% and lower prevalence of lower LM% in middle-aged and elderly Chinese adults, particularly men.

Body Composition, Dietary Intake, and Iron Status of Female Collegiate Swimmers and Divers

2006 ◽  
Vol 16 (3) ◽  
pp. 281-295 ◽  
Author(s):  
Heidi L. Petersen ◽  
C. Ted Peterson ◽  
Manju B. Reddy ◽  
Kathy B. Hanson ◽  
James H. Swain ◽  
...  
Keyword(s):  
Body Composition ◽  
Dietary Intake ◽  
Body Fat ◽  
Lean Mass ◽  
Iron Status ◽  
Dietary Quality ◽  
Whole Body ◽  
Vitamin B ◽  
Percentage Body Fat ◽  
X Ray

This study determined the effect of training on body composition, dietary intake, and iron status of eumenorrheic female collegiate swimmers (n = 18) and divers (n = 6) preseason and after 16 wk of training. Athletes trained on dryland (resistance, strength, fexibility) 3 d/wk, 1.5 h/d and in-water 6 d/wk, nine, 2-h sessions per week (6400 to 10,000 kJ/d). Body-mass index (kg/m2; P = 0.05), waist and hip circumferences (P ≤ 0.0001), whole body fat mass (P = 0.0002), and percentage body fat (P ≤ 0.0001) decreased, whereas lean mass increased (P = 0.028). Using dual-energy X-ray absorptiometry, we found no change in regional lean mass, but fat decreased at the waist (P = 0.0002), hip (P = 0.0002), and thigh (P = 0.002). Energy intake (10,061 ± 3617 kJ/d) did not change, but dietary quality improved with training, as refected by increased intakes of fber (P = 0.036), iron (P = 0.015), vitamin C (P = 0.029), vitamin B-6 (P = 0.032), and fruit (P = 0.003). Iron status improved as refected by slight increases in hemoglobin (P = 0.046) and hematocrit (P = 0.014) and decreases in serum transferrin receptor (P ≤ 0.0001). Studies are needed to further evaluate body composition and iron status in relation to dietary intake in female swimmers.

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