Determinants of the acetate recovery factor: implications for estimation of [13C]substrate oxidation

2000 ◽  
Vol 98 (5) ◽  
pp. 587-592 ◽  
Author(s):  
Patrick SCHRAUWEN ◽  
Ellen E. BLAAK ◽  
Dorien P. C. van AGGEL-LEIJSSEN ◽  
Lars B. BORGHOUTS ◽  
Anton J. M. WAGENMAKERS
Keyword(s):  
Metabolic Rate ◽  
Body Fat ◽  
Tricarboxylic Acid Cycle ◽  
Substrate Oxidation ◽  
Individual Variability ◽  
Fat Free Mass ◽  
Recovery Factor ◽  
Acid Oxidation ◽  
Percentage Body Fat ◽  
Oxidation Rates

When using 13C or 14C tracers to study substrate metabolism, an acetate correction factor should be applied to correct for loss of label in the exchange pathways of the tricarboxylic acid cycle. We have shown recently that the [13C]acetate recovery factor has a high inter-individual variability and should therefore be determined in every subject. In the present study we examined the factors that might explain some of the variability between subjects in acetate recovery factor. Data were pooled from four different studies with identical protocols, in which the acetate recovery factor was measured, prior to an intervention, to correct plasma fatty acid oxidation rates. Acetate recovery was measured after 2 h of [1,2-13C]acetate infusion at rest followed by 1 h of cycling exercise at 40–50% of maximal oxygen uptake. Inter-individual variance in acetate recovery was 12.0% at rest and 16.1% during exercise. Stepwise regression revealed that, at rest, 37.1% of the acetate recovery could be accounted for by basal metabolic rate adjusted for fat-free mass, percentage body fat and respiratory quotient (RQ). During exercise, 69.1% of the variance in acetate recovery could be accounted for by energy expenditure adjusted for fat-free mass, % body fat and RQ. In conclusion, we show that the acetate recovery factor has a high inter-individual variability, both at rest and during exercise, which can partly be accounted for by metabolic rate, RQ and % body fat. These data indicate that the acetate recovery factor needs to be determined in every subject, under similar conditions as used for the tracer-derived determination of substrate oxidation. Failure to do this might result in large under- or over-estimation of plasma substrate oxidation, and hence to artificial differences between groups.

Effects of carbohydrate ingestion during exercise on substrate oxidation in physically active women with different body compositions

2013 ◽  
Vol 38 (3) ◽  
pp. 314-319 ◽  
Author(s):  
Nicole M. Mitchell ◽  
Jeffery A. Potteiger ◽  
Brittney Bernardoni ◽  
Randal P. Claytor
Keyword(s):  
Body Fat ◽  
Treadmill Exercise ◽  
Maximal Oxygen Consumption ◽  
Substrate Oxidation ◽  
Fat Free Mass ◽  
Physically Active ◽  
Carbohydrate Ingestion ◽  
Oxidation Rates ◽  
Caucasian Women ◽  
Body Compositions

We examined the effects of consuming a 6% carbohydrate (CHO) beverage during exercise on substrate oxidation in active, young Caucasian women with higher body fat (HF) (>25%) and lower body fat (LF) (<25%). The HF group (n = 9) had 32.4% ± 5.6% fat and the LF group (n = 8) had 20.0% ± 3.0% fat. Subjects completed 2 sessions of 45 min of treadmill exercise at 55% of maximal oxygen consumption. Immediately prior to and at 15-min intervals during exercise, subjects consumed 25% of a total volume of a CHO beverage (1 g CHO·kg−1) or a placebo (PLC). During exercise and for 2 h after exercise, expired gases were analyzed to determine oxidation rates for CHO (CHO-OX) and fat (FAT-OX). During exercise, significant differences (p < 0.05) in CHO-OX (mg·kg fat-free mass−1·min−1) were found between groups for the CHO trial (LF, 35.4 ± 4.7 vs. HF, 29.8 ± 3.6) and the PLC trial (LF, 33.7 ± 6.4 vs. HF, 26.3 ± 4.3). CHO-OX was significantly higher during the first hour of recovery in both the LF group (CHO, 9.3 ± 2.1 vs. PLC, 5.3 ± 2.4) and the HF group (CHO, 8.7 ± 2.0 vs. PLC, 4.2 ± 1.0), but during the second hour of recovery, only the HF group had a higher CHO-OX (CHO, 5.3 ± 1.8 vs. PLC, 3.9 ± 1.1). FAT-OX was significantly lower during the first hour of recovery in both the LF group (CHO, 0.6 ± 0.4 vs. PLC, 1.0 ± 0.4) and the HF group (CHO, 0.4 ± 0.4 vs. PLC, 1.4 ± 0.4), as well as during the second hour of recovery in both the LF group (CHO, 0.8 ± 0.4 vs. PLC, 1.3 ± 0.5) and the HF group (CHO, 0.9 ± 0.6 vs. PLC, 1.6 ± 0). CHO ingestion promotes CHO-OX and suppresses FAT-OX during and following exercise in physically active women with low and high levels of body fat.

The Effects of a 20-Week Exercise Training Program on Resting Metabolic Rate in Previously Sedentary, Moderately Obese Women

2001 ◽  
Vol 11 (1) ◽  
pp. 15-31 ◽  
Author(s):  
Heidi K. Byrne ◽  
Jack H. Wilmore
Keyword(s):  
Resistance Training ◽  
Exercise Training ◽  
Metabolic Rate ◽  
Training Program ◽  
Body Fat ◽  
Aerobic Capacity ◽  
Resting Metabolic Rate ◽  
Fat Free Mass ◽  
Obese Women ◽  
Resistance Training Program

The present study was designed to investigate the effects of exercise training on resting metabolic rate (RMR) in moderately obese women. It was hypothesized that exercise training would increase resting metabolic rate. Nineteen previously sedentary, moderately obese women (age = 38.0 ± 0.9 years, percent body fat = 37.5 ± 0.8) trained for 20 weeks using either resistance training (RT) or a combination of resistance training arid walking (RT/W). The high intensity resistance training program was designed to increase strength and fat-free mass and the walking program to increase aerobic capacity. There was also a non-exercising control group (C) of 9 subjects in this study. Fat-free mass was significantly increased in both the RT (+1.90 kg) and RT/W (+1.90 kg) groups as a result of the training program. No group showed significant changes in fat mass or relative body fat from pre- to post-training. Aerobic capacity was slightly, though significantly, increased in the RT/W group only. The RT group showed a significant increase (+44 kcal · day−1), while the RT/W group showed a significant decrease (-53 kcal · day−1) in resting metabolic rate post-training. RT can potentiate an increase in RMR through an increase in fat-free mass, and the decrease in RMR in the RT/W group may have been a result of heat acclimation from the walk training.

Impact of body fat mass and percent fat on metabolic rate and thermogenesis in men

1989 ◽  
Vol 256 (5) ◽  
pp. E573-E579 ◽  
Author(s):  
K. R. Segal ◽  
I. Lacayanga ◽  
A. Dunaif ◽  
B. Gutin ◽  
F. X. Pi-Sunyer
Keyword(s):  
Metabolic Rate ◽  
Body Fat ◽  
Fat Mass ◽  
Resting Metabolic Rate ◽  
Fat Free Mass ◽  
Body Fat Mass ◽  
Thermic Effect Of Food ◽  
Group A ◽  
Effect Of Food ◽  
Thermic Effect

To clarify further the independent relationships of body composition parameters to energy expenditure, resting metabolic rate (RMR) and postprandial thermogenesis were studied in four groups who were matched for absolute fat mass (study 1) and relative fatness (study 2). In study 1, five lean [group A, 15.4 +/- 0.6% (+/- SE) body fat] and five obese men (group B, 25.0 +/- 0.9% fat) were matched on body fat mass (13.0 +/- 0.9 vs. 14.4 +/- 0.8 kg, respectively). Fat-free mass (FFM) and total weight were greater for group A than B. RMR was measured for 3 h in the fasted state and after a 720-kcal mixed meal. RMR was greater for group A than B (1.38 +/- 0.08 vs. 1.14 +/- 0.04 kcal/min, P less than 0.05). The thermic effect of food, calculated as 3 h postprandial minus fasting RMR, was greater for group A than B (65 +/- 6 vs. 23 +/- 9 kcal/3 h; P less than 0.05). In study 2, two groups (n = 6 men/group) were matched for percent body fat (33 +/- 1% fat for both) but differed in lean, fat, and total weights: 50.8 +/- 3.1 kg FFM for the lighter (group C) vs. 68.0 +/- 2.8 kg FFM for the heavier (group D) group, P less than 0.05. RMR was lower for group C than D (1.17 +/- 0.06 vs. 1.33 +/- 0.04 kcal/min, P less than 0.05), but the thermic effect of food was not significantly different (31 +/- 3 vs. 20 +/- 6 kcal/3 h).(ABSTRACT TRUNCATED AT 250 WORDS)

scholarly journals Ethnic differences in the relationship between body mass index and percentage body fat among Asian children from different backgrounds

2011 ◽  
Vol 106 (9) ◽  
pp. 1390-1397 ◽  
Author(s):  
Ailing Liu ◽  
Nuala M. Byrne ◽  
Masaharu Kagawa ◽  
Guansheng Ma ◽  
Bee Koon Poh ◽  
...  
Keyword(s):  
Body Composition ◽  
Body Fat ◽  
Ethnic Differences ◽  
Task Force ◽  
The Philippines ◽  
Overweight And Obesity ◽  
Fat Free Mass ◽  
Percentage Body Fat ◽  
Asian Children ◽  
The Relationship

Overweight and obesity in Asian children are increasing at an alarming rate; therefore a better understanding of the relationship between BMI and percentage body fat (%BF) in this population is important. A total of 1039 children aged 8–10 years, encompassing a wide BMI range, were recruited from China, Lebanon, Malaysia, The Philippines and Thailand. Body composition was determined using the 2H dilution technique to quantify total body water and subsequently fat mass, fat-free mass and %BF. Ethnic differences in the BMI–%BF relationship were found; for example, %BF in Filipino boys was approximately 2 % lower than in their Thai and Malay counterparts. In contrast, Thai girls had approximately 2·0 % higher %BF values than in their Chinese, Lebanese, Filipino and Malay counterparts at a given BMI. However, the ethnic difference in the BMI–%BF relationship varied by BMI. Compared with Caucasian children of the same age, Asian children had 3–6 units lower BMI at a given %BF. Approximately one-third of the obese Asian children (%BF above 25 % for boys and above 30 % for girls) in the study were not identified using the WHO classification and more than half using the International Obesity Task Force classification. Use of the Chinese classification increased the sensitivity. Results confirmed the necessity to consider ethnic differences in body composition when developing BMI cut-points and other obesity criteria in Asian children.

Anthropometrics of Italian Senior Male Rugby Union Players: From Elite to Second Division

2015 ◽  
Vol 10 (6) ◽  
pp. 674-680 ◽  
Author(s):  
Federico Y. Fontana ◽  
Alessandro Colosio ◽  
Gabriela F. De Roia ◽  
Giorgio Da Lozzo ◽  
Silvia Pogliaghi
Keyword(s):  
Body Fat ◽  
Characteristic Curve ◽  
National Level ◽  
Rugby Union ◽  
Fat Free Mass ◽  
Reference Database ◽  
Cross Sectional ◽  
Percentage Body Fat ◽  
National Team ◽  
Rugby Players

Anthropometric evaluation of athletes is necessary to optimize talent identification and player development. Objectives: To provide a specific anthropometric reference database of senior male rugby players competing at different levels in the southern European region. Design: Cross-sectional. Methods: In 362 professional players (25 ± 4 y; 138 Italian national team, 97 first-division, and 127 second-division national championships) the authors measured mass, stature, and percentage body fat (plicometry). Mean, SD, and coefficient of variation were calculated for forwards and backs and for positional subgroups. Binomial logistic regression and receiver-operating-characteristic curve were performed to assess which variables best predicted level assignment (international vs national level). Results: For all competitive levels forwards were significantly heavier and taller and had a larger percentage body fat and fat-free mass than backs. The lower the competitive level, the higher the within-role variability observed; furthermore, players in a specific positional subgroup were lighter, shorter, and fatter and had less fat-free mass. Fat-free mass is the variable that best predicts the likelihood of being classified as an international or national player (cutoff value 79.54 kg). Conclusions: The data confirm the specificity in the physical requirements of rugby in individual playing positions at all competitive levels and document significant differences among elite and 1st- and 2nd-division players in the same positional role. These differences may reflect the variable technical abilities, selection, training practices, and requirements of the game among these categories.

Abstract P125: Multiple Measures of Energy Expenditure and Substrate Oxidation in Non-obese White and African American Young Adults

Circulation ◽  
2018 ◽  
Vol 137 (suppl_1) ◽  
Author(s):  
Peter T Katzmarzyk ◽  
Eric Ravussin
Keyword(s):  
Physical Activity ◽  
Energy Expenditure ◽  
Fat Oxidation ◽  
Substrate Oxidation ◽  
Activity Level ◽  
Fat Free Mass ◽  
Free Living ◽  
Multiple Measures ◽  
Oxidation Rates ◽  
Increased Risk

Introduction: African Americans (AA) experience higher rates of obesity and related disorders than the general U.S. population. It has been hypothesized that the increased risk of obesity among AA may be explained, in part, by lower levels of energy expenditure (EE) and lower levels of fat oxidation. However, many different measures of EE and substrate oxidation have been employed across previous studies. Objective: The objective of this study was to compare multiple measures of EE and substrate oxidation among White (W) and AA adults. We hypothesize that AA will have lower EE and lower fat oxidation rates than W. Methods: A sample of 12 young (ages 22 to 35 y), non-obese AA adults was recruited from the local community and pair-matched by age, sex and body mass index (BMI) to a sample of 12 W adults. Height and weight were measured and BMI was calculated (kg/m 2 ). Total fat mass (FM) and fat free mass (FFM) were measured using dual energy x-ray absorptiometry. Resting EE (REE) and respiratory quotient (RQ) were measured in a fasting state using a metabolic cart; 24-hour EE, 24-h RQ, sleep EE and sleep RQ were measured in a whole room calorimeter; and free-living total daily EE (TDEE) was measured over two weeks using doubly labelled water. Physical activity level (PAL) was computed as TDEE/REE. Differences between W and AA were determined using general linear models, adjusting for FFM. Results: The analytic sample had a mean age of 27.0 y (SD 4.3 y) and mean BMI of 22.9 kg/m 2 (SD 2.9 kg/m 2 ). There were no significant differences in age, BMI, FM or FFM between W and AA (all p>0.05). However, W had significantly higher REE (1459 vs 1305 kcal/day; p=0.001), 24-h EE (1826 versus 1737 kcal/day; p=0.02), sleep EE (1509 vs 1405 kcal/day; p=0.005); but not TDEE (2452 vs 2313 kcal/day; p=0.30) compared to AA. There were no race differences in RQ (0.83 vs 0.83; p=0.93), 24-h RQ (0.86 vs 0.88; p=0.24) or sleep RQ (0.86 vs 0.87; p=0.44). On the other hand, AA had higher PAL (1.34 vs 1.26; p=0.04) compared to W. Conclusions: Non-obese W adults demonstrated higher REE, 24-h EE, and sleep EE compared to AA, but had similar levels of free-living TDEE. It appears as though some AA adults may compensate for lower REE by increased physical activity, which may be an effective strategy to prevent weight gain and obesity.

Pattern of Amino Acid Oxidation in Low BMI South Indian Pregnant Women

2016 ◽  
Vol 53 (2) ◽  
pp. 153
Author(s):  
Pauline Anand ◽  
Pratibha Dwarkanath ◽  
Tinku Thomas ◽  
Anura V. Kurpad
Keyword(s):  
Amino Acid ◽  
Pregnant Women ◽  
Body Fat ◽  
Early Pregnancy ◽  
Acid Oxidation ◽  
Maternal Body ◽  
Amino Acid Oxidation ◽  
Leucine Oxidation ◽  
Oxidation Rates ◽  
Low Bmi

It is not known whether Indian pregnant women with low Body Mass Index (BMI) have adequate protein stores to provide sufficient amino acids for the growing fetus and how this interacts with the maternal body fat (energy) stores in early pregnancy. This study aimed to measure amino acid oxidation in pregnant women with low BMI and to evaluate the influence of maternal body fat on amino acid oxidation in early pregnancy. In two experimental studies of low BMI women, leucine oxidation rates significantly reduced from 1<sup>st</sup> to 3<sup>rd</sup> trimester (post absorptive state, p&lt;0.002 and fed state, p&lt;0.003, Wilcoxon sign rank test). In the post absorptive state in the 1st trimester, leucine oxidation negatively correlated with maternal fat percentage (r=-0.32, p=0.04). Hence, it would appear that the availability of body fat as an energy store in early pregnancy could reduce the utilization of amino acid as a substrate for the energy demands of the growing feto-placental unit.

Intra-Season Changes in Open-Class Amateur Boxers’ Physiological Profiles: A Yearlong Study

2017 ◽  
Vol 2 (8) ◽  
pp. 117-121
Author(s):  
Philip Davis
Keyword(s):  
Body Mass ◽  
Body Fat ◽  
Fat Free Mass ◽  
Upper Body ◽  
Fat Percentage ◽  
Percentage Body Fat ◽  
Training Strategy ◽  
Diet Control ◽  
Run Up ◽  
Open Class

Introduction. Little is known of the physiological trainability of boxers and their reactions to current training strategy. Material and methods. Anthropometric, back/hand strength, upper-body plyometric power and 3x3 min running parameters were measured four times throughout the year and maximal oxygen uptake () at peak season. In twelve male open-class boxers (mean ± standard deviation) age: 22.7±2.7 yrs, height: 177.2±9.4 cm and body mass: 72.1±10.7 kg. Results. Surprisingly body mass, body fat, percentage body fat and total run distance showed no improvement throughout the season until peak season (all p<.002), 72.1 kg, 8.4 kg, 11.5 %, and 2548 m respectively. However this appeared to be at the expense of fat free mass which decreased by ~2 kg at peak season (p=.014). Furthermore, improvement beyond the starting le­vels at the start of the season for all parameters was never achieved. The results suggest that despite coach and boxer best efforts, training per-se does not necessarily result in the desired improvements. Conclusion. It is advised that boxers maintain a level of diet-control/training during holiday periods, this will allow the run-up to peak season to be about a controlled decrease of BF and maintenance or increase of fat free mass, strength and power. A simple set of tests should be used to track progress and identify areas that need improving. Strength, plyometric and individualisation of training should be implemented to improve the boxers’ speed and power-endurance.

Muscle mitochondrial morphology, body composition, and energy expenditure in sedentary individuals

1991 ◽  
Vol 260 (1) ◽  
pp. E89-E94 ◽  
Author(s):  
S. P. Kirkwood ◽  
F. Zurlo ◽  
K. Larson ◽  
E. Ravussin
Keyword(s):  
Energy Expenditure ◽  
Metabolic Rate ◽  
Body Fat ◽  
Vastus Lateralis ◽  
Oxidative Capacity ◽  
Fat Free Mass ◽  
Mitochondrial Morphology ◽  
Thigh Circumference ◽  
Wide Range

To investigate whether differences in metabolic rate are related to differences in muscle mitochondrial morphology and/or to differences in in vitro muscle respiration, we studied 17 healthy Caucasians, covering a wide range of body weight and composition [9 males, 8 females; body wt 96 +/- 37 (SD) kg; body fat = 28 +/- 10%]. Central and peripheral mitochondrial volume density (Vmit c and Vmit p, respectively) and the ratio of mitochondrial outer surface to volume of mitochondria (SVmit c in center and SVmit p at periphery) were determined by stereological analyses of transmission electron micrographs from samples of the vastus lateralis. There was no relationship between mitochondrial morphology or muscle respiration and 24-h energy expenditure, basal metabolic rate, or sleeping energy expenditure adjusted for differences in fat-free mass, fat mass, age, and sex. Although total body fat was not associated with muscle cell morphology, central distribution of body fat [waist-to-thigh circumference ratio (W/T)] correlated negatively with Vmit c (r = -0.58, P = 0.01), SVmit c (r = -0.59, P = 0.01), and SVmit p (r = -0.48, P = 0.05). W/T was also negatively related to muscle respiration (r = -0.59, P = 0.01). Despite the lack of relationship between metabolic rate and muscle mitochondrial morphology, central distribution of body fat is associated with lower mitochondrial density and larger mitochondria in skeletal muscle and is associated with a decreased oxidative capacity of muscle.

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