scholarly journals Computational model of in vivo human energy metabolism during semistarvation and refeeding

2006 ◽  
Vol 291 (1) ◽  
pp. E23-E37 ◽  
Author(s):  
Kevin D. Hall
Keyword(s):  
Body Weight ◽  
Metabolic Rate ◽  
Body Fat ◽  
Fat Mass ◽  
De Novo ◽  
Resting Metabolic Rate ◽  
De Novo Lipogenesis ◽  
Experimental Measurements ◽  
Metabolic Fluxes

Changes in body weight and composition are the result of complex interactions among metabolic fluxes contributing to macronutrient balances. To better understand these interactions, a mathematical model was constructed that used the measured dietary macronutrient intake during semistarvation and refeeding as model inputs and computed whole body energy expenditure, de novo lipogenesis, and gluconeogenesis as well as turnover and oxidation of carbohydrate, fat, and protein. Published in vivo human data provided the basis for the model components that were integrated by fitting a few unknown parameters to the classic Minnesota human starvation experiment. The model simulated the measured body weight and fat mass changes during semistarvation and refeeding and predicted the unmeasured metabolic fluxes underlying the body composition changes. The resting metabolic rate matched the experimental measurements and required a model of adaptive thermogenesis. Refeeding caused an elevation of de novo lipogenesis that, along with increased fat intake, resulted in a rapid repletion and overshoot of body fat. By continuing the computer simulation with the prestarvation diet and physical activity, the original body weight and composition were eventually restored, but body fat mass was predicted to take more than one additional year to return to within 5% of its original value. The model was validated by simulating a recently published short-term caloric restriction experiment without changing the model parameters. The predicted changes in body weight, fat mass, resting metabolic rate, and nitrogen balance matched the experimental measurements, thereby providing support for the validity of the model.

Abstract P293: Resting Metabolic Rate, Cardiorespiratory Fitness, and Racial Differences in Adiposity among Adult Women

Circulation ◽  
2013 ◽  
Vol 127 (suppl_12) ◽  
Author(s):  
Robin P Shook ◽  
Gregory A Hand ◽  
Amanda E Paluch ◽  
James R Hebert ◽  
Xuewen Wang ◽  
...  
Keyword(s):  
Body Weight ◽  
Energy Expenditure ◽  
Metabolic Rate ◽  
Cardiorespiratory Fitness ◽  
Body Fat ◽  
Fat Mass ◽  
Resting Metabolic Rate ◽  
Overweight And Obesity ◽  
Vigorous Activity

Background: African American (AA) adult females have a higher prevalence of overweight and obesity compared to their Caucasian (Cauc) peers. Lower resting metabolic rate (RMR) values, a hypothesized contributor to higher levels of adiposity, have been observed among AA women. However, it is unknown whether cardiorespiratory fitness (CRF) is associated with RMR in this population. Methods: Sixty-two overweight/obese (body mass index [BMI] ≥25.0) yet healthy women (42 Cauc, 20 AA) between the ages of 21-35 years were recruited for the present study. RMR was measured using a ventilated hood system. Participants arrived fasted for at least 12 hrs and having refrained from alcohol/exercise for at least 24 hrs. Participants rested in a supine position for 30-minutes, followed by a 30-minute RMR gas collection period. Body weight (BW) and height were measured and body fat (BF) was calculated as the percentage of total weight identified as fat tissue by dual x-ray absorptiometry. CRF was measured via a metabolic cart during a modified Bruce treadmill protocol. Total energy expenditure (TEE) was assessed using an arm-based physical activity monitor worn at all times for 10 consecutive days. Energy intake (EI) was assessed over a 14-day period via interviewer-administered dietary recall. Results: Cauc and AA participants were similar in terms of age (27.6±4.2 years), weight (79.9±9.9 kg), BMI (29.4±2.9 kg/m2), body fat percentage (41.0±5.1 percent), and EI (1760±397 kcal/day). Compared to Cauc, AA women were slightly shorter (162.4±7.0 vs. 165.8±5.1 cm, p=0.0371), lower CRF (27.4±3.8 vs. 31.4±5.2 ml/kg/min, p=0.0032), lower TEE (2438±264 vs. 2598±303 kcal/day, p=0.0102) and lower RMR (1436±222 vs. 1569±181 kcal/day, p=0.0154). Energy expenditure resulting from moderate/vigorous activity was higher in Cauc females (552±386 vs. 355±197 kcal/day, p=0.0102). RMR was correlated with fat mass, CRF and race. After adjustment for age, race, body weight, fat-free mass, fat mass, and CRF, the least squares means for RMR remained lower in AA compared to Cauc (1444 vs. 1565 kcal/day, p=0.0034) and was only significantly related race (p=0.0034). Conclusion: The results of this study confirm previous research reporting lower RMR values among AA females compared to their Cauc counterparts, though these differences did not result in variations of adiposity. The current analyses suggest CRF plays an important role in the determination of RMR. The differences among racial groups in energy expenditure resulting from moderate/vigorous activity may play a key role in the determination of CRF and ultimately RMR.

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 The contributions of hepatic de novo lipogenesis to the difference in body fat mass of genetically lean and fat duck breeds

2017 ◽  
Vol 46 (1) ◽  
pp. 845-853
Author(s):  
Hehe Liu ◽  
Junying Liu ◽  
Tianyu Zhou ◽  
Guosong Wang ◽  
Kai Lu ◽  
...  
Keyword(s):  
Body Fat ◽  
Fat Mass ◽  
De Novo ◽  
De Novo Lipogenesis ◽  
Body Fat Mass ◽  
The Difference

scholarly journals Is resting metabolic rate different between men and women?

2001 ◽  
Vol 86 (6) ◽  
pp. 641-646 ◽  
Author(s):  
Andrea C. Buchholz ◽  
M. Rafii ◽  
P. B. Pencharz
Keyword(s):  
Metabolic Rate ◽  
Body Fat ◽  
Fat Mass ◽  
Resting Metabolic Rate ◽  
Cell Mass ◽  
Open Circuit ◽  
Men And Women ◽  
Adult Men ◽  
Total Body ◽  
Composition Factors

A low resting metabolic rate (RMR) has been proposed as a possible cause for the increased body fat commonly seen in women compared with men. Absolute RMR is higher in men, but whether RMR adjusted for lean body mass (LBM) remains higher is unresolved. The objective of the present study was to determine whether RMR adjusted for various body composition factors differed between healthy adult men and women. Thirty men (28·3±8·0 years, BMI 23·7±2·1 kg/m2) and twenty-eight women (28·7±6·9 years, BMI 22·2±1·9 kg/m2) were included in the analyses. RMR was measured by open-circuit indirect calorimetry for 60 min. Extracellular water (ECW) was measured by corrected Br- space and total body water (TBW) by 2H dilution. LBM was estimated as TBW/0·732. Intracellular water (ICW) was calculated as TBW-ECW, and body cell mass (BCM) as ICW/0·732. Men were heavier and had higher BMI, LBM, BCM and ECW, but less fat mass. Absolute RMR was higher in men than women (7280±844 v. 5485±537 kJ/d, P<0·0001). This difference became non-significant when RMR was adjusted for LBM by ANCOVA (6536±630 v. 6282±641 kJ/d, P=0·2191), but remained significant when adjusted for BCM (6680±744 v. 6128±756 kJ/d, P=0·0249). Fat mass explained a significant amount of variation in RMR in women (r2 0·28, P=0·0038), but not in men (r2 0·03, P=0·3301). The relationships between body fat and the various subcompartments of BCM and RMR require further elucidation.

Effects of fat mass and body fat distribution on resting metabolic rate in the elderly

Metabolism ◽  
2001 ◽  
Vol 50 (8) ◽  
pp. 972-975 ◽  
Author(s):  
Petra M. L[uuml ]hrmann ◽  
Birgit M. Herbert ◽  
Monika Neuh[auml ]user-Berthold
Keyword(s):  
Metabolic Rate ◽  
Body Fat ◽  
Fat Mass ◽  
Resting Metabolic Rate ◽  
Fat Distribution ◽  
The Elderly ◽  
Body Fat Distribution

Resting Metabolic Rate in Adults with Facioscapulohumeral Muscular Dystrophy (FSHD)

2021 ◽  
Author(s):  
Kathryn A Vera ◽  
Mary McConville ◽  
Michael Kyba ◽  
Manda L. Keller-Ross
Keyword(s):  
Muscular Dystrophy ◽  
Metabolic Rate ◽  
Body Fat ◽  
Fat Mass ◽  
Lean Mass ◽  
Resting Metabolic Rate ◽  
Carbon Dioxide Production ◽  
Facioscapulohumeral Muscular Dystrophy ◽  
Whole Body ◽  
Body Fat Mass

Determine whether resting metabolic rate (RMR) is altered in adults with facioscapulohumeral muscular dystrophy (FSHD). Eleven people with FSHD (51±12yrs, 2 females) and eleven controls (48±14yrs, 2 females) completed one visit, including 30-minutes of indirect calorimetry and dual-energy x-ray absorptiometry (DXA) scanning. RMR was calculated from resting oxygen consumption/carbon dioxide production; regional/whole-body fat mass and lean mass were collected from the DXA scan. Absolute RMR was 15% lower in FSHD (p=0.04); when normalized to regional/local lean mass, no differences in RMR were observed (p>0.05). Absolute RMR was correlated with total lean mass for all participants combined (p<0.01, r=0.70, males only: p<0.01, r=0.81) and when analyzed separately (FSHD males: p=0.001, r=0.92 and control males: p=0.004, r=0.85). Whole-body lean mass was 16% lower in FSHD and leg, arm and appendicular lean mass were lower in FSHD (p<0.05 for all), though trunk lean mass was not (p=0.15). Whole-body fat mass was 45% higher in FSHD, with greater leg fat mass (p=0.01), but not trunk or arm fat mass (p>0.05 for both). When RMR was expressed relative to lean body mass, no differences in RMR were found, indicating that the lower levels of lean mass observed in FSHD patients likely contribute to the lower absolute RMR values. Novelty bullets: • Resting metabolic rate (RMR) is lower among people with FSHD, as compared with controls • The reduced RMR among people with FSHD is due to disease-related loss in muscle mass and likely related to lower physical activity and/or exercise levels.

The Influence of Age, Sex and Body Mass Index on the Effectiveness of Brisk Walking for Obesity Management in Adults: A Systematic Review and Meta-Analysis

2017 ◽  
Vol 14 (5) ◽  
pp. 389-407 ◽  
Author(s):  
Leon Mabire ◽  
Ramakrishnan Mani ◽  
Lizhou Liu ◽  
Hilda Mulligan ◽  
David Baxter
Keyword(s):  
Body Mass Index ◽  
Body Weight ◽  
Waist Circumference ◽  
Body Fat ◽  
Fat Mass ◽  
Fat Free Mass ◽  
Body Fat Percentage ◽  
Brisk Walking ◽  
Obesity Management ◽  
Fat Percentage

Background:Brisk walking is the most popular activity for obesity management for adults. We aimed to identify whether participant age, sex and body mass index (BMI) influenced the effectiveness of brisk walking.Methods:A search of 9 databases was conducted for randomized controlled trials (RCTs). Two investigators selected RCTs reporting on change in body weight, BMI, waist circumference, fat mass, fat-free mass, and body fat percentage following a brisk walking intervention in obese adults.Results:Of the 5072 studies screened, 22 met the eligibility criteria. The pooled mean differences were: weight loss, –2.13 kg; BMI, –0.96 kg/m2; waist circumference, –2.83 cm; fat mass, –2.59 kg; fat-free mass, 0.29 kg; and body fat percentage, –1.38%. Meta-regression of baseline BMI showed no effect on changes.Conclusions:Brisk walking can create a clinically significant reduction in body weight, BMI, waist circumference, and fat mass for obese men and women aged under 50 years. Obese women aged over 50 years can achieve modest losses, but gains in fat-free mass reduce overall change in body weight. Further research is required for men aged over 50 years and on the influence of BMI for all ages and sexes.

Resistive training increases fat-free mass and maintains RMR despite weight loss in postmenopausal women

1995 ◽  
Vol 79 (3) ◽  
pp. 818-823 ◽  
Author(s):  
A. S. Ryan ◽  
R. E. Pratley ◽  
D. Elahi ◽  
A. P. Goldberg
Keyword(s):  
Weight Loss ◽  
Body Weight ◽  
Postmenopausal Women ◽  
Body Fat ◽  
Fat Mass ◽  
Management Program ◽  
Fat Free Mass ◽  
Percent Body Fat ◽  
Plasma Norepinephrine ◽  
Resistive Training

Percent body fat increases with age and is often accompanied by a loss in muscle mass, strength, and energy expenditure. The effects of 16 wk of resistive training (RT) alone or with weight loss (RTWL) on strength (isokinetic dynamometer), body composition (dual-energy X-ray absorptiometry), resting metabolic rate (RMR) (indirect calorimetry), and sympathetic nervous system activity (catecholamines) were examined in 15 postmenopausal women (50–69 yr). RT resulted in significant improvements in upper and lower body strength in both groups (P < 0.01). The nonobese women in the RT group (n = 8) did not change their body weight or fat mass with training. In the obese RTWL group (n = 7), body weight, fat mass, and percent body fat were significantly decreased (P < 0.001). Fat-free mass and RMR significantly increased with training in both groups combined (P < 0.05). There were no significant changes in resting arterialized plasma norepinephrine or epinephrine levels in either group with training. RT increases strength with and without weight loss. Furthermore, RT and RTWL increase fat-free mass and RMR and decrease percent fat in postmenopausal women. Thus, RT may be a valuable component of an integrated weight management program in postmenopausal women.

Pharmacological characterization of a small molecule inhibitor of c-Jun kinase

2008 ◽  
Vol 295 (5) ◽  
pp. E1142-E1151 ◽  
Author(s):  
Helen Cho ◽  
Shawn C. Black ◽  
David Looper ◽  
Manli Shi ◽  
Dawn Kelly-Sullivan ◽  
...  
Keyword(s):  
Body Weight ◽  
Adipose Tissue ◽  
Body Fat ◽  
Small Molecule ◽  
Glycogen Synthase ◽  
High Fat ◽  
Pharmacological Characterization ◽  
Compound A ◽  
Weight Decrease

c-Jun NH2-terminal kinase (JNK) plays an important role in insulin resistance; however, identification of pharmacologically potent and selective small molecule JNK inhibitors has been limited. Compound A has a cell IC50 of 102 nM and is at least 100-fold selective against related kinases and 27-fold selective against glycogen synthase kinase-3β and cyclin-dependent kinase-2. In C57BL/6 mice, compound A reduced LPS-mediated increases in both plasma cytokine levels and phosphorylated c-Jun in adipose tissue. Treatment of mice fed a high-fat diet with compound A for 3 wk resulted in a 13.1 ± 1% decrease in body weight and a 9.3 ± 1.5% decrease in body fat, compared with a 6.6 ± 2.1% increase in body weight and a 6.7 ± 2.1% increase in body fat in vehicle-treated mice. Mice pair fed to those that received compound A exhibited a body weight decrease of 7 ± 1% and a decrease in body fat of 1.6 ± 1.3%, suggesting that reductions in food intake could not account solely for the reductions in adiposity observed. Compound A dosed at 30 mg/kg for 13 days in high-fat fed mice resulted in a significant decrease in phosphorylated c-Jun in adipose tissue accompanied by a decrease in weight and reductions in glucose and triglycerides and increases in insulin sensitivity to levels comparable with those in lean control mice. The ability of compound A to reduce the insulin-stimulated phosphorylation of insulin receptor substrate-1 (IRS-1) von Ser307 and partially reverse the free fatty acid inhibition of glucose uptake in 3T3L1 adipocytes, suggests that enhancement of insulin signaling in addition to weight loss may contribute to the effects of compound A on insulin sensitization in vivo. Pharmacological inhibition of JNK using compound A may therefore offer an effective therapy for type 2 diabetes mediated at least in part via weight reduction.

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