scholarly journals Carbs versus fat: does it really matter for maintaining lost weight?

2018 ◽  
Author(s):  
Kevin D Hall ◽  
Juen Guo
Keyword(s):  
Energy Expenditure ◽  
Energy Conservation ◽  
Diet Composition ◽  
Co2 Production ◽  
Dietary Carbohydrates ◽  
Production Rates ◽  
Diet Adherence ◽  
Daily Average ◽  
Metabolic Advantage

The most read article of 2018 published in The BMJ (https://doi.org/10.1136/bmj.k4583) claimed that restricting dietary carbohydrates offers a metabolic advantage to burn more calories and thereby help patients maintain lost weight. However, analyzing the data according to the original pre-registered statistical plan resulted in no statistically significant effects of diet composition on energy expenditure. The large reported diet effects on energy expenditure calculated using the revised analysis plan depended on data from subjects with excessive amounts of unaccounted energy. Adjusting the data to be commensurate with energy conservation resulted in a diet effect that was less than half the value reported in The BMJ paper. Furthermore, the measured daily average CO2 production rates were not significantly different between the diets and the reported expenditure differences were due to inaccurate calculations based on false assumptions about diet adherence.

Longitudinal Measurements of Resting Energy Expenditure by Indirect Calorimetry in Healthy Term Infants during the First 2 Months of Life

2018 ◽  
Vol 36 (09) ◽  
pp. 918-923
Author(s):  
Sourabh Verma ◽  
Sean M. Bailey ◽  
Pradeep V. Mally ◽  
Heather B. Howell
Keyword(s):  
Pilot Study ◽  
Energy Expenditure ◽  
Indirect Calorimetry ◽  
Resting Energy Expenditure ◽  
Co2 Production ◽  
Term Infants ◽  
Longitudinal Measurements ◽  
Expired Gas ◽  
Carbon Dioxide Co2 ◽  
Resting Energy

Objective To determine longitudinal measurements of resting energy expenditure (REE) by indirect calorimetry (IC) in healthy term infants during the first 2 months of life. Study Design An outpatient prospective pilot study was performed in healthy term infants to estimate REE by measuring expired gas fractions of oxygen (O2) and carbon dioxide (CO2) with IC in a respiratory and metabolic steady state. Results A total of 30 measurements were performed. Fourteen subjects completed measurements at both 1 and 2 months of life, and two subjects had only measurements made at 1 month of life. Mean REE values were 64.1 ± 12.7 and 58.4 ± 14.3 kcal/kg/d at 1 and 2 months of age, respectively. Mean O2 consumption and CO2 production measurements were 9.3 ± 2.0 and 7.7 ± 1.2 mL/kg/min and 8.1 ± 2.2 and 6.4 ± 1.1 mL/kg/min at 1 and 2 months of age, respectively. Conclusion This pilot study demonstrates longitudinal measurements of REE by IC in healthy term infants during the first 2 months of life. We also demonstrate that, overall, there is consistency in REE values in this population, with a likely decrease in individual longitudinal measurements over the first 2 months of life.

scholarly journals Energy expenditure of free-living reindeer estimated by the doubly labelled water method

Rangifer ◽  
2000 ◽  
Vol 20 (2-3) ◽  
pp. 211 ◽  
Author(s):  
Geir Gotaas ◽  
Eric Milne ◽  
Paul Haggarty ◽  
Nicholas J.C. Tyler
Keyword(s):  
Energy Expenditure ◽  
Rangifer Tarandus ◽  
Water Flux ◽  
Co2 Production ◽  
Wild Ungulates ◽  
Free Living ◽  
Doubly Labelled Water ◽  
Svalbard Reindeer ◽  
Mountain Pasture ◽  
The Mean

The doubly labelled water (DLW) method was used to measure total energy expenditure (TEE) in three male reindeer (Rangifer tarandus tarandus) aged 22 months in winter (February) while the animals were living unrestricted at natural mountain pasture in northern Norway (69°20'N). The concentrations of 2H and l8O were measured in water extracted from samples of faeces collecred from the animals 0.4 and 11.2 days after injection of the isotopes. Calculated rates of water flux and CO2-production were adjusted to compensate for estimated losses of 2H in faecal solids and in methane produced by microbial fermentation of forage in the rumen. The mean specific TEE in the three animals was 3.057 W.kg-1 (range 2.436 - 3.728 W.kg1). This value is 64% higher than TEE measured by the DLW method in four captive, non-pregnant adult female reindeer in winter and probably mainly reflects higher levels of locomotor activity in the free-living animals. Previous estimates of TEE in free-living Rangifer in winter based on factorial models range from 3.038 W.kg-1 in female woodland caribou (R. t. caribou) to 1.813 W.kg-1 in female Svalbard reindeer (R. t. platyrhynchus). Thus, it seems that existing factorial models are unlikely to overestimate TEE in reindeer/caribou: they may, instead, be unduly conservative. While the present study serves as a general validation of the factorial approach, we suggest that the route to progress in the understanding of field energetics in wild ungulates is via application of the DLW method.

scholarly journals Effect of diet composition on energy expenditure during weight loss: the POUNDS LOST Study

2011 ◽  
Vol 36 (3) ◽  
pp. 448-455 ◽  
Author(s):  
G A Bray ◽  
S R Smith ◽  
L DeJonge ◽  
R de Souza ◽  
J Rood ◽  
...  
Keyword(s):  
Weight Loss ◽  
Energy Expenditure ◽  
Diet Composition

Energy-intake restriction and diet-composition effects on energy expenditure in men

1991 ◽  
Vol 53 (2) ◽  
pp. 430-436 ◽  
Author(s):  
W V Rumpler ◽  
J L Seale ◽  
C W Miles ◽  
C E Bodwell
Keyword(s):  
Energy Expenditure ◽  
Energy Intake ◽  
Diet Composition ◽  
Composition Effects

Determining energy expenditure in preterm infants: comparison of 2H(2)18O method and indirect calorimetry

1992 ◽  
Vol 263 (3) ◽  
pp. R685-R692 ◽  
Author(s):  
C. L. Jensen ◽  
N. F. Butte ◽  
W. W. Wong ◽  
J. K. Moon
Keyword(s):  
Heart Rate ◽  
Energy Expenditure ◽  
Preterm Infants ◽  
Indirect Calorimetry ◽  
Water Flux ◽  
High Ratio ◽  
Individual Variability ◽  
Study Time ◽  
Co2 Production ◽  
Turnover Rates

The doubly labeled water (2H(2)18O) method used to estimate total energy expenditure (EETotal) is particularly sensitive to analytic error in preterm infants, because of their high percentage of body water and the high ratio of water flux to CO2 production. To evaluate further use of this method, the EE of 12 preterm infants was measured by indirect calorimetry and 2H(2)18O simultaneously and continuously for 5 days. Initial infant weight, age, and postconceptional age were (means +/- SD) 1,674 +/- 173 g, 4.4 +/- 2.6 wk, and 34.6 +/- 1.6 wk, respectively. The indirect calorimeter system included an air-temperature-controlled chamber and heart rate monitor. EE was measured by indirect calorimetry for 85.6 +/- 4.7% of study time and estimated from the linear regression of heart rate on EE for 14.4 +/- 4.7% of study time. The 2H(2)18O method entailed an initial dose of 100 mg 2H2O and 250 mg 18O/kg and a final dose of 75 mg 18O/kg; urine was collected twice daily. 2H and 18O enrichments were measured by gas-isotope-ratio mass spectrometry. EE was calculated from measured 2H and 18O dilution spaces (NH, NO), turnover rates (kH, kO), and measured respiratory quotient. The ratio of 2H to 18O dilution spaces was 1.01 +/- 0.01 and the ratio of kO to kH was 1.16 +/- 0.04. Estimation of EE from 2H(2)18O and indirect calorimetry agreed within 1%, although individual variability in methods was large.

Combined heart rate and activity improve estimates of oxygen consumption and carbon dioxide production rates

1996 ◽  
Vol 81 (4) ◽  
pp. 1754-1761 ◽  
Author(s):  
Jon K. Moon ◽  
Nancy F. Butte
Keyword(s):  
Carbon Dioxide ◽  
Heart Rate ◽  
Oxygen Consumption ◽  
Energy Expenditure ◽  
Carbon Dioxide Production ◽  
Alternative Methods ◽  
Prediction Errors ◽  
Nonlinear Functions ◽  
Production Rates ◽  
Basal Energy Expenditure

Moon, Jon K., and Nancy F. Butte. Combined heart rate and activity improve estimates of oxygen consumption and carbon dioxide production rates. J. Appl. Physiol.81(4): 1754–1761, 1996.—Oxygen consumption (V˙o 2) and carbon dioxide production (V˙co 2) rates were measured by electronically recording heart rate (HR) and physical activity (PA). Mean daily V˙o 2 andV˙co 2 measurements by HR and PA were validated in adults ( n = 10 women and 10 men) with room calorimeters. Thirteen linear and nonlinear functions of HR alone and HR combined with PA were tested as models of 24-h V˙o 2 andV˙co 2. Mean sleepV˙o 2 andV˙co 2 were similar to basal metabolic rates and were accurately estimated from HR alone [respective mean errors were −0.2 ± 0.8 (SD) and −0.4 ± 0.6%]. The range of prediction errors for 24-h V˙o 2 andV˙co 2 was smallest for a model that used PA to assign HR for each minute to separate active and inactive curves (V˙o 2, −3.3 ± 3.5%; V˙co 2, −4.6 ± 3%). There were no significant correlations betweenV˙o 2 orV˙co 2 errors and subject age, weight, fat mass, ratio of daily to basal energy expenditure rate, or fitness. V˙o 2,V˙co 2, and energy expenditure recorded for 3 free-living days were 5.6 ± 0.9 ml ⋅ min−1 ⋅ kg−1, 4.7 ± 0.8 ml ⋅ min−1 ⋅ kg−1, and 7.8 ± 1.6 kJ/min, respectively. Combined HR and PA measured 24-h V˙o 2 andV˙co 2 with a precision similar to alternative methods.

RATE OF CO2 PRODUCTION (RaCO2) AND ESTIMATES OF ENERGY EXPENDITURE (EE) IN WRESTLING PRACTICE 271

1997 ◽  
Vol 29 (Supplement) ◽  
pp. 47 ◽  
Author(s):  
C. A. Horswill ◽  
D. G. Curby ◽  
W. P. Bartoli ◽  
R. Murray
Keyword(s):  
Energy Expenditure ◽  
Co2 Production
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