energy chapter 2 © 2004, 2002 elsevier inc. all rights reserved
TRANSCRIPT
EnergyEnergy
Chapter 2Chapter 2
© 2004, 2002 Elsevier Inc. All rights reserved.
© 2004, 2002 Elsevier Inc. All rights reserved.
EnergyEnergy
Capacity to do work
Derived from the sun—photosynthesis in plants
Humans consume plants and animal flesh, thus benefiting from energy sources
Capacity to do work
Derived from the sun—photosynthesis in plants
Humans consume plants and animal flesh, thus benefiting from energy sources
© 2004, 2002 Elsevier Inc. All rights reserved.
Energy ExpenditureEnergy Expenditure
Resting energy expenditure (REE)
Thermic effect of food (TEF)
Activity expenditure
Resting energy expenditure (REE)
Thermic effect of food (TEF)
Activity expenditure
© 2004, 2002 Elsevier Inc. All rights reserved.
Factors Affecting REEFactors Affecting REE
Body size
Body composition
Age
Sex
Hormonal status
Fever
Extreme environmental temperatures
Body size
Body composition
Age
Sex
Hormonal status
Fever
Extreme environmental temperatures
© 2004, 2002 Elsevier Inc. All rights reserved.
Energy ExpenditureEnergy Expenditure
Basal energy expenditure (BEE)
Minimal energy compatible with life
Energy used over 24 hours
60% to 70% of total energy expenditure (TEE)
Basal energy expenditure (BEE)
Minimal energy compatible with life
Energy used over 24 hours
60% to 70% of total energy expenditure (TEE)
© 2004, 2002 Elsevier Inc. All rights reserved.
Energy Expenditure of Organs in Human AdultsEnergy Expenditure of Organs in Human Adults
© 2004, 2002 Elsevier Inc. All rights reserved.
Dual-Energy X-Ray AbsorptiometryDual-Energy X-Ray Absorptiometry
Courtesy The Dunn Nutrition Centre, University of Cambridge, Cambridge, England.
© 2004, 2002 Elsevier Inc. All rights reserved.
The Effect of Adding Spices to a Meal on the Resting Metabolic Rate (RMR) of Healthy SubjectsThe Effect of Adding Spices to a Meal on the Resting Metabolic Rate (RMR) of Healthy Subjects
(From McCrory P. et al. Energy balance, food intake and obesity. In: Hills AP, Wahlqvist ML [eds.]. Exercise and Obesity. London: Smith-Gordon and Co., Ltd., 1994.)
© 2004, 2002 Elsevier Inc. All rights reserved.
Estimating Energy RequirementsEstimating Energy Requirements
Each method for calculating energy needs differs and has limitations, so remember that they are only estimates of energy requirements.
Each method for calculating energy needs differs and has limitations, so remember that they are only estimates of energy requirements.
© 2004, 2002 Elsevier Inc. All rights reserved.
Units of Energy MeasurementUnits of Energy Measurement
Kilocalorie (kcal)
—Carbohydrate = 4 kcal/g
—Protein = 4 kcal/g
—Fat = 9 kcal/g
Kilojoule (kJ)—non–US countries; the metric value
—Carbohydrate = 17 kJ
—Protein = 17kJ
—Fat = 38 kJ
Kilocalorie (kcal)
—Carbohydrate = 4 kcal/g
—Protein = 4 kcal/g
—Fat = 9 kcal/g
Kilojoule (kJ)—non–US countries; the metric value
—Carbohydrate = 17 kJ
—Protein = 17kJ
—Fat = 38 kJ
© 2004, 2002 Elsevier Inc. All rights reserved.
Measuring Energy ExpenditureMeasuring Energy Expenditure
Direct calorimetry
Indirect calorimetry
Doubly labeled water
Direct calorimetry
Indirect calorimetry
Doubly labeled water
© 2004, 2002 Elsevier Inc. All rights reserved.
Factors for Physical Activity Levels (PAL) Based on Doubly Labeled Water (DLW) StudiesFactors for Physical Activity Levels (PAL) Based on Doubly Labeled Water (DLW) Studies
(Adapted from Shetty PS, et al. Energy requirements of adults: An update on basal metabolic rates (BMRs) and physical activity levels (PALs). Eur J Clin Nutr 50 (suppl 1): S11, 1996.)
© 2004, 2002 Elsevier Inc. All rights reserved.
Energy Value of FoodEnergy Value of Food