Energy Flashcards
can be simply defined as the minimum amount of energy expended that is compatible with life.
Basal energy expenditure (BEE)
– 2/3 of daily energy expenditure of an average person
– essential metabolic process required by the body at rest
– Minimum amount of energy needed to carry out vital processes
- The minimum energy expended to keep a resting, awake body alive
Basal Metabolism
– Amount of energy required for basal metabolic processes per unit of body weight per unit of time (eg.Kcal/kg/hr)
Basal Metabolic Rate
– similar to basal metabolism
– measured under actual conditions
Resting Metabolism
- Capacity to do work
- Needed for involuntary and voluntary activities
Energy
amount of heat required to raise the temp of 1 kg H2O to 10C
Kcal
Amount of energy needed when 1 kg is moved a distance of 1 m
Joule (J)
Conversion: 1 Kcal =
4.184 J
• Age: BMR is highest at birth up to ___ years of age
2 years
• Nutritional Status: Prolonged calorie undernutrition can cause
20-30% decrease in BMR
Body composition: The higher the proportion of muscles to fat and bone, the higher
the BMR is
• Body Surface area: Tall person has higher BMR then a short person who has
the same weight
• Sex: The BMR of women is ___ to ___% lower than that of men of the same age, height, and weight
10-12%
3 hormones that can cause higher BMR
Thyroxine, adrenaline, and stress hormones
basal metabolism
Basal thermogenesis
Exercise-induced thermogenesis
physical activity
thermic effect of food (TEF) or specific dynamic action of food (SDA)
Diet-induced thermogenesis
energy of adaptation (very variable)
Adaptive thermogenesis
• Pregnancy: BMR increases by ___% during the second and third trimesters of pregnancy
20%
• Sleep: BMR is slightly ___ during sleep
reduced
• Body Temperature: a rise in 1 degree F increases BMR by __%; a rise in 1 degree C increases BMR by
__%
7%;
13%
voluntary movement of the muscles and the support system
Physical Activity
– Energy used to digest, absorb food nutrients
– Diet-induced thermogenesis
Thermic Effect of Food (TEF)
Nonvoluntary physical activity
◦Increases in the sympathetic nervous system activity
◦Triggered by overeating or cold environment
Adaptive thermogenesis
Energy lost as heat
Brown adipose tissue
◦Measures heat output from the body using an insulated chamber
◦Expensive and complex
Direct calorimetry
◦Measures the amount of oxygen a person uses
◦A relationship exists between the body’s use of energy and oxygen
◦(1 L O2= 4.85 kcal)
Indirect calorimetry
◦Consume water containing 2H and 18O
◦Measure isotopes in body fluids
Stable isotopes (Doubly labeled water)
State in which energy intake, in the form of food and/or alcohol, matches the energy expended, primarily through basal metabolism and physical activity
Energy Balance
◦Energy intake >energy expended
◦Results in weight gain
Positive energy balance
◦Energy intake >energy expended
◦Energy intake
Negative energy balance
What is Obesity?
An excess of body fat
STORAGE FAT
ADIPOSE TISSUE
lower body fat distribution
gynoid: pear shape
Upper body fat distribution
android: apple shape
◦Associated with more heart disease, HPN, Type II Diabetes
◦Abdominal fat is released right into the liver
◦Fat affects liver’s ability to clear insulin and lipoprotein
◦Encouraged by testosterone and excessive alcohol intake
◦Defined as waist measurement of >40” in men and >35” in women
Upper-body (android) obesity
◦Encouraged by estrogen and progesterone
◦After menopause, upper-body obesity appears
◦Less health risk than upper-body obesity
Lower-body (gynecoid) obesity
- As a measurement prior to and during weight loss
- Reduction in waist circumference, even without significant weight loss, may result in reduction in cardiovascular risks
Measurement of Waist Circumference
◦Use calipers to measure subcutaneous fat
◦Mathematical formula estimates body composition
Skinfold thickness
◦Low-energy current to the body that measures the resistance of electrical flow
Bioelectrical impedance analysis
Desirable amount of body fat for men
8 –24% for men
Desirable amount of body fat for women
21 –35% for women
◦Estimate body volume by measuring amount of air displaced when body is in a chamber
◦With body weight, can estimate body density
Air displacement (Bod Pod)
◦An X-ray body scan that allows for the determination of body fat, fat-free soft tissue, and bone
◦Also used for study of osteoporosis
Dual-energy X-ray absorptiometry
Methods on determining TEF:
a. Usual or Mixed Diet- 6-10% of Total energy
expenditure
b. High protein Diet- 15% of total energy expenditure
c. High Fat and Carbohydrate Diet- 5% of Total energy
expenditure
Respiratory Quotient
CHO
1.0
Respiratory Quotient
CHON
0.8
Respiratory Quotient
Fat
0.7
Respiratory Quotient
Mixed Diet
0.85
