Chapter 10 Part A Flashcards
Energy equilibrium
energy intake = energy expenditure
Positive energy balance
(weight gain)
energy intake > energy expenditure
Negative energy balance
(use more & lose fat)
energy intake < energy expenditure
Current state of obesity
Increase in percentage of obese individuals over the last 20 years
Westernized diet patterns (high in fat & calories)
in 1990 - no state had obesity >15%
in 2010 - 49 states had obesity >22%
Energy intake
amount of heat it takes to raise 1g of water 1 degrees Celsius
estimated via nutrient databases
calories based on bomb calorimeter
Fat = ___ kcal/g
9
Carbs = ___ kcal/g
4
Protein = ___ kcal/g
4
Alcohol = ___ kcal/g
7
The 3 main purposes that the body uses energy:
1) Basal metabolism
2) Physical activity
3) Thermic effect of food (digestion, absorption, transportation)
Thermogenesis/ thermoregulation
(4th use of energy)
increases body temp through shivering or fidgeting
Basal Metabolic Rate (BMR)
Minimum amount of energy in a fasting state
~60-70% of energy expenditure - includes HR, RR, and ongoing organ activity
BMR is only an estimate - it can vary 20-30%
Factors that increase basal metabolism
muscle mass body surface gender body temp thyroid (basal metabolic regulator) hormone level stress stimulants (caffeine, tobacco) recent exercise
Factors that decrease basal metabolism
restricted calorie intake
aging after 30 yo (decreases 1-2% each decade r/t loss of lean body mass)
Physical activity
Increases energy expenditure beyond BM as much as 25-40%
Choices made - active or inactive
Thermic effect of food (TEF)
Energy body uses to digest, absorb, transport, store, and metabolize nutrients consumed in the diet
5-10% of energy intake (varies among individuals)
Influenced by food composition (whether it’s rich in protein, CHO, fat)
% of energy used in protein rich meals
20-30% (use the most energy out of macronutrients)
% of energy used in CHO rich meals
5-10%
% of energy used in fat rich meals
0-3% (use least energy out of macronutrients)
Adaptive thermogenesis (thermoregulation)
Process of heat production
In non-voluntary activity
Varies between individuals
Brown fat
(Thermogenesis/ thermoregulation)
Appearance from increased capillaries
Protein creates energy rather than ATP
Direct calorimetry
(measuring energy expenditure) put person in room for 24h, measure heat -continuous measurements of heat output -accurate -expensive and complex -rarely used
Indirect calorimetry
(measuring energy expenditure)
- collect expired air
- predictable relationship btwn O2 consumed and CO2 expired
- accurate
- most common method
Doubly Labeled Water Technique
(Indirect measurement of energy expenditure)
- stable isotopes of H used tracers
- analyze blood and urine samples over days and weeks
- requires only periodic sampling
- does not require special arrangements or equipment
What’s better, a lower BMR or higher BMR?
-A person w/ a lower BMR burns calories slower and is at higher risk for gaining weight than people w/ higher BMRs
Estimated Energy Requirements (EERs)
- based on weight, height, gender, age, and phys. activity level
- estimates only
Harris-Benedict equation
- used in clinical settings
- nonactive estimate of E requirements
- based on weight, height, gender, and age (filling in with other numbers in equation)
Weight-for-height tables
(Body weight and composition Dx methods)
- for men & women
- assumes you’re in 1” heels
Body Mass Index (BMI)
(Body weight and composition Dx methods)
- function of your weight and height comparison
- exception: extremely athletic people
- cannot give Dx (of obesity, underweight, overweight) from BMI alone
Obesity related health conditions
(table 10-2 in book)
T2DM, surgical risks, skin disorders, CVD, gallstones, bone & joint disorders, shorter stature, pregnancy risks, etc.
Underwater weighing
(method to measuring body fat)
- accurate ~ 2-3% margin of error
- fat is less dense than lean tissue
- expensive
- possibly traumatic
“BodPod”
(method to measuring body fat)
- accurate ~ 2-3% margin of error
- determines the body volume
- air displacement (displace air in a sealed chamber)
- requires specialized equipment
Caliper test
(methods to estimate body fat)
-tool that pinches skin on back of the right forearm
-inexpensive, common
~3-4% margin of error
Bioelectrical impedance
(methods to estimate body fat)
- low-energy current that measures the resistance of electrical flow (fat is resistant to electrical flow)
- more resistance = more body fat
DEXA (dual x-ray photon absorptometry)
(methods to estimate body fat)
- x-ray body scan determines body fat
- most accurate, but expensive and not widely available
Upper body fat distribution
Android (apple shape)
- increased heath risk
- related to CVD, HTN, & T2DM
- men waist > 40”
- women waist > 35”
Lower body fat distribution
Gynoid (pear shape)
-lower heath risks
Hunger
Physiological drive for food
Controlled by internal body mechanisms
Apetite
Psychological drive for food
Satiety
(satisfied)
- Brought about when either hunger drive or appetite drive is fulfilled
- Hypothalamus is the integration site, regulating food intake
- Involves endocrine and nervous systems as well as BG levels & hormone secretions
Satiety is effected by (theres a lot)
- knowledge food has been eaten
- histamine from chewing
- stomach & intestinal expansion
- low energy dense foods provide expansion more than lighter foods
- digestive hormones
- filled nutrient receptors in GI tract
- CHOs increase serotonin (calmness)
- protein - decreases ghrelin (stimulates eating)
- macronutrient levels in the blood
- endorphins (pain killers), cortisol & ghrelin (increase appetite)
- leptin (signals satiety when fat mass is increasing)
Bottom line w/ energy and weight control
Energy intake must balance energy output for weight control
