Chapter 6: Energy Balance Flashcards
defined as the capacity to do work
energy
primary energy source of all living organism is from sun, through the process of _____
it allows green plants to synthesize glucose where other nutritive biomolecules such as proteins, fats, and complex carbohydrates are derived
photosynthesis
humans obtain nutrients by consuming foods
in the body, the energy is made available by oxidation of nutrients from food
the stored energy potential of consumed food is referred as
energy intake (energy in)
the energy from food is converted to various forms and is utilized in the body to support daily functions (voluntary and involuntary)
the set of used energy is called? which determines weight gain, loss, or maintenance
energy expenditure (energy out)
each individual requires a certain level of dietary energy intake called? to meet his/her nutritional needs necessary to support growth and development
this requirement include: sex, age, height, weight, level os physical activity
energy requirement
energy - measurement
measurement of heat or energy produced by food in the body
calorimetry
gold standard to measure energy expenditure to optimize the energy prescription
indirect calorimetry
energy - measurement
standard unit of measuring heat is in terms of _____
defined as amount of energy required to raise the temp of 1 ml of water at 15c by 1c
calorie
energy - measurement
since amounts are too high, _____ is often used which is equivalent to 1000 kcal
kilocalorie
energy - measurement
in the metric system _____ is used as the measure of energy in terms of mechanical work with the equivalence of 4.184 per calorie
joule
conversion of joule to kcal
4.138
calorimetry - methods
makes use of a bomb calorimeter or a respiration chamber as instruments to measure heat production directly
direct calorimetry
calorimetry - methods (direct)
a well-insulated container used to measure the heat produced by a known amount of food when it is burned
bomb calorimeter
calorimetry - methods (direct)
*bomb calorimeter
the amount of heat released by the burning of food is called?
heat of combustion or gross energy value of food
calorimetry - methods (direct)
*bomb calorimeter
provides an estimate of the potential of food, it overstates the amount of energy derived from the food by the body
reason: the human body is not as efficient as the bomb calorimeter in releasing all the potential energy of food since it cannot metabolize all of the energy-yielding nutrients (macros)
-
calorimetry - methods (direct)
*bomb calorimetry
to correct discrepancies, the _____ (number of kcal that the body derives from food) are used
4 kcal cho
4 kcal chon
9 kcal fat
atwater’s physiologic fuel values
calorimetry - methods (direct)
refers to a small well-insulated room that operates on the same principle as the bomb calorimeter
ex: heat is directly measured and used to measure energy expenditure in humans. the heat given off by the subject in the chamber is directly proportional to the energy expended but it does not provide information on the kind of fuel being oxidized
respiration chamber
calorimetry - methods (indirect)
gold standard method
more common method of measuring energy expenditure in humans, measure oxygen consumption and carbon dioxide production to estimate expenditure
indirect calorimetry
calorimetry - methods (indirect)
is an important concept when measuring oxygen consumption and carbon dioxide production
is the ratio between the expired carbon dioxide and inspired oxygen
respiratory quotient (rq)
calorimetry - methods (indirect)
RQ formula
RQ = volume of co2 expired/volume of o2 inspired
calorimetry - methods (indirect)
useful in determining the type of fuel being metabolized
under normal conditions and usual diet, when both cho and fat are being use for energy, RQ is usually _____
0.82
calorimetry - methods (indirect)
RQ of energy-yielding nutrients if used as sole energy source (cho)
1.0
calorimetry - methods (indirect)
RQ of energy-yielding nutrients if used as sole energy source (fat)
0.7
calorimetry - methods (indirect)
RQ of energy-yielding nutrients if used as sole energy source (chon)
0.8
calorimetry - methods (indirect)
RQ of energy-yielding nutrients if used as sole energy source (mixed diet)
0.85
calorimetry - methods (indirect)
the source of oxygen is known like in the case of the Benedict Roth Respiration Apparatus for measuring energy expenditure at rest
closed circuit
calorimetry - methods (indirect)
the source of oxygen is outside air-like in the case of Kofranyi-Michaelis Respirometer, suitable for measuring energy during activity
measures inhaled air
open circuit
calorimetry - methods (indirect)
heart rate monitoring method
-
calorimetry - methods (indirect)
considered as the gold standard in measuring energy requirements and energy balance in humans
based on the principle that c02 production can be estimated from the different in the elimination rates of body hydrogen and oygen
doubly labeled water (DLW) technique
calorimetry - methods (indirect)
measures hydrogen atoms of the body water through water losses and oxygen atoms of the body as c02 gas
use stable isotopes of water label with deuterium oxide
doubly labeled water (DLW) technique
energy balance equation
when energy intake = energy expenditure, the individual is said to be in state of _____
energy balance
energy balance equation
in energy balance, its results in _____ and maintenance of body composition that normally is about 15% and 25% body fat for males and females, respectively
weight maintenance
energy balance equation
when energy intake > energy expenditure, the individual is in _____
this indicated tissue synthesis (anabolism) and is seen in growing children and pregnant women and adult males and femailes gaining weight; excess energy is stores as adipose tissue (body fat)
positive energy balance
energy balance equation
when energy intake < expenditure, individual is in _____
means that the body tissues, particularly body fat, are broken down (catabolism) to provide the needed energy
results in growth failure in children and weight loss in adults
negative energy balance
energy intake
refers to the maximum amount of energy that can be derived in direct calorimetry because of the incomplete utilization of food in the body
metabolizable fuel value
energy intake
considers the average digestibility (coefficient of digestibility) of cho, chon, and fats in a mixed diet
cho 98%
chon 93%
fat 95%
physiologic fuel value (pfv)
energy intake - factors that affect food intake
refers to the irritating feeling that motivated a person to eat
painful sensation caused by a lack of food that initiates food-seeking behavior
hunger
energy intake - factors that affect food intake
physiologic desire to eat
an integrated response to the sight, smell, thought, or taste of food that initiated or delays eating
appetite
energy intake - factors that affect food intake
stops one from eating
suppresses hunger and determines how much time passes between meals
satiety
energy intake - factors that affect food intake
maintains the signal not to start eating again
determines how much food is consumed during a meal
satiation
energy intake - factors that control food intake
responsible for feeding and satiety centers that control food intake
hypothalamus
energy intake - factors that control food intake
refers to a chemical produced in the brain that stimulates appetite, diminishes energy expenditure, and increases fat storage
neuropeptide y
energy intake - factors that control food intake
refers to the hormone encoded by the ob gene in the adipose tissues that diminishes appetite and increases energy expenditure
leptin
energy expenditure
comprises about 2/3 of the daily energy expenditure of an average person
basal metabolism
energy expenditure
essential metabolic process required by the body at rest
also defined as the minimum amount of energy required to carry out vital processes
basal metabolism
energy expenditure - basal metabolism
is amount of energy require for basal metabolic processes per unit of body weight per unit time
ex: kcal/kg/hour
basal metabolic rate
energy expenditure - basal metabolism
similar to basal metabolism, however, it is measured under actual (not standardized) conditions, and subjects who do not have to be in post-absorptive state include TEF
resting metabolism
energy expenditure - basal metabolism
amount of energy required for the basal metabolic processes and TEF per unit weight per unit time; also called resting energy expenditure
resting metabolic rate
factors affecting BMR
muscles, brain, liver, and various glands and organs are relatively more active metabolically
the higher the proportion of muscles to fat and bone, the higher the BMR is
body composition
factors affecting BMR
a tall, lean person has a greater _____ than a short stocky person of the same weight
body surface area
factors affecting BMR
sex: _____ have higher proportion of muscle to fat than females
males
factors affecting BMR
the BMR of women is 10-12% lower than males of the same age, height, and weight
10-12%
factors affecting BMR
BMR changes with _____ because of changes in physiologic processes as well as metabolic activity
age
factors affecting BMR
*age
BMR is highest at _____ up to _____ years old, gradually declines throughout life except for a short-term rise during puberty
birth - 2 y/o
factors affecting BMR
hormones secreted by the adrenal and thyroid glands have a significant effect on basal energy needs
endocrine secretion
factors affecting BMR
hormones that cause increase in BMR
thyroxine, adrenaline, and stress hormones
factors affecting BMR
prolonged calorie undernutrition can cause a 20-30% decrease in bmr
habitual high-energy intake can increase bmr
nutritional status
factors affecting BMR
prolonged calorie undernutrition
privo conservation
factors affecting BMR
prolonged decrease consumption
luxus consumption
factors affecting BMR
BMR increases by 20% during the _____ trimesters of pregnancy due to increased metabolic rate of the fetus, placenta, and other maternal tissues
2nd and 3rd trimesters
factors affecting BMR
a decrease in environmental temp (ET) can cause shivering and thus increase production of _____
an increase in ET causes sweating, producing a cooling effect
cold-induced thermogenesis
factors affecting BMR
slightly reduced during sleep
bmr
factors affecting BMR
refers to the voluntary movement of the muscles and the support system
physical activity
pertains to energy cost of the physical activity
thermic effect of exercise
- number and type of muscles involved
- intensity and duration of the activity
-physical activities can be classified as sedentary, moderately active, or very active
factors affecting TEE
estimates energy requirements of processing of food
refers to direct or indirect calorimetry
thermic effect of food (TEF)
other effect of thermic effect of food (TEF)
Diet-Induced Thermogenesis (DIT)
methods - determining TEF
6-10% of total energy expenditure for basal and physical activity
on usual mixed diet
methods - determining TEF
15% of total energy expenditure for basal and physical activity
high protein diet
methods - determining TEF
5% total of energy expenditure for basal and physical activity
high fat and carbohydrate diet
