Energy Balance

energy balance

the relationship between energy intake and energy expenditure

energy equilibrium

when calories consumed matches the amount of energy expended

positive energy balance

energy exceeds energy expenditure and results in weight gain

negative energy balance

energy intake is less than energy expenditure and weight loss occurs

energy intake

energy amount of energy in food or beverages can be estimated using nutrient databases or software

calorie values here are derived directly by using a bomb calorimeter

basal metabolism

physical activity

digestion, absorption, and processing of ingested nutrients (TEF)

3 main purposes the body uses energy

thermogenesis

minor form of energy output

energy expended during fidgeting or shivering

basal metabolism (BMR)

minimum amount of energy expended in fasting to keep a resting, awake body alive in a warm, quiet environment

accounts for about 60-70% of total energy expenditure

processes involved include beating of heart, respiration of lungs, and activity of other organs

beating of heart

respiration of lungs

activity of other organs

processes involved in basal metabolism

60-70%

basal metabolism accounts for ?-?% of total energy expenditure

resting metabolism (RMR)

if a person is not fasting or rested, ? is used

factors that increase basal metabolism

factors:

• greater muscle mass

• larger body surface

• male gender

• body temp

• higher than normal secretions of thyroid hormones

• nervous system activity

• growth stages

• caffeine and tobacco use

• recent exercise

factors that decrease basal metabolism

factors:

• lower than normal secretions of thyroid hormones

• restricted calorie intake

• less body surface area and muscle mass

• older than 30 years old

physical activity

increases energy expenditure above basal needs by 25-40%

being active or inactive determines much of total energy expenditure:

climb stairs rather than taking the elevator

walk rather rather than drive

standing in a bus rather than sitting

inactivity

the increased rate of obesity in North America is caused in part by our ?

thermic effect of food (TEF)

energy used to digest, absorb, transport, store, and metabolize

accounts for 5-10% of energy consumed

influenced by food composition and size of meal

20-30%

TEF for protein rich meals is ?

5-10%

TEF for carb rich meals is ?

0-3%

TEF for fat rich meals

higher

larger meals have ? TEF values

direct calorimetry

indirect calorimetry

ways the energy used by the body is measured

height

weight

physical activity

age

factors that can be used to estimate the amount of energy used

estimated energy requirements (EERs)

estimate energy needs based on height, weight, gender, age, and physical activity level

EER for men 19 and older

662 - (9.53 x age) + PA x ([15.91 x WT] + [539.6 x HT])

EER for women 19 and older

354 - (6.91 x age) + PA x ([9.36 x WT] + [726 x HT])

hunger and appetite

drive our desire to eat

hunger

physiological drive to find and eat food

controlled by internal mechanisms such as organs, hormones, hormone-like factors, nervous system

appetite

psychological drive to eat

effected by external factors such as social custom, time of day, mood, memories, sight

long-term satiety

promoted by:

body composition and amount of body fat

adipose tissue secretes leptin to reduce food intake, which decreases body fat in theory

body mass index (BMI)

weight-for-height standard

convenient

applies to both men and women

BMI

body weight (in lb) x 703 / height² (in inches)

<18.5

underweight BMI

18.5 to <25

healthy weight BMI

25 to <30

overweight BMI (health risks may be seen, not necessarily a marker of overfat)

>30

obese BMI

does not apply to children, teens, other adults, and pregnant and lactating women

where BMI does not apply to people

skinfold thickness

bioelectrical impedance

dual energy X-ray absorptiometry (DEXA)

ways to measure body fat content

skinfold thickness

calipers used to measure fat layer under skin

bioelectrical impedance

painless, low-energy electrical current sent through the body

greater electrical resistance equals more adipose tissue

more

in bioelectrical impedance, greater electrical resistance means ? adipose tissue

dual energy X-ray absorptiometry (DEXA)

most accurate method of body fat content

whole-body scan estimates:

body fat

fat-free soft tissue

bone minerals

body fat

fat-free soft tissue

bone minerals

whole-body scan estimates ?

cardiovascular disease

hypertension

type 2 diabetes

upper body (android) obesity is related to:

males (high blood testosterone)

diets with glycemic load

high levels of alcohol intake

smokers

upper body (android) obesity is seen in:

waist circumference

upper body (android) obesity is assessed by measuring ?

>40 inches in males

upper body (android) waist circumference in males

>35 inches in females

upper body (android) waist circumference in females

10%

children with no obese parents have a ? chance of becoming obese

40%

if child has 1 obese parent, risk of child becoming obese increases to ?

80%

if both parents are obese, risk of child being obese soars to ?

weight gain patterns

even when identical twins are raised apart, they show similar ?

genes

account for 40-70% of weight differences

body type

metabolic rate

factors that affect hunger and satiety

factors that are effected weight differences due to genes

thrifty metabolism

use energy more frugally, store fat more readily

can be inherited

set-point theory

genetically predetermined body weight or fat content that is closely regulated

hypothalamus

the genetically predetermined body weight or fat content that is closely regulated may be due to the job of the ? monitoring amount of body fat and keeping it constant over time

thyroid hormone

when energy intake is reduced, ? secretions fall, slowing metabolism

storing fat

when weight is lost, body becomes more efficient at ?

learned behaviors

body weight similarities among family members are more from ?

gene pools

have not changed much over the last 50 years, but obesity has drastically increased

nature and nuture

both are involved in body weight and composition

overweight/obesity treatment

required long-term lifestyle and even sound weight-loss program

overweight/obesity treatment

healthy, active lifestyles with lifelong dietary modifications should be emphasized