Energy Balance and Weight
Management: Finding Your
Equilibrium
BIOL 103, Chapter 8-1
Today’s Topics
• Energy In
• Energy Out
• Body Composition: Understanding Fatness
and Weight
• Overweight and Obesity
Energy Balance
• Energy Intake vs. Energy Output
Energy Balance
• Energy equilibrium
– Intake ___ output
– Maintain weight
• Positive energy balance
– Intake ___ Output
– ___________________
• Negative energy
balance
– Intake ___ Output
– ___________________
Internal Cues that Regulate Energy
Intake
Energy In – Regulation of Intake
(Problem Set #8, Q 1)
• Internal cues
1. _______: prompts
eating (e.g.
stomach growling)
2. ________: Signals
to stop eating
3. ________: Tells
when you are
ready to eat again
• External cue
– _______________:
psychological desire
to eat
• Influenced by the
eating environment
(e.g. if you are at a
buffet, you might want
to eat more)
Energy In
• Key concept: Food intake is regulated by
sensations of (1) hunger (a physiological drive to
eat), (2) satiation (feelings of satisfaction that
lead to ending a meal), and (3) satiety (continued
feelings of fullness that delay that start of the
next meal). (4) Appetite is the psychological urge
to eat and often as _______________________.
• Question:
– Are your internal cues regulated by physiological drive
or psychological drive?
– How about your external cues?
What stimulates our internal/external
cues?
• Control by committee
– What factors stimulates our cues?
1. Internal: ____________________________
– Examples: in our GI tract, central nervous system, general
circulation
2. External: ____________________________
– Examples: where we are eating, what we are eating, who we
are eating with
Internal Factors
1. ____________________________
– Sense of fullness as the ingested food stretches your
stomach/intestine
• Ex: sushi and water
2. Neurological and hormonal factors
– ______________________________: appetite stimulator
hormone in the brain
• Neuropeptide Y activity can be affected by signals from ghrelin and
leptin  affects daily feeding pattern
• __________: stomach hormone that ___________________________
– _______________________________
• _____________: a hormone produced by adipose cells that signals
brain to _____________________________________
– _______________________________
External Factors that affect your
Energy Intake
1. ___________________________
– Energy density (_______of food)
•
High energy dense food vs. low energy dense food
– Balance of energy sources (carbs, fat, proteins)
•
•
Eating proteins  increase satiety
Eating fiber help suppress appetite
– Form ___________________
2. _____________________
– __________, texture, color temperature,
presentation…
External Factors
3. __________________
–
–
Super-size culture, “McDonald’s value meals”
“never ending bowl of soup”
4. Environmental and social factors
–
Eat more in cold weather, eat less in hot weather
•
–
–
Why?
_________________: region in our brain that regulate hunger
and satiety, respiration, body temperature, water balance, and
other body functions.
More people in the group  longer meals  eat more by 30%
5. __________________
–
Eating to cope with stress, low self-esteem, boredom, low
energy levels
Energy In: Regulatory Factors
How do our bodies use
energy?
1.
3.
Maintain basic physiological
functions such as breathing and
blood circulation (Resting
energy expenditure or REE)
To process the food we eat
(thermic effect of food or TEF)
To power physical activity (PA)
•
REE + TEF + PA = ___________
2.
Energy Out: Fuel Uses
• Major components of Energy Expenditure:
1. Resting Energy Expenditure (REE): __________________
• ____________________________
– Examples: breathing, heart beating, respiration, muscle tone, body
temperature, etc.
• Affected by body size, composition, age, and gender
2. Physical Activity (PA): energy spent during leisure, work,
and exercise
• ____________________________
• Affected by body size, fitness level, and type of activity
3. Thermic Effect of Food (TEF)
• Energy to ________________________________
– Foods that actually burn calories (usually contain more water than sugar;
contain fiber): celery, grapefruit, watermelon, lettuce, hot chili peppers,
tomatoes, lemon, etc. (This is just FYI)
How to Calculate your TEE
• Estimating total energy expenditure:
– Resting energy expenditure (REE)
• Males: 1.0 kcal/kg/hr
• Females: 0.9 kcal/kg/hr
• ________________________________________________
– Physical activity
• Estimated by how much an individual with a certain amount
of body weight exercised in a given time
• Refer to Table 8.2
– Thermic effect of food
• 0.1 x (REE + physical activity)
Estimating Energy Expenditure
• Just as there are DRIs for nutrients, there are
also DRIs for energy, called _______________
_____________________________________
– Definition: energy intake predicted to maintain
energy balance in a healthy person of normal
weight
– Equations for males and females
• Factors for age, weight, height, and physical activity
– Predicts ________________________________
• See Table 8.4 for more details
Body Composition: Understanding
Fatness and Weight
• Body composition
– Is the relative amount of fat and lean muscle mass
– Muscle is ______________ than fat
• Assessing body weight
– _______________________________________
•
•
•
•
BMI ≤ __________= underweight
BMI ___________________= normal weight
BMI ___________________= overweight
BMI ___________= obese
– Q: Does BMI indicate how much fat you have?
Problem Set 8, Question 2
•
BMI = 704.5 x [weight (lb)/height (in2)]
• REE for women = (weight in kg) x 0.9 x 24
• REE for men = (weight in kg) x 1.0 x 24
• TEF = 0.1 x (energy from physical activity + REE)
• TEE = REE + energy from physical activity + TEF
How to measure body fatness?
• Can do this because fat and lean tissues have different densities
1. _____________: Dual Energy X-ray Absorptiometry
–
–
Pros: Measures bone, fat mass, lean body mass (protein and water)
Con: too expensive
2. ______________________________________
–
Q: If 2 people with the same weight but different levels of fat were weighed
in water, who would weigh less?
3. _____________ uses displacement of air to measure fat vs. fat-free mass
4. ______________________ uses calibers to pinch “fatty” tissues and add
them up
–
Better practice to measure for malnutrition than for obesity
5. ______________________ uses electrical charge to run through lean
mass and fat. Lean tissue has more water = better conductance.
–
Con: if subject is dehydrated  inaccurately high levels of fat are estimated
Overweight and Obesity
• Overweight/Obesity is a major public health
problem
– A global problem
• US: __________ of American adults are
overweight/obese
– Affects adults and youth
– Healthy People 2020 goal: _____________ the
proportion of adults, adolescents, and children
who are obese
Factors in Development of Obesity
1. Biological:
1. Genetic/heredity
2. Fat cell development: number and size of fat cells
help determine how easily a person gains or loses
fat.
•
•
•
Hypercellular obesity: obesity due to an _____________
______________________________
Hypertrophic obesity: obesity due to an increase in the
______________________________
Hyperplastic obesity: obesity due to an increase in
____________________________________________
3. Sex and Age
4. ___________________________
Factors in Development of Obesity
2. Social and environmental
1. _________________________ (ex: periods of overeating
in food insecure families, rural vs. city life)
2. __________________________: “human formed,
developed, or structural areas”
•
Ex: safer vs. more dangerous neighborhoods, work environment
(Google offices with fitness gyms and chefs)
3. _____________________ (ex: family/friend may choose
the restaurant, “pizza night” every Fridays)
3. Lifestyle and behavior
1. ___________________ (ex: lack of exercise)
2. ___________________(ex: restrained eaters, binge
eaters)
Overweight and Obesity
• Health risks of overweight and obesity
– Heart disease, stroke, diabetes, hypertension,
metabolic syndrome, cancer, gallbladder disease,
joint disease, and sleep apnea
• Weight cycling or “yo-yo dieting”: _________
_____________________________________
– Associated with negative effects on health risks,
body composition, body fat distribution, and
energy expenditure.
– Prone to future weight gain