Energy Balance and Weight Management: Finding Your

EquilibriumBIOL 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 Factors1. ____________________________

– 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 Factors3. __________________

– 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. Maintain basic physiological

functions such as breathing and blood circulation (Resting energy expenditure or REE)

2. To process the food we eat (thermic effect of food or TEF)

3. To power physical activity (PA)

• REE + TEF + PA = ___________

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 gender2. 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 densities1. _____________: 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 mass4. ______________________ 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/heredity2. 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 Age4. ___________________________

Factors in Development of Obesity2. 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 behavior1. ___________________ (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