HBNS200: Energy Balance, Weight Control, and Eating Disorders

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 intake exceeds energy expenditure and results in weight gain

Negative energy balance

energy intake is less than energy expenditure and weight loss occurs

Positive energy balance is desired during growth stages such as?

Pregnancy, infancy, childhood, and adolescence

Does aging cause weight gain?

no it does not cause weight gain

Negative energy balance is desired in adults when?

body fatness exceeds healthy levels

Energy intake

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

Calorie values are dervied directly by using a?

bomb calorimeter

How can calroie content also be calculated?

by determining the grams of the energy-providing macronutrients and alcohol

The body used energy for what 3 main purposes?

basal metabolism, physical activity, and digestion, absorption, and processing of ingested nutrients

A minor form of energy out is called?

thermogenesis; energy expended during fidgeting or shivering

Basal metabolism

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

Basal metabolism account for about ___ to ____ of total energy expenditure

60 to 70%

What are the processes included in basal metabolism?

beating of heart, respiration of lungs, and activity of other organs

What are some factors that increase basal metabolism?

greater muscle mass, larger body surface, being male, body temp, higher than normal secretions of thyroid hormones, nervous system activity, growth stages, caffeine/tobacco use, and recent exercise

What are some factors that decrease basal metabolism?

lower than normal secretions of thyroid hormones, restricted calorie intake, less body surface area/muscle mass, and aging after age 30 years

Physical activity increases?

energy expenditure

Being ___ or ___ determines much of our total energy expenditure

active; inactive

The increased rate of ___ in North America is caused in part by our inactivity

obesity

Thermic effect of food

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

Thermic effect of food accounts for about ___ of energy consumed

10%

Thermogenesis

process of heat production; small contribution to total energy expenditure

When is thermogenesis produced?

when body expends energy for non-voluntary physical activity; fidgeting, shivering, maintaining muscle tone, and holding body upright

Basal Metabolic Rate percentage?

60%

Thermic effect of food percentage

10%

Physical activity percentage

30%

Energy used by the body can be measured by

direct and indirect calorimetry

Energy used can be estimated based on

height, weight, physical activity, and age

Direct calorimetry

estimates energy expenditure by measuring amount of heat released by the body; about 60% of energy the body uses leaves as heat

How is heat release measured?

by placing person in insulated chamber surrounded by layer of water; change in temperature determines amount of energy person expended

Indirect calorimetry

involves collecting expired air; predictable relationship between body’s use of energy and amount of oxygen consumed and carbon dioxide produced

Estimated Energy Expenditure (EERs)

measurements that can estimate energy needs

Hunger

physiological drive to find and eat food

What is hunger controlled by?

internal mechanisms such as organs, hormones, hormone-like factors, and nervou system

Appetite

psychological drive to eat

Appetite is affected by?

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

Although internal and external signals operate ____ to lead us to decide whether to reject or eat food, we can ____ these signals

simultaneously; override

Satiety

feeling satisfied and no longer have the drive to eat

What is the site of regulation?

Hypothalamus

Hypothalamus

communicates with endocrine and nervous system

The hypothalamus integrates?

internal cues of blood glucose levels, hormone secretions, and sympathetic nervous system

If the internal signals stimulate the satiety center what happens?

we stop eating

If the internal signals stimulate feeding centers what happens?

we eat more

Satiety is elicited by

sensory aspects of food, knowledge that food has been eaten, chewing, expansion of stomach and intestines, and effects of digestion/absorption/metabolism

Which hormone shuts off hunger during digestion?

cholecystokinin

The decrease of hormone ___ promotes short-term satiety

ghrelin

Long-term satiety is promoted by?

body composition and the amount of body fat

Adipose tissue secretes ___ to reduce food intake, which decreases body fat

leptin

Several hours after eating what happens?

concentrations of macronutrients fall and the body starts to use energy from stores

Which endorphins/hormones stimulate appetite and increase food intake?

cortisol and ghrelin

Ghrelin

produced in the stomach; stimulates hunger

Leptin

produced by adipose tissue; suppresses hunger

To estimate body weight and composition, it is recommended to evaluate?

total body fat, location of body fat, and weight-related medical problems

Body Mass Index

weight-for-heigh standard; applies to body men and women

Body Mass index is an indirect measure of?

body composition and an indication of health risk

Underweight

< 18.5 kg/m²

Normal weight

18.5-24.9 kg/m²

Overweight

25-29.9 kg/m²

Obese

> 30 kg/m²

What are the BMI limitations?

cannot distinguish between excess fat and muscle and bone mass

What is the desirable amount of body fat for men?

8% to 24%; over 24% considered obese

What is the desirable amount of body fat for women?

21% to 35%; over 35% considered obese

To measure body fat content what must be measured?

both body weight and body volume

Underwater weighing

body weight is measured under water and in air

Air Displacement

BodPod; the space a person takes up in a chamber is measured

Skinfold thickness

calipers used to measure fat layer under skin

Bioelectrical imepdance

painless, low-energy electrical current sent through body; based on the principle that body fat resists the flow of electricity because it is low in water/electrolytes

Dual energy X-ray Absorptiometry (DXA)

measures body fat by releasing small doses of radiation through the body to assess body fat and bone density

DXA whole-body san estimates

body fat, fat-free soft tissue, and bone minerals

Waist circumference

estimator of abdominal obesity

Waist circumference determines the presence of?

abdominal obesity and increased risk

Waist circumference for women

> 35 inches (88 cm) increased risk

Waist circumference for men

> 40 inches (102 cm) increased risk

Visceral (abdominal) fat

an independent health risk that can cause cardiovascular disease, type 2 diabetes, insulin resistance, and premature all-cause mortality

Children with no obese parents have ___ chance of becoming obese

10%

If child has 1 obese parent, risk increases to?

40%

If both parents are obese, risk soars to?

80%

Genes account for ___ to ___ of weight differences

40 to 70%

Set-point theory

genetically predetermined body weight for fat content that is close regulated

When energy intake is reduced?

thyroid hormone secretions fall, slowing metabolism

When weight is lost, body becomes more?

efficient at storing fat

Environmental factors define

when eating is appropriate, what is preferable to eat, and how much is eaten

Even with a genetic predisposition for leanness…

it is possible to gain excess fat

Even with a genetic predisposition to obesity…

it can be avoided with a healthy diet and regular physical activity

Sound weight-loss programs should include

control of energy intake, regular physical activity, and control of problem behaviors

Weight-loss program is considered successful when

those involved remain at or close to lower eights

Only about ___ of people following commercial diet programs succeed

5%

Typically, __ of weight loss is regained within 3 to 5 years

1/3

What is currently the only approach to show weight loss success

surgical approaches

Adipose tissue contains

3500 kcal/b

To lose 1 pound per week, energy intake must be

decreased by 500 kcal/day

Women may need to limit intake to

1200 kcal/day

Men may limit to

1500 kcal/day

Chain-breaking

separate behaviors that occur together

Stimulus control

after the environment to minimize stimuli for eating

Cognitive restructuring

change frame of mind regarding eating

Contingency management

prepare for situations that may trigger overeating

Self-monitoring

track food eaten, when, why, how you feel, physical activities, body weight

Eat a low-fat, high carbohydrate diet

25% fat intake; 56% carbohydrate intake from fruits, vegetables, and grains