Energy Balance

Question 1

What are the major components of “energy in” vs. “energy out.”

Answer 1

Energy intake - calories (carbs, proteins, fats, alcohol)
Energy expended - basal metabolism, TEF (thermic effect of food -> absorbing nutrients), physical activity, thermogenesis

Question 2

What is thermogenesis?

Answer 2

the generation of heat; used in physiology and nutrition studies as an index of how much energy the body is expending.

Question 3

What are the relative contributions of the 3 major components of energy expenditure (basal metabolism, physical activity, thermic effect of food)? Identify the most variable of these components.

Answer 3

Basal metabolism -> maintains life when body is in rest
TEF -> energy required to process food
Physical activity -> voluntary movement of muscles, support systems (most variable)

Question 4

List several factors that can affect BMR.

Answer 4

• gender
• growth
• age
• physical activity
• body comp/size

Question 5

What is a BMI? What is the equation?

Answer 5

a measure of a person’s weight relative to height (divide weight (kg) by the square of the height (m) ( imperial system: weight in pounds divide by square of height in inches times 703)

Question 6

How is BMI used to defineunderweight, healthy weight, overweight, andobesity?

Answer 6

underweight: body weight less than healthy weight range (BMI less than 18.5)
healthy: body weight within range (18.5 to 24.9)
overweight; body weight greater than weight range considered healthy (25 to 29.9)
obese: too much body fat with adverse health effects (BMI 30 or more)

Question 7

What are the health risks of too little and too much body fat? (with an emphasis oncentral obesityand its associated health risks)

Answer 7

Underweight - unable to preserve lean tissue during wasting disease, medical stresses, menstrual irregularities, infertility in women, osteoporosis, bone fractures
Overweight - diabetes, HTN, CVD, sleep apnea, respiratory problems, osteoarthritis, cancer, gallbladder disease, complications in pregnancy, surgery

Question 8

What are the common methods used to assess body fat?

Answer 8

Diet, medical history, physical examination, and lab tests.

Fat Fold measures, air displacement, bioelectrical, DEXA