Energy Balance

Question 0

Energy densities of macronutrients

Answer 0

1kcal=4.184kJ 
Carbohydrate 4kcal=17kJ per g
Protein 4kcal=17
Fat 9=37
Alcohol 7=29.5

Question 1

Define energy balance

Answer 1

Equals energy intake-expenditure
Positive-> obesity, growth, pregnancy, recovery from depletion
Negative-> wasting disease, anorexia, starvation, voluntary weight loss

Question 2

Ways of estimating energy intake

Answer 2

Bomb calorimeter-> food ignited in the presence of O2-> heat combustion is measure from a rise in water temp
Determine amount of food eaten-> weighed record, dietary record, recall questionnaire
Energy/nutrient context-> direct analysis of food, urine and faeces

Question 3

Components of energy expenditure

Answer 3

Basal metabolic rate-> 60-70% of total energy expenditure
Physical activity-> 25-30%
Diet induced thermogenesis->10%, increased after a meal

Question 4

Thermic effect of exercise and illness

Answer 4

Exercise
Sedentary-> 10% 
Athlete-> 15-30% 
Illness 
Partial starvation-> -10-40
Post operative +10
Server infection-> +30-60
Third degree burns-> +50-100

Question 5

Diet induced thermogenesis

Answer 5

Obligatory:
Protein-> 20-25% 
CHO-> 5-7% 
Fat-> 2-4% 
Adaptive-> increase in CNS activity due to CHO

Question 6

Indirect calorimetry

Answer 6

Calculates the amount of energy expended by measuring the amount of O2 utilised

Question 7

Determining energy expenditure and substrate conc from indirect calorimetry

Answer 7

Respiratory quotient-> fuel+O2=H2O+energy
Respiratory exchange ratio-> ratio of the rate of CO2 produced to the rate of O2 expenditure vCO2/vO2
Indicates suburbs grate oxidation->relative amounts of carbs and fats being oxidised for energy production
Carbs RER=1
Fat RER=0.7

Question 8

Body composition, fat

Answer 8

Fat mass-> adipose
Fat free mass->lean body mass
Male:
Normal-> 15-22
Overweight-> 25-30
Obese-> >30 
Female
Normal-> 22-28
Fat-> 30-35
Obese-> 35
Main energy store in fat

Question 9

Body density

Answer 9

Under water weighing

Question 10

Body water

Answer 10

Isotope dilution

Question 11

Body fat

Answer 11

Skin fold thickness
Dual energy x ray
Absorptionetry

Question 12

Anthropometry

Answer 12

Weight, height, circumference
BMI=weight/height2 should be 20-25
Waist hip ratio
Waist circumference