Energy balance of the body. The quantitative and qualitative requirements of food. The regulation of food intake. Control of body weight

Question 1

Metabolism definition

Answer 1

Chemical reactions in the body.

Require fuel or energy to be maintained

Question 2

Energy content of carbs, fat, proteins

Answer 2

Carbohydrate: 17 kJ/gram
Fat: 39 kJ/gram
Proteins: 17 kJ/gram

Question 3

1 Calorie

Answer 3

4.2 Joules

Question 4

TEE means?

Answer 4

Total energy expenditure

Question 5

Neutral energy balance definition

Answer 5

When TEE is equal to the total energy content of food intake

Question 6

Negative energy balance

Answer 6

Weight loss

Question 7

TEE can be measured by

Answer 7

TEE = heat production + external work
Heat production = BMR + DIT (Diet-induced Thermogenesis)
By measuring a persons oxygen consumption
1 L of oxygen = 21 kJ of energy

Question 8

Basal metabolic rate

Answer 8

the minimal energy expenditure required to exist. is considered to be referring to the awake state and without any physical activity.

Question 9

BMR measurement

Answer 9

Measurement of BMR
● Usually measured in the morning
● No physical activity is allowed
● Neutral temperature (20 C)
● No food (8-12 hours before measurement)
● No emotional stress/stimuli
● No drugs

Question 10

Normal BMR values

Answer 10

● Based on body surface area: 170 kJ / square meter / hour
● Women: 6000 kJ/ day
● Men: 7000 kJ/ day

Question 11

BMR is influenced by

Answer 11

● Body size, but this is complex. Surface area yields a more linear relationship than size.
● Sex: women usually have more body fat and less muscle, and the basal metabolic rate is different
between fat and muscle
● Age: BMR declines with age
● Body temperature: BMR is higher with a fever
● Climate
● Pregnancy
● Thyroid hormones and Catecholamines both increase the BMR. Discussed in other topics.
● Drugs, stress, certain injuries, and so on

Question 12

TEE parts

Answer 12

● Normally, BMR is 50-70% of total energy expenditure
● Diet induced thermogenesis (DIT) accounts for roughly 8-15% of TEE. After a person eats, GI
motility and secretions use a lot of energy
● Energy expended in physical activity is 15-30% of TEE if a person doesn’t do a lot of heavy work,
but of course, depends largely on lifestyle

Question 13

Brown adipose tissue

Answer 13

Brown adipocytes contain less fat and numerous
mitochondria that give them their darker color and thermogenic function.
Brown adipocyte mitochondria
contain uncoupling protein (UCP1) , a transmembrane protein that allows H + ions to flow from the
intermembrane space to the matrix, thus decreasing the proton gradient necessary for ATP synthase to
phosphorylate ADP, and allowing heat production*.

Question 14

The regulation of food intake. Control of body weight

Answer 14

A satiety center inhibits appetite even in the presence
of food, and there is also a feeding center with the opposite effect.
Information feeds into these two centers from the arcuate nucleus.
The arcuate nucleus has various neurons that
project onto the satiety feeding centers, these being anorexigenic and orexigenic neurons.
Anorexigenic neurons release POMC which leads to decreased appetite,
Orexigenic neurons release neuropeptide Y to cause increased appetite.

Question 15

Hunger Decreased By

Answer 15

■ GLP-1 (Glucagon-like peptide 1) secreted by intestinal cells and stimulates insulin
secretion
■ Peptide YY : secreted by intestinal cells following a meal, inhibits ghrelin secretion
and directly acts on hypothalamus
■ CCK (cholecystokinin)
■ CART (Cocaine-and-Amphetamine Regulated Transcript)

Question 16

Hunger Increased By:

Answer 16

■ Ghrelin (Growth hormone releasing hormone): secreted by gastric cells
■ Orexins : stimulate hunger and awakeness, help fight against sleep