Energy Metabolism, Food Intake and Weight Loss

Question 1

What is the result of energy intake chronically exceeding energy expenditure by just 25kcal per day?

Answer 1

Morbid obesity

Question 2

What are the different forms of energy?

Answer 2

Chemical, Mechanical, Electrical

All of which can be converted to heat

Question 3

What is the ‘FIrst Law of Thermodynamics’?

Answer 3

Energy cannot be created or destroyed, but it can be transformed from one form into another.

Question 4

Give an example of chemical work?

Answer 4

Synthesis of new macromolecules

Question 5

Give an example of mechanical work

Answer 5

Muscular contraction

Question 6

Give an example of electrical work

Answer 6

Maintenance of ionic gradients across membranes; eg the sodium-potassium pump.

Question 7

What is the formula for energy balance?

Answer 7

ENERGY BALANCE = energy intake (+ energy stores) - energy expenditure

Question 8

What is negative energy balance?

Answer 8

Utilisation of the body’s energy stores: glycogen, fat, protein.

Question 9

What is positive energy balance?

Answer 9

An increase in body energy stores, primarily as fat.

Question 10

What is energy consumed in the form of food and drinks stored as?

Answer 10

• Glycogen in the liver and muscles

- Fat (accounting for majority of energy storage)

Question 11

When energy is in short supply, where can the body source energy from?

Answer 11

• Glycogen in liver and muscles
• Fat
• Protein (last resort- cases or starvation or malnutrition)

Question 12

What is the 2nd Law of Thermodynamics?

Answer 12

All energy used by the body degenerates as heat.

ie Whenever energy is transferred or transformed (eg during cellular metabolic reactions) there is a loss of energy in the form of heat.

Question 13

What is a calorie?

Answer 13

The amount of heat required to raise the temperature of 1g of water by 1 degree celsius

Question 14

How many calories are in

a) 1g Carbohydrate
b) 1g Protein
c) 1g Fat
d) 1g Alcohol
e) 1g Fibre

Answer 14

a) 4 kcal
b) 4kcal
c) 9kcal
d) 7kcal
e) 2kcal

Question 15

What is the energy ‘currency’ used to fuel cell processes?

Answer 15

ATP (Adenosine Triphosphate)

Question 16

What is the name of the organelles responsible for energy (ATP) production?

Answer 16

Mitochondria

Question 17

What are the key nutrients (cofactors) needed to fuel ATP generation via Acetyl CoA formation, Krebs Cycle and Electron Transport Chain?

Answer 17

Magnesium 
Manganese
Iron
Sulphur
CoQ10
Copper
B1, B2, B3, B5
Alpha-lipoic acid

Question 18

Name 5 factors that contribute to ATP production

Answer 18

• Sufficient nutrient intake
• Digestion & Absorption
• Mitochondrial Health
• Thyroid health
• Healthy Detoxification

Question 19

What does BMR stand for and what is it?

Answer 19

Basal Metabolic Rate

It is the minimum level of energy required to sustain life

Question 20

Name 4 factors that affect BMR

Answer 20

• Age
• Stress
• Fever
• Caffeine

Question 21

What nutrient deficiencies may lead to hypothyroidism?

Answer 21

Iodine, Selenium, Zinc, Vitamin D,

Question 22

What is the Thermic Effect of Food (TEF)?

Answer 22

TEF is the amount of energy required to digest and process the food you eat.

Question 23

What are the Thermal effects of fats, carbs and proteins?

Answer 23

Fats = 0 - 3%
Carbohydrates = 5 - 10%
Proteins = 20-30%

Question 24

What is de novo lipogenesis (DNL)?

Answer 24

The metabolic pathway that synthesises fatty acids from excess carbohydrates

Question 25

What diseases may benefit from a Ketogenic diet?

Answer 25

Obesity, metabolic syndrome, type 2 diabetes, Alzheimer's, Parkinson's and certain cancers. Effective in preventing epileptic seizures

Question 26

What are the following digested into? Carbohydrates Proteins Fats

Answer 26

Carbohydrates -> Glucose Proteins -> Amino Acids Fats -> Fatty acids

Question 27

Name 8 of the hormones/neurotransmitters which affect food intake and state if they increase or decrease appetite.

Answer 27

Neuropeptide Y (NPY) - increases appetite Cholecystokinin (CCK) - decreases appetite Insulin - decreases appetite Glucagon - decreases appetite Glucagon-like peptide 1 (GLP-1) - decreases appetite Bombesin - decreases appetite Ghrelin - increases appetite Leptin - decreases appetite

Question 28

Why is CCK secreted?

Answer 28

It is secreted in the response to food in the duodenum. Meals rich in protein and fat stimulate CCK more than meals that just contain carbohydrates.

Question 29

What is the role of insulin in the body?

Answer 29

- To lower blood glucose by storing in the muscle tissue and liver as glycogen - It is responsible for controlling the storage and release of fatty acids. Fat cannot be stored without insulin.

Question 30

How is storage and release of fatty acids achieved?

Answer 30

1. The regulation of several lipases enzymes | 2. The activation of glucose transport into the fat cells via recruitment of glucose-transport protein 4 (GLUT4)

Question 31

Name the roles/metabolic actions of insulin in the body

Answer 31

- Stimulates synthesis of triglycerides from free fatty acids - Increases synthesis of liver glycogen - Inhibits gluconeogenesis - Stimulates glucose uptake in skeletal muscle - Reduces hunger via hypothalamus

Question 32

What is gluconeogenesis?

Answer 32

The biosynthesis of glucose from non-glucose precursors

Question 33

What is a typical feature of insulin resistance and what are the side effects of this?

Answer 33

Central adiposity is a typical feature and can produce inflammatory cytokines, promoting further hormone resistance, obesity and chronic diseases.

Question 34

How does the liver metabolise fructose differently to glucose?

Answer 34

When glycogen stores are full, fructose is converted directly to liver fat. This can lead to NAFLD, obesity, gout

Question 35

What factors can impact ghrelin secretions?

Answer 35

Dysregulated sleep and elevated cortisol can increase secretions Exercise has been shown to decrease them

Question 36

What are some effects of Leptin Resistance?

Answer 36

Excess leptin can modify insulin sensitivity, tissue metabolism, stress responses and reproductive function. Leptin resistance leads to failure of suppressing the appetite

Question 37

Name some factors that can increase leptin sensitivity:

Answer 37

- Go Gluten-free - Reduce sugar consumption - Support gut flora with probiotics - Reduce inflammation - Regular exercise - Sleep hygiene

Question 38

List 4 functions of prebiotics in Energy Metabolism

Answer 38

- Promote satiety - Reduce hunger - Reduce food ingestion - Suppress ghrelin

Question 39

What are prebiotics?

Answer 39

A non-digestible carbohydrate. that promotes the growth of beneficial gut bacteria.

Question 40

What are probiotics?

Answer 40

Microorganisms introduced into the body for their beneficial health properties.

Question 41

What are some factors affecting food intake?

Answer 41

- Cultural/social - meal patterns, religious traditions, attitude to food left on plate - Sensory - appearance/ smell of food, packaging/advertising, addiction - Emotional - stress, sadness, loneliness - Other - hormones, disease states, medications, cost

Question 42

What strategies may help maintain stable blood sugars?

Answer 42

- Include protein with every meal - Avoid refined carbs/sugar and include more complex carbs/low GI foods - Choose organic/whole foods - Chew well, eat mindfully, don't overeat, 3 meals a day

Question 43

Name 5 factors that can hinder weight loss

Answer 43

- Overeating and junk food - Sedentary lifestyle - High blood sugar - Chronic stress - Poor sleep

Question 44

What is EPOC?

Answer 44

Excess Post-exercise Oxygen Consumption - oxygen intake increases post exercise.

Question 45

Explain what oxygen debt means.

Answer 45

This is when an activity performed uses energy faster than the rate at which the body can supply oxygen.