Topic 4: Nutrition, Diet & Body weight

Question 1

What are the components of daily energy expenditure?

Answer 1

• Basal metabolic rate
• Voluntary physical activity
• Diet-induced thermogenesis

Question 2

What is the definition of basal metabolic rate?

Answer 2

Measure of basal energy required to maintain the functioning of the various tissues of the body at physical, digestive and emotional rest

Question 3

What is a approximated value of BMR?

Answer 3

In individuals who are not obese: multiplying the body weight in kg by 100

Question 4

What is the definition of voluntary physical activity?

Answer 4

Energy required by skeletal and cardiac muscle for voluntary physical activity

Question 5

What is an approximated value of energy needed for voluntary physical activity?

Answer 5

• Sedentary: BMR + 30% of BMR
• 2h of moderate exercise a day: BMR + 60-70% of BMR
• Several hours of heavy exercise a day: BMR + 100% of BMR

Question 6

What is the definition of diet-induced thermogenesis?

Answer 6

Energy needed to digest, absorb, distribute and store nutrients

Question 7

What is an approximated value of diet-induced thermogenesis?

Answer 7

10% of energy content of ingested food or sum of BMR and energy required for amount of time spent in physical activity

Question 8

What are the essential components of the diet?

Answer 8

• Macronutrients: carbohydrate, fat and protein
• Micronutrients: vitamins and minerals
• Water
• Dietary fiber

Question 9

Why are carbohydrates essential?

Answer 9

They are major energy containing components of the diet

Question 10

Why are fats essential?

Answer 10

• Yields more energy than carbohydrates or protein
• Required for absorption of fat-soluble vitamins (A D E and K)
• Provide essential fatty acids (linoleic and linolenic acids) which cannot be synthesised in the body

Question 11

Why are proteins essential?

Answer 11

• Made of amino acids which are necessary for structure and function of the body
• 9 essential amino acids cannot be synthesised and must be obtained from diet
• Some are conditionally essential (arginine, tyrosine and cysteine during pregnancy or for children)

Question 12

Why is water essential?

Answer 12

• Maintain the body’s fluid balance

Question 13

Why is dietary fibre essential?

Answer 13

Non-digestable plant material such as cellulose is necessary for normal GI tract function
- Reduces cholesterols and rise of diabetes

Question 14

Why are minerals essential?

Answer 14

• Electrolytes establish ion gradients across membranes and maintain water balance
• Essential for structure (bone and teeth) - Calcium
• Signalling molecule (calcium)
• Enzyme co-factors (iron, magnesium, copper)
• Essential component of haemoglobin (iron)

Question 15

Why are vitamins essential?

Answer 15

• If inadequate intake = deficiency diseases
• D: rickets
• E: neurological abnormalities
• B12: anaemia
• C: scurvy
• Folate: Neural tube defects
• If in excess - can be toxic

Question 16

What are the clinical consequences of protein and energy deficiency in humans?

Answer 16

• Lead to malnutrition
• Inbalance between what an individual eats and what that individual needs to maintain health
• Spectrum of clinical conditions seen in starving adults and children
• Marasmus and Kwashiorkor

Question 17

What is Marasmus?

Answer 17

• Protein-energy malnutrition
• Commonly seen in children <5yo
• Muscle wasting and loss of body fat
• No oedema
• Thin and dry hair
• Diarrhea is common
• Anaemia may be present

Question 18

What is Kwashiorkor?

Answer 18

• Young child displaced from breastfeeding and fed with some carbohydrate and low protein
• Lethargic and anorexic (loss of appetite)
• Pitting oedema (indentation left behind when pressure is applied)
• Abdomen is distended due to hepatimegaly (enlarged liver) or ascites (accumulation of fluid in peritoneal cavity)
• Serum albumin is low
• Anaemia is common

Question 19

How to determine the body mass index of a patient?

Answer 19

BMI = weight (kg) / height square (m square)

Question 20

How do you interpret the values of BMI?

Answer 20

• Underweight <18.5
• Desirable range 18.5 to 24.9
• Overweight 25 to 29.9
• Obese 30 to 34.9
• Severely obese >35

Question 21

What is the definition of obesity?

Answer 21

• Excessive fat accumulation in adipose tissue

- BMI >30

Question 22

What are the factors involved in the regulation of body weight?

Answer 22

• Food choices
• Eating behavior
• Lifestyle

Question 23

What is sucrose?

Answer 23

Disaccharide of glucose and fructose

Question 24

What is lactose?

Answer 24

Disaccharide of galactose and glucose

Question 25

What is starch?

Answer 25

Polymer of glucose

Question 26

What is maltose?

Answer 26

Glucose disaccharide

Question 27

What is glycogen?

Answer 27

Polymer of glucose, carbohydrate storage molecule in animals

Question 28

What are the essential amino acids that cannot be synthesised and must be obtained from diet?

Answer 28

If - Isoleucine 
Learned - Lysine 
This - Threonine 
Huge - Histidine 
List - Leucine 
May - Methionine 
Prove - Phenylalanine 
Truly - Tryptophan 
Valuable - Valine

Question 29

What are chronic diseases for which obesity is a risk factor?

Answer 29

• Hypertension
• Type 2 diabetes
• Cardiovascular disease
• Gall bladder disease
• Osteoarthritis
• Cancer