MCBG Session 4 - Nutrition, Diet & Bodyweight

Question 1

What is energy?

How is energy provided for various bodily reaction to occur?

Answer 1

• Energy = The capacity to do work

- The bond between the beta and gamma phosphate in ATP is cleaved.

Question 2

What is the standard unit of food energy?
What is a calorie?
How many KJ in a Kcal?

Answer 2

• Standard unit = Kj
• Calorie = Energy required to raise 1g of water by 1 degree C
• 1 Kcal = 4.2Kj

Question 3

What are the main essential compounds in the diet?

Answer 3

• Carbohydrates
• Proteins
• Fats
• Minerals (essential)
• Vitamins (essential)
• Water
• Fibre

Question 4

What is the general formula of a carbohydrate?

What are the 4 main kinds of carbohydrate, give examples.

Answer 4

• (CH2O)n

1) Monosaccharide (1 unit) - e.g.: glucose
2) Disaccharide (2 units) - e.g.: fructose
3) Oligosaccharides (3-12 units) - e.g.: dextrins
4) Polysaccharides (10-1000’s units) - e.g.: starch

Question 5

Why is fibre important in the diet?

Answer 5

• Reduces risk of bowel cancer

- Lowers plasma cholesterol by binding to bile salts in GIT

Question 6

What do proteins consist of?

How many AA’s are there? How many are “essential”?

Answer 6

• Linear chains of AA’s

- 20 AA’s exist, 9 are essential (cannot be made endogenously) and must be consumed through diet.

Question 7

What do fats consist of?
Why do they yield more energy than carbs and proteins?
What are they required for?

Answer 7

• Triacylglycerols (3 fatty acids esterified to 1 glycerol)
• Because they contain much less oxygen
• Absorption of fat soluble vitamins (A,D,E,K) from gut and provide essential fatty acids such as lineolic acid.

Question 8

Although energy requirements depend on age, sex, body composition and physical activity level - what is the average energy requirement for a 70kg male and a 58kg female?

Answer 8

• 70kg male = 12,000 Kj/day

- 58kg female = 9,500 Kj/day

Question 9

What 3 things is daily energy expenditure a sum of?

Answer 9

• Basal Metabolic Rate (BMR)
• Physical Activity Level (PAL)
• Diet-induced Thermogenesis (DIT)

Question 10

What occurs if energy intake is equal to expenditure?
What happens if intake is higher than expenditure?
What happens if intake is lower than expenditure?

Answer 10

• Body weight stays stable
• Energy stores (fat) increases
• Energy stores (fat) decreases

Question 11

What is obesity?

What are the associated risks?

Answer 11

• An accumulation of fat in adipose tissue, and a BMI of over 30.
• Increased risk of CVD, cancer & type 2 diabetes

Question 12

How is BMI calculated?

What are the value ranges for underweight, normal, overweight, obese and severely obese?

Answer 12

• BMI = Kg/M^2
• <18.5 = underweight
• 18.5-24.9 = normal
• 24.9-29.9 = overweight
• 30.0-34.9 = obese
• > 35 = severely obese

Question 13

What is a greater proportion of upper body fat linked with?

Answer 13

An increased risk of:

• Insulin resistance
• Type 2 diabetes
• Hypertension
• Stroke
• Premature death