Lesson 1 - Nutrition and Energy

Question 1

Why do we eat?

Answer 1

The nutrients we get from our food is converted into chemical energy that our bodies use to grow, build and repair tissues, and produce energy.

We get nutrients from:
- Plant sources
- Animal sources

Question 2

How does our body use nutrients?

Answer 2

Catabolism: the metabolic reactions that break down larger molecules into smaller subunits

Anabolism: the metabolic reactions that use energy to produce larger molecules from smaller subunits

Metabolism: the set of chemical reactions that occur in living organisms that are necessary to maintain life

Question 3

Calculating metabolic rate

Answer 3

Metabolic Rate: the rate at which the body converts stored energy into working energy

Basal Metabolic Rate (BMR): Energy(kJ) requirements at rest

Female: BMR = [655 + (9.6 X mass in kilograms) + (1.8 X height in centimeters) — (4.7 x age in years)] x 4.18

Male: BMR = [66 + (13.7 x mass in kilograms) + (6.0 X height in centimeters) — (6.8 X age in years)] x 4.18

Question 4

What is a Calorie?

Answer 4

calorie (J): the amount of energy needed to raise the temperature of 1 g of water by 1 °C (4.18 J)

Calorie (kJ): 1 Calorie = 1000 calories (4180 J)

What does that mean?
- Running: ~60-100 °C/ hour
- A litre of gas contains 11000-12000
Calories (about 10km)
- An iPhone uses 8200 J/ hour or ~2
Calories

Question 5

What are Carbohydrates?

Answer 5

Carbohydrates are the main source of energy for the human body.

In a healthy diet they are ~55% of a person’s energy requirements (significant sources in
fruits and vegetables, grains)

Carbohydrates are made up of carbon, hydrogen, and oxygen

There are three main types: monosaccharides, disaccharides, and polysaccharides

Question 6

What is Protein?

Answer 6

Proteins are one of the key building blocks of cells and perform a wide range of functions (structural, enzyme, and hormones)

Proteins are made up of smaller molecules called amino acids. There are 20 amino acids, and our bodies can make 12 of them. The 8 that must be obtained from food sources are called essential amino acids.

The average adult needs ~60g of protein, but this only accounts for 10- 30% of energy requirements (significant sources include eggs, fish, meat, cheese, beans, lentils, seeds, nuts).

Animal proteins contain all 8 essential amino acids, but plant proteins do not. Vegans and vegetarians need to consume a variety of plant proteins and larger quantities to stay healthy

Question 7

What are Lipids?

Answer 7

Lipids are a key source of energy, help in the absorption of vitamins, and serve as insulation for the body.

In our diets, we see lipids in the form of fats and oils, which are made of triglycerides.

Triglycerides can be saturated (saturated fats) or unsaturated (unsaturated fats) depending on their structure

Saturated fats are usually solid at room temperature (think butter, fat on cuts of meat)

Unsaturated fats are called oils and tend to be liquid at room temperature (e.g. olive oil, fish oils) and are generally healthier than saturated fats

Question 8

What are Water, Vitamins and Minerals?

Answer 8

Water is needed for chemical reactions, to digest food, and to eliminate waste products. The average person needs about 2L of water/ day

Vitamin: an organic molecule that the body requires in small amounts as an essential nutrient
- Fat soluble (Vitamin A, D, E, K)
- Water soluble (Vitamin B, C)

Mineral: an element, such as calcium or iron, required by the body in small amounts; plays a role in cell processes and repair
- Calcium – bone formation
- Iron- oxygen transport in blood cells