2.4 Making healthy choices

• Biologie
• Middelbare school
• vmbo lwoo, vwo
• Leerjaar 2

Welcome everyone 

 Think about...

• Take off your coat, hat off.
• Mobile in the phone bag (on silent).
• Book (laptop) + notebook, pen on the table. Bag on the floor.
• Sit in your own place!
• You can eat and drink in the canteen.
• 5 minutes.

schedule 

• under the dome project          15 mins 
• Previous lesson                           10 min 
• Explanation 2.4                            10 min.
• Doing assignments       
• Working on poster 
• Closing                                              5 min. 

Why chew?

Chewing creates a bigger surface area.

bigger surface area = more surface where digestive juices can do their job = more and quicker digestion

surface area of 6 cm2

surface area of 1,5 cm2

together 12 cm2

EMULSIFICATION

• by bile salts
• devides larger globules of fat into smaller ones
• increasing surface area for enzyme lipase from pancreas

1

2

3

4

5

6

7

8

heart

large intestine

small intestine

stomach

lung

liver

brain

kidney

The digestive system

Enzymes

Peristalsis

Learning goals 2.4

At the end of this lesson..

• You can use the Wheel of Five to give advice about a healthy diet.
  
• You know what a healthy weight is and what choices can help maintain it.
  
• You can name the possible causes and consequences of eating disorders and give a few examples.

Energy in food

Food contains energy
Energy can be measured

• Joule (J)
• Calorie (cal)
• 1 cal = 4,2 J
• 1 kcal = 4,2 kJ

Talking point 

When you watch tv, go to the supermarket or read a magazine containing advertisements, you will be confronted with food and making choices. 

• Discuss healthy eating by explaining to another student what you think is healthy eating, and why. 
• Listen to another student’s explanation about healthy eating, and try to ask a couple of questions about his or her ideas.

Energy requirement

Energy requirement = How much energy (kcal) a person needs

• Age
• Body size
• Sex
• Physical activity

Over/underweight

Healthy = Every day you eat cal according to your energy requirement

Losing weight = Every day you eat fewer cal than your energy requirement

A lot of this leads to > underweight

Gaining weight = Every day you eat more cal than your energy requirement. A lot of this leads to > overweight

Eating disorders

Anorexia nervosa:  lose extreme amounts of weight

Bulimia nervosa:  vomit to get rid of the food, use large amounts of laxatives

Binge eating disorder: moments of eating a lot 

Doing assignments 

Read basic 2.4  

Make assignment 1 until 10 

5 min ZS 

FOOD GROUPS:

Foods that contain the same type of nutriënts belong to a food group. 

• Fruit and vegetables vitamins/minerals 
• Potatoes, bread, rice, pasta and other starchy carbohydrates
  
• Beans, pulses, fish, eggs, meat and other proteins/minerals
• Dairy and alternatives 
• Oils and spreads Fats

Fruits and Vegetables:

Fruit and vegetables should make up just over a third of the food we eat each day.

Aim to eat at least five portions of a variety of fruit and vegetables each day.
 Choose from fresh, frozen, canned, dried or juiced.  

Potatoes, bread, rice, pasta and other starchy carbohydrates:

Why choose wholegrain?

Wholegrain food contains more fibre than white or refined starchy food, and often more of other nutrients. We also digest wholegrain food more slowly so it can help us feel full for longer.

Remember, you can also purchase high fibre white versions of bread and pasta which will help to increase your fibre intake.

Beans, pulses, fish, eggs, meat and other proteins:

These foods are sources of protein, vitamins and minerals, so it is important to eat some foods from this group.

Beans, peas and lentils (which are all types of pulses, sometimes called ‘legumes’) are good alternatives to meat because they’re naturally very low in fat, and they’re high in fibre, protein and vitamins and minerals. Other vegetable-based sources of protein include tofu, bean curd and mycoprotein.

im for at least two portions (2 x 140g) of fish a week, including a portion of oily fish. Most people should be eating more fish, but there are recommended limits for oily fish, crab and some types of white fish

Dairy and alternatives:

Try to have some milk and dairy food (or dairy alternatives) such as cheese, yoghurt.

These are good sources of protein and vitamins, and they’re also an important source of calcium, which helps to keep our bones strong.

Some dairy food can be high in fat and saturated fat, but there are plenty of lower-fat options to choose from.

Oils and spreads:

Although some fat in the diet is essential, generally we are eating too much saturated fat and need to reduce our consumption.

Unsaturated fats are healthier fats that are usually from plant sources and in liquid form as oil, for example vegetable oil, rapeseed oil and olive oil.

Swapping to unsaturated fats will help to reduce cholesterol in the blood, therefore it is important to get most of our fat from unsaturated oils.

Choosing lower fat spreads, as opposed to butter, is a good way to reduce your saturated fat intake.

Remember that all types of fat are high in energy and should be limited in the diet.

Complication (p.70)

Talking about what is healthy eating, is a delicate topic. People are different, have different activities and and need different amounts of food and nutrients.. This makes it difficult to provide guidance on healthy eating that is suitable for everybody. Another reason for confusion is that scientific research and discovering what is healthy or not is complicated, because people are unique and there are many factors that affect our health. 

Most health centres like the Dutch ‘Voedingscentrum’ will only embrace new ideas when they have been scientifically proven, which usually takes years. A third problem is the food industry, which is mainly motivated by increase in sales. Therefore, healthy diet advice from their point of view is not always objective, and you have to be suspicious of the promises that are found on many new products.

Light products often contain more carbohydrates while they contain less fats. Sometimes this means that you ingest more energy when choosing the light product. Some light products contain less sugar, while other substances are added to make them taste sweet. When looking at products containing fat, like butter, margarine contains less healthy fats, while it is advertised as the better choice. Real butter (dairy butter) contains a great variety of fats. However, we do need both saturated and unsaturated fats to stay healthy.

Body Mass Index 

• Instead of looking at weight/height alone, nutritionists look at ideal body size. 
• Combining weight (mass) and height in a number called the BMI.

Body mass index

Dietary Choices:

• vegetarian
• vegan
• pescetarian

Hygiene and safety 

• Date on food
• Frozen/dried foods
• Vacuum packed foods
• Clean utensils (spoon, knives etc)