Unit 5L.4: as an energy source Balanced diet Requirements for different lifestyles Science skills: Observing Classifying By the end of this unit you should: Know that humans require food as an energy source. Estimate energy intake and output. Know that a balanced diet must contain proteins, fats, carbohydrates, vitamins and fibre. Know what is meant by a healthy diet. 1
5.7.1 5.7.2 as an Energy Source You need food to make your muscles and other organs work. provides you with different nutrients that give you the energy you need to keep going. Just like a car won t start without petrol, your body won t work without food. gives us the energy to carry out our activities. Measuring energy in food: We can measure the energy content in food by burning it. UActivity 1 Teacher Demonstration Equipment: Test-tube Thermometer Stand Mounted needle Peanut Water Measuring cylinder Lighter/ matches 2
Steps: *UTeacher demonstratesu, students can take measurements 1. Use a measuring cylinder to pour 20 ml of water into test tube. 2. Place a thermometer inside the tube and record the temperature in the table below. 3. Place the peanut at the end of the mounted needle. 4. Ignite the peanut and hold under the test tube to heat the water. Begin the timer. 5. When the water reaches its maximum temperature, stop the timer and record the temperature and time. Starting temperature Maximum temperature Time As the food burns, it gives out energy. The hotter the water gets the more energy is in the food. Most foods you buy have their energy content on the label. 3
You can examine the food labels of the manufactured food you eat to calculate your average daily energy intake. Energy Value (Calories) butter 499 sugar 389 white bread 266 margarine 620 potato, baked 89 hash browns 257 beef burger (no cheese) 275 fried fish 221 oranges, raw 47 lentils, boiled 116 carrots, raw 41 eggs, fried 201 cheese pizza 14" 257 chocolate chip cookies, low fat 453 cola carbonated drink 37 corn flakes, breakfast cereal 360 Activity 2: Using the table above what would be the total energy intake if you consumed the following foods? White bread Hamburger Oranges Chocolate chip cookies, low fat Cola carbonated drink TOTAL: 4
How much food do we need? The amount of food you need depends on how much energy you use every day. The amount of energy you need varies according to: your body size how active you are how fast you are growing Energy Intake Energy Output Energy intake is the amount of energy you get in your food in a day. Energy output is the amount of energy your body uses up in a day. What happens if we eat too much? If you eat more food than your body needs, your body will store the extra calories as fat. If you want to stay healthy you have to think about your daily energy intake and the energy output. 5
Key terms: Energy Energy intake Energy output Key ideas: is an energy source Energy intake is the amount of energy you get from your food in a day. Energy output is the amount of the energy your body uses in a day. Key question: Complete the following: is a good source of. The amount of energy you need depends on;,, and What happens if the body s intake is greater than the output?.. Project: Research the energy output for various daily exercises. Record a diary of your energy input and output for one day. Find the approximate calories for the foods you consumed. Does your intake match your output? 6
5.7.3 5.7.4-5.7.5 Balanced Diet provides you with different nutrients that give you the fuel needed to keep your working. A diet is made up of everything you eat and drink. A balanced diet must include carbohydrate, fat, protein, vitamins, minerals and fibre. A. Carbohydrates: Carbohydrates are the body's most important and readily available source of energy. Carbohydrates are a necessary part of a healthy diet for both children and adults. The two major forms of carbohydrates are: Simple sugars (simple carbohydrates), such as glucose. Starches (complex carbohydrates), found in foods such as starchy vegetables, grains, rice, breads and cereals. B. Fats: The body uses fat as a fuel source, and fat is the major storage form of energy in the body. 7
There are two main types of fat found in food: saturated and unsaturated. Saturated and unsaturated fat contain the same amount of calories. As part of a healthy diet, we should try to cut down on food that is high in saturated fat. Eating a diet high in saturated fat can cause the level of cholesterol in your blood to build up over time. Raised cholesterol increases your risk of heart disease. A healthy diet cuts down on the total amount of fat, but also reduces the intake of saturated fat. s high in saturated fat include: fatty cuts of meat meat products, including sausages and pies butter, oil and lard 8
cheese, especially hard cheese cream, soured cream and ice cream some savoury snacks and chocolate confectionery biscuits, cakes and pastries. Unsaturated fat: Having unsaturated fat instead of saturated fat can help lower blood cholesterol. Unsaturated fats are found in: oily fish such as salmon, fresh tuna and mackerel avocados nuts and seeds sunflower and olive oils. C. Proteins: Our body needs a lot of protein especially young people because they are growing. The best sources are beef, chicken, fish, 9
eggs, dairy products, nuts, seeds, and legumes like black beans and lentils. Your muscles, organs and your immune system are made up mostly of protein. D. Fibre: Fibre is the part of food that you cannot digest. Fibre is found in plants it helps clean out your intestines by helping to move contents along through the bowel. It's important to eat fibre so try some bran muffins instead of chocolate. Another way to get fibre is to eat whole-meal foods, brown rice, fruit, and oats. E. Vitamins and Minerals: Fresh fruit and vegetables contain special substances called vitamins. Different vitamins help our bodies in various ways as shown in the table below. 10
Vitamin What it is needed for Examples Vitamin A Helps your eyesight Vitamin B Activates the body Vitamin C Keep your skin and gums healthy Vitamin D Helps you take in the minerals you need 11
In addition to vitamins, our body also needs minerals such as calcium and iron. Mineral What it is needed for Examples Calcium For strong bones and teeth Iron Makes red blood cells F. Water: The foods we eat contains a lot of water. Water is an important part of every living organism. A balanced diet also means providing the body with sufficient water. We get water from the food eat, plants and animals, but also from the water we drink. 12
An apple might not look 5% Solids 95% Water like a drink, but most of it is water. UWater is important: Helps you digest the food Helps keep your body temperature stable. Activity 3: Choose one of the following essential elements of a balanced diet to put into the KWHL chart. UProtein, fat, carbohydrate, fibre, water or vitamins and mineralsu. K (Know) W (What) H (How) L (Learn) ie. Vitamins can be found in tablets 13
Activity 4: Many people eat too much. Eating a lot does not mean that someone is eating properly. You will need: labels for a range of packaged snack foods (biscuits, chips, muesli bar etc). Analyse the labels and find the quantities of protein, carbohydrate and fat found in the food snack. Snack Protein (g) Carbohydrate (g) Fat (g) Which snack is the healthiest for your lunchbox? List any other nutrients mentioned on the label.. A healthy diet: provides a balance of all the nutrients needed for the body. 14
Pyramid: The food pyramid can help guide you to make good choices for your diet. The bread and cereal group is at the bottom of the pyramid. The body needs more of the carbohydrate food group to provide enough energy for daily activities in the diet. The body requires smaller amounts from each food group the further up the pyramid levels. The fat group is at the top of the pyramid. This means that the body needs small amounts of fat in the diet. Fat Group Dairy Group Meat Group Vegetable Group Fruit Group Bread and Cereal Group 15
Nutritional labels inform people of the content in foods to help make suitable choices for their body. A typical nutrition label compares key nutrients and serving sizes. Some labels include information on percentage daily intake and promote nutrition or health benefits too. Example of nutrition information for fruit bread. Use the information in the table above to answer the following questions; 1. What are the total sugars per serve of bread?... 2. If you ate the whole packet of bread how much fat would you have eaten?... 16
Activity 5: You have recently purchased a shop that you want to make into a restaurant. There are no healthy takeaway restaurants in your area so you decide this will be a winning business. Design a balanced menu for a Healthy Choices Takeaway Restaurant. The menu will have a selection of main courses, deserts and drinks that considers a balance of foods from the pyramid. Some customers that visit are also likely to be vegetarian. You may choose to design your menu as a leaflet on the computer. Collect a few examples from local restaurants. Things your leaflet will need; Restaurant Name and Logo Menu Items; name and details ie. Qatar cocktail date syrup, mineral water and crushed ice. Prices $$ 17
Key Terms: Balanced diet Bread and cereal group Fruit and Vegetable group Meat group Fat group Dairy group pyramid Key Ideas: A balanced diet provides proper amounts of all the nutrients. pyramid includes the 5 food groups; bread and cereals, meat, fruit and vegetables, fats and dairy. A food pyramid helps to make choices for a healthy diet. Key Questions: Fill in the blanks using the word bank. balanced fats meat breads and cereal protein sugar dairy fruit and vegetables A healthy diet is.. The food pyramid is divided into 5 groups;,,., and. Nuts and beans are part of the meat group because they are high in Match the vitamin or mineral to what it is needed for: Vitamin/ mineral Function 1. Iron Helps you to see in dim light. 2. Vitamin A For healthy gums and skin 3. Calcium Makes red blood cells 4. Vitamin C For strong bones and teeth 18
5.7.6 Requirements for different lifestyles Planning a balanced diet considers two important things: 1. How old you are. 2. How active you are. A growing body needs a lot of protein to help with the growing process, where an older person who has finished growing doesn t. An active person like a builder or athlete needs a lot of energy, where an office worker does not. 19
Project: Choose a person from a particular profession or lifestyle (ie. office worker, student, athlete). Imagine you are the nutritionist for this person. Your job is to research a healthy balanced diet and exercise plan for this person to stay fit and healthy. Present your study and report as a role play/ interview, PowerPoint or letter of recommendation. If our energy intake is greater than our energy output, then our body stores the extra as fat. If we continue to have a higher intake than output we run the risk of becoming overweight or obese. What are some ways to avoid becoming overweight? Eat less high-energy foods (lower your energy intake) Increase exercise (increase your energy output) 20
Key question: Grade 5 students carried out a survey in their class to find out how often the students eat fruit. How much fruit Number of students 3 or 4 pieces of fruit a day 8 1 or 2 pieces of fruit a day 16 1 or 2 pieces of fruit a week 5 Less than 1 piece of fruit a week 1 a. How many students eat one or more pieces of fruit a day? b. How many students are eating the recommended intake of fruit per day?... c. Give two reasons why it is important to eat fruit in a balanced diet. 1. 2. d. Why is this advice important? 21