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  1. Calories CALORIES A calorie is a unit of energy, specifically potential energy.

  2. Food into energy As we know, our bodies obtain energy from carbohydrates, fats and proteins. We get energy from nutrients. The energy is stored in the chemical bonds. 1 gram of carbohydrate = 4 cal 1 gram of protein = 4 cal 1 gram of fat = 9 cal How much energy is there in 30 grams of carbohydrate? How much energy is there in 30 grams of fat? Why does a low fat diet help keep weight down?

  3. Nutrition Labels Foods are a compilation of these three building blocks. So if you know how many carbohydrates, fats and proteins are in any given food, you know how many calories, or how much energy, that food contains.

  4. Nutrition Labels 1 serving of goldfish has 5g of fat, 20g of carbs and 4g of proteins, totaling 140 calories Fat Calories 5g x 9 cal/g = 45 cal Carbohydrate Calories20g x 4 cal/g = 80 cal Protein Calories4g x 4 cal/g = 16 cal Total Calories45 + 80 + 16 = 141 cal

  5. Your energy needs The body uses energy all the time just to keep warm, keep the heart beating and the lungs breathing. The Basal Metabolic Rate (BMR) is the amount of energy we require just to stay alive, awake and warm. To move around, digest food and exercise, we need even more energy. This is called our working energy. Our working energy depends on how active we are. basal metabolic rate + working energy Total energy needed = This can be measured in calories (cal).

  6. Individual energy needs The amount of energy required varies from person to person. It depends on a number of factors: Age – as you grow up and your body gets larger, it requires more energy. However, after the age of about 40, your metabolism slows down and you don’t need to eat as much. Size – larger people require more energy to keep their bodies functioning and to move them around. Gender – males usually require more energy than females because they tend to be more heavily built. Lifestyle – the more activity you do, the more energy you will require.

  7. Individual energy needs per day (cal) Why do you think that, on average, adult males working in offices need fewer calories than 16 year-old males?

  8. Individual energy needs per day (cal)

  9. Energy balance When you participate in sport and other activities, you burn extra energy. The amount of energy you use will depend on: • what type of exercise you do • how long you exercise for • how hard you exercise. Here are some guidelines for the energy used in different activities:

  10. Energy balance

  11. Exam-style question • ‘Elite performers’ need to think carefully about their diets. • List four elements that should be included in a healthy diet, but do not provide the body with energy. • Explain two ways in which the dietary needs of an elite performer may differ from those of an average person. • Describe the importance of the following in maintaining health. • Fibre • Water

  12. Portion Distortion PORTION DISTORTION