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Chapter 15 Section 1: Food and energy

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1 Chapter 15 Section 1: Food and energy
Key concepts: Why does your body need food? How do the six nutrients needed by the body help carry out essential processes? How can food pyramids and food labels help you have a healthy diet? Key terms: nutrient, calorie, carbohydrate, glucose, fat, protein, amino acid, vitamin, mineral, percent daily value, dietary reference intakes

2 Why you need food Food provides your body with materials for growing and for repairing tissues. Food also provides energy for everything you do.

3 Nutrients and energy Nutrients – substances in food that provide the raw materials and energy the body needs Energy – Calorie – the amount of energy needed to riase the temperature of one gram of water by one degree Celsius Most foods contain thousands of calories 1 Calorie (capital C) is equal to 1 kilocalorie The more Calories, the more energy

4 Carbohydrates Composed of carbon, hydrogen, oxygen
According to nutritionists, 45 to 65% of your diet Major source of energy and stuff to make cells Simple – known as sugars. E.g. glucose Complex – many sugars linked together in a chain. E.g. starch, fiber Starch is digestible and broken down, fiber is not

5 Fats Fats – energy containing nutrients (like carbohydrates) also made of carbon, oxygen, and hydrogen Contain more than twice the amount of energy than carbohydrates One gram of fat is 9 Calories of energy Fats form part of the cell membrane and protect and support your internal organs

6 Kinds of fats Saturated or unsaturated
Unsaturated – usually liquid at room temp Saturated – usually solid at room temp Trans fats – made by adding hydrogen to vegetable oils

7 Kinds of fats continued
Cholesterol – waxy, fatlike substance found only in animal products Your liver makes it, so you don’t need to eat more Nutritionists recommend no more than 30% of your diet be fat

8 Proteins Nutrients that contain nitrogen as well as carbon, hydrogen, and oxygen Needed for tissue growth and repair, play an important part in chemical reactions within cells Need about 10-30% of your diet to be protein

9 Proteins continued Amino acids – proteins are made up of small units called amino acids, linked together to form large protein molecules Your body makes about half the amino acids it needs, the others, called essential amino acids, have to come from the food you eat

10 Proteins continued Complete proteins – contain all essential amino acids (meat and eggs) Incomplete proteins – missing one or more essential amino acids (beans, grains, nuts)

11 Vitamins and minerals Do not provide energy or raw materials
Vitamins – helper molecules E.g. vitamin K – helps blood clot Fat soluble or water soluble Stored in fat – A, D, E, K Water soluble are not stored in the body – C Importance – vitamins keep your body healthy and working properly

12 Minerals Not made by living things
Present in soil and absorbed by plants E.g. calcium

13 Water Water is the most important nutrient
The body’s vital processes cannot take place without water All cells in your body are composed mostly of water Under normal conditions, you take in about 2 liters of water per day

14 Guidelines for a healthy diet
USDA guidelines based on sex, age, physical activity Food labels allow you to evaluate a single food as well as compare value of two separate foods Serving size Calories Percent Daily Value – how much of the nutrient needed per day is in the food Ingredients

15 Dietary Reference Intakes
DRI – guidelines that show the amounts of nutrients needed every day

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