Energy
1. A car needs energy to move. That energy comes from gas in the tank. The energy we need to do all the activity we do comes from our food.
2. To use this energy, our cells convert the energy in food to a chemical called ATP using the process of cellular respiration.
3. The energy stored in food is measured in dietary Calories (with a capital C).
4. Different types of foods contain different amounts of energy
a. Fats contain about 9 Calories per gram
b. Carbohydrates and proteins each contain about 4 Calories per gram
5. Your energy needs depend on your sex and your lifestyle.
a. The energy needs of an average teenager are about 2200 Calories per day for females and about 2800 Calories per day for males.
b. If you are active you need more energy than the average.
Nutrients
1. Nutrients are substances in food that supply the energy and raw materials your body needs for growth, maintenance, and repair.
2. We can get energy from any food we eat but it is important to eat a variety of foods because food also supplies the raw materials to build and repair body tissue.
3. Food contains at least 45 things that cells need but cannot make themselves.
Water
1. Water is the most important nutrient because cells are made mostly of water.
2. Also, cells need water because most of the chemical reactions in cells take place in water.
3. Water must be constantly replaced because it is lost by sweating and as water vapor when you breathe or talk.
4. Drinking plenty of water is one of the best things you can do to keep your body healthy.
5. We get water from drinking water and other beverages as well as the food we eat.
Carbohydrates
1. Carbohydrates are the main source of energy for cells.
2. Contrary to popular belief, they are not “bad” for you.
3. The two types of carbohydrates are simple and complex.
4. Simple carbohydrates are sugars like glucose and sucrose. They are found in anything that tastes sweet.
5. Simple sugars provide quick energy for cells.
6. Complex carbohydrates are found in grains, potatoes, and vegetables. We usually call these starches and in our diet they would come mostly from rice, potatoes, beans, bread and pasta.
7. Complex carbohydrates provide you with a slow, steady source of energy.
8. Carbohydrates that are not needed for energy are stored in the liver and skeletal muscle.
9. Plants contain the complex carbohydrate cellulose, also called fiber. Although we cannot digest cellulose it is important in our diet because it helps to fill the colon and move wastes through the digestive tract.
Fats
1. Fats (or lipids) are needed by the body to build cell membranes and certain hormones as well as for the proper functioning of the nervous system.
2. Contrary to popular belief, fats are not “bad” for you but are an important part of the diet.
3. The two types of fat are saturated and unsaturated.
4. Saturated fats come from animals and are usually solid at room temperature.
5. Unsaturated fats come from plants and are usually liquid at room temperature.
6. Fats contain double the energy of an equal amount of carbohydrates or proteins.
7. When you eat more fat than you need for energy, the excess is stored as fat.
8. This energy is used after the energy from carbohydrates has been used.
Proteins
1. Cell parts that are made of protein are repaired and replaced from the raw materials (amino acids) we get from eating proteins.
2. Humans can make 12 of the 20 different amino acids we need. The others (called essential amino acids) have to be present in our diet to avoid shortages.
3. The main sources of protein in our diet are meat, fish, beans, eggs, and milk.
4. Animal proteins are called complete because they contain all the amino acids we can’t make. Most plant proteins are called incomplete.
Vitamins and Minerals
1. Vitamins are organic molecules that are needed for the body to function properly.
2. Only two vitamins (A and K) can be made by the body. The others must be obtained in our diet.
3. Vitamin D is made by exposure to UV radiation and vitamin K is made by bacteria in the large intestine.
4. Fat-soluble vitamins can be stored in fatty tissue in the body. Because of this, the body can store a small amount of these vitamins.
5. Water-soluble vitamins dissolve in water and cannot be stored in the body. These need to be eaten every day.
6. It is important to note that taking vitamin supplements can be dangerous because some vitamins (like A, D, E, and K) can be toxic in large amounts.
7. Minerals are inorganic nutrients that are needed, usually in small amounts.
8. Minerals are lost in sweat, urine and feces and so must be replaced by including them in the diet.
Healthy Diet
1. The Canada Food Guide provides information about what kinds and what amounts of food we should eat each day.
2. Research has shown that a diet based in the food guide results in a lower risk of heart disease and cancer.
3. Many diseases have been linked to excess weight so weight control is an important part of overall health.
4. The number of calories you eat each day and the number you burn act together to determine whether you gain or lose weight.
5. When you eat more than you burn, you gain weight. When you burn more than you eat, you lose weight.
6. Any kind of physical activity burns calories.
7. Exercise contributes to overall health.
8. Sleep is not well understood but is also important for overall health.
Nutritional Problems
1. Serious diseases and illness can result from not eating a healthy diet.
2. An eating disorder is a serious disturbance in normal eating habits and are usually caused by emotional problems.
a. Anorexia nervosa is a refusal to eat. Sufferers believe they are overweight no matter how thin they become. It can be fatal if not treated.
b. Someone with bulimia nervosa eats plenty of food but then vomits.
3. A deficiency disorder results when a particular nutrient is missing from the diet.
4. Malnutrition is a weakened condition that results when your body is not properly nourished.