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Chapter 6 : The Human Organism and the Importance of Nutrition. Live, eat and Be Healthy!. Definitions. Nutrition The science of food and how the body uses it in health and disease Food Any substance that is ingested and sustains life. Nutrient
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Chapter 6 : The Human Organism and the Importance of Nutrition Live, eat and Be Healthy!
Definitions Nutrition The science of food and how the body uses it in health and disease Food Any substance that is ingested and sustains life. Nutrient A substance found in food that is used by the body to meet important needs
Turn to page 160 in your text book and make a quick note as to which systems are involved in the process of nutrition.
6 Main types of nutrients: • Proteins • Carbohydrates • Fats • Water • Vitamins • minerals
Energy Value Bodies must balance energy they gain from food and drink with the energy they expend carrying out our daily activities.
Energy Requirements • Amount of energy required per individual depends on a variety of factors including: • Age • Sex • Weight • Level of physical activity • Overall state of health
Daily Requirements for you Teenage adolescent Girls: Between 1800 Cal ( 7200 kJ) and 2400 Cal (9600kJ) Teenage adolescent boys: Between 2200 Cal ( 8800 kJ) and 3200 Cal (12800kJ)
Measurement Joule (J): measurement unit for energy adopted by the International System of Units Dietary calorie ( Cal): more common term 1Cal= 4000J or 4 kJ
Energy Intake The following numbers indicate how much energy is produced per gram metabolized by the body • Carbohydrates = 4 kcal/g • Protein = 4 kcal/g • Fat = 9 kcal/g
Canada’s Food Guide • The rainbow in Canada’s food guide will help you choose foods that will supply you with the right amount of nutrients your body requires • When looking at Canada’s food guide each colour represents a different group • Yellow= grains • Green= fruits and vegetables • Blue=milk and alternatives • Red=meat and alternatives
Why? • Good Nutrition is important for at least 2 reasons: • 1) It provides the energy required to carry out the many metabolic activities that our bodies require. • 2) It provides us with the essential raw materials that we need as building blocks but that our bodies are unable to manufacture for themselves.
Grains: Recommended # of servings/day: • 6 for females • 7 males Make them count! • Make at least half of your grain products whole grain each day. • Choose grain products that are lower in fat, sugar, or salt.
Milk and Alternatives: Recommended # of servings/day: • 3-4 for both males and females Make them count! • Drink skim, 1% or 2% milk each day. • Select lower fat milk alternatives: compare the nutrition facts on yogurts and cheeses to make wise choices.
Fruits and Vegetables: Recommended # of servings/day: • 7 for females • 8 for males Make them count! • Eat at least one dark green and one orange vegetable every day. • Choose vegetables and fruit prepared with little or no added fat, sugar or salt. • Have vegetables and fruit more often than juice.
Meat and Alternatives Recommended # of servings/day: • 2 for females • 3 for males Make them count: • Have meat alternatives such as beans, lentils, and tofu often. • Eat at least 2 food guide servings of fish each week. • Select lean meat and alternatives prepared with little or no added milk or salt.
Examples of a serving: Grains: 1 slice of bread;1/2 a bagel, pita or tortilla; 30 g of cold cereal or ¼ cup of hot cereal;1/2 cup of cooked pasta, rice or couscous. Fruit and Vegetables: ½ a cup of frozen or canned veggies; ½ a cup of 100% juice; 1 fruit.
Examples of a serving: Milk and Alternatives: 1 cup of milk;1 cup of fortified soy beverage; ¾ cup yogurt; 1.5 oz cheese. Meat and Alternatives: 2tbsp peanut butter; ¼ cup shelled nuts/seeds ¾ cup cooked legumes; cooked fish,1/2 cup shellfish, poultry and lean meat.
Nutrition Facts: Reading a label • Example: • Note serving size • % daily value is based on a 2000 calorie diet
% Daily Value (DV) • The % DV helps you see if a specific amount of food has a little or a lot of a nutrient. • 5% DV or less is a little of the nutrient } This applies to all nutrients • 15% DV or more is a lot of the nutrient • Note that the Food and Drug Administration (FDA) has not set a Daily Value for trans fat, and health experts recommend avoiding trans fat to lower your risk of cardiovascular disease. Similarly, there is no established Daily Value for sugar.
Recommended Macronutrient Consumption Protein 10-35% Fat 20-35% Carbohydrate 45-65%
Low Fat • Low fat foods often contain a fair amount of sugar to maintain flavour • People don’t necessarily consume less energy this determines whether you gain weight or not • What can sugar be converted to?
Trans fat • Similar to saturated fats • Increase concentration of LDL • Reduces concentration of HDL
Vegetarian Diet Vegetarian Diet • Attempt to avoid meat or fish on moral or other grounds, although most consume dairy and eggs. Vegans • Vegetarians who in addition to meat and fish do not consume dairy or eggs.
Issues with Herbivores Issues • Restrictive vegetarian diets may limit a persons protein intake. • They too have Iron, and B12 deficiencies Solutions • To increase protein, eat a diet rich in whole grains, beans and vegetables . • To increase iron intake, eat dried beans, brewer’s yeast , spinach and dried fruits. • To increase B12, eat fortified cereals, sunflower margarine and fermented soya products.
Dietary Supplements • Eating a well balanced diet should provide the recommended amount of vitamins and nutrients • Supplements should only be required/used when: • Ill • Planning to have children • Suffering from digestive problems • Following a special diet • Recovering from an injury • Consuming more than the recommended levels can in fact cause harm
Why Exercise? • Raises your metabolism, burns calories more muscle = more calories burnt at rest • Strengthens your bones (important for females) • Increases muscular endurance • Helps you avoid injuries • Increases confidence and self-esteem • Improves coordination and balance • Decreases risk of cardiovascular disease • Improves mood
Body Mass Index • The body mass index (BMI) is a person's weight in kilograms (kg) divided by their height in meters (m) squared. • The National Institute of Health defines normal weight, overweight, and obesity according to the BMI rather than the traditional height/weight charts.
Issues with BMI • Men and Women are different, so why should adult men and women have exactly the same BMI? • Short adult women have higher BMI than taller women. • Race/ethnicity and nationality affect body composition and BMI. • Muscular people, athletes and bodybuilders particularly, have high BMI values, but are not fat.
Weight Management • Depends largely on 2 factors:# calories absorbed through food intake and the number expended through body metabolism and physical activity Maintain a healthy weight by: • A diet high in nutrients and low in calories • Reduce caloric intake • Reduce fat intake • Increase physical activity
Obesity in Canada • Increase More dramatic in children • Major causes: poor diet and inactivity • A man’s life expectancy is reduced by 20 yrs if obese when 20 for women it’s reduced by 8 yrs • Food consumption must be adapted to activity levels, body composition, and changing hormone levels (generally just with age)
Underweight • BMI < 18.5 • 1998-1999 – 1 in 10 Canadians • Women are 3 times more likely • Women are more likely to try and lose weight can start as early as age 9
Underweight Signs of Disordered Eating: • Preoccupation with food and weight • Repeatedly expressed concerns about being fat • Increasing criticism of one’s body • Frequently eating alone • Use of laxatives • Trips to the bathroom during/following meals • Continuous drinking of diet soda or water • Compulsive, excessive exercise • Complaints of always being cold
Dehydration • Heat-regulating centre: hypothalamus 1) Reflex dilation of skin: • Forces blood to flow and transfer heat to skin 2) Sweating Reflex: • Sends excess fluid to the surface to evaporate • These cool and dehydrate the body Other ways to lose water: • Urine, feces, & breathing
Fluid Replacement Before Exercise: • Start well hydrated • 2-3 cups of fluid containing carbohydrates 2-3 hours before • 1 cup 10-20 minutes before During Exercise: • If > 50 minutes – a sports beverage with carbs • Carbohydrate concentration of 6-8% • 6% electrolyte-carbohydrate solution • Drink at least one ½ cup fluid after each 10 mins
Electrolytes • Medical/scientific term for salt • Main salts required by the cells of a body are : Na+ and Cl- • Cells need these to maintain voltages across membranes and carry impulses-nerve muscle contraction etc. • Certain concentration needed to prevent dehydration • Gatorade, poweraid etc.