Chapter 7: Eating Right

McGraw-Hill/Irwin © 2012 McGraw-Hill Companies. All Rights Reserved.

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Why do you need to know about nutrition?

• Nutrition:– The science of certain food substances

• Important terminology– nutrition - diuretics– diet - nutrient density– nutrients - requirement– deficiencies - recommendations– over-nutrition

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Basic Principles of Nutrition

• Diet refers to food selection

• Nutrients serve three major roles:– Growth, repair and maintenance of all body

cells– Regulation of body processes– Supply of energy for cells

• Some nutrients can be made by the body– Essential nutrients must be supplied by an

individual’s diet

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• 6 major nutrients:– Carbohydrates– Fats– Protein– Water– Minerals– Vitamins

• If all necessary nutrients are not brought into the body, nutritional deficiencies may develop

Macronutrients

Micronutrients

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• Overnutrition– Eating too much food or specific nutrients– Common problem in the United States– Can lead to obesity

• Energy for the body– Energy value of food is measured in calories– Carbohydrates = 4 calories per gram– Fat = 9 calories per gram– Protein = 4 calories per gram– Alcohol = 7 calories per gram

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MACRONUTRIENTS

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Carbohydrates (CHO)

• Provides body with energy– While body will also run on fat and protein,

CHO is preferred source of energy

• 55% of total caloric intake should be accounted for by CHO

• Classified into simple (sugars) or complex (starch, glycogen, fiber)

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• Sugars:– Simple carbohydrates that occur as single or double-

sugar chemical units– Glucose (blood sugar) is needed to fuel cells– Must be careful not to consume too much sugar in diet

(empty calories)

• Starches:– Complex carbohydrates (long glucose chains)– Found in cereal grains, potatoes, and beans– Glycogen is broken down and released as glucose in

the body when necessary

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• Fiber:– Helps individuals avoid constipation

• Low fiber diets are blamed for intestinal problems

– Also may be helpful in lowering blood cholesterol levels, which are a major risk factor for cardiovascular disease

– Most forms are complex carbohydrates– Sources

• Dietary and functional fiber• Fruits, vegetables, whole grain breads and cereals, nuts,

beans, and peas

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Fats

• Extremely important in one’s diet

• Extra calories consumed as carbohydrates, proteins and fats can all be converted into triglycerides and stored for future use

• Stored fat serves multiple functions:– Serves to cushion organs– Provides energy to muscles

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• Saturated vs. unsaturated fats:– Saturated fats are derived primarily from

animal products• Found in meat (pork, chicken, beef), eggs, and

dairy products• Also can be found in coconut and palm oils• Increase blood cholesterol levels

– Unsaturated fats are liquid at room temperature

• Contain omega-3 and omega-6 fatty acids• Found in vegetable and fish oils• Tend to be better for an individual

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• Cholesterol:– Fat-related substance found in animal foods

– Believed to be responsible for creating blocked arteries

– If enough is not consumed, your body will produce it naturally

• Trans fatty acids:– Resemble saturated fatty acids

– Results in hardening oils

– Will boost levels of bad cholesterol

– No safe level as there is no health benefit

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• Fat intake:– Total fat consumption vs. consuming specific

fats– Makes up 40% of total calories consumed by

Americans• Recommended levels (25-30%)

– Cholesterol recommended levels = 300mg– Recommendations on reducing fat intake may

be partially responsible for reducing cardiovascular deaths

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Protein

• Required for growth, repair and maintenance of cells

• Major constituent of all structures and organs of the body

• Not a primary source of energy

• Greater need for protein during periods of growth, breast feeding, active body-building

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• Recommendations:– 0.8 grams/kg of body weight– Should be approx. 12-15% of caloric intake

• Proteins are composed of smaller sub-units (amino acids)– 20 amino acids in the body, 9 must be supplied

by diet– All are necessary for growth– Primarily found in animal products, some in

plants

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MICRONUTRIENTS

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Water

• Most essential nutrient:

– 60% of the adult body is water

• Required for energy production, maintaining cell function, and cooling of the body

• Body requires 2.5 liters (10 glasses) daily

• Sports drinks:– Allows for hydration, electrolyte and energy

replacement– Better for re-hydrating, water itself can shut off thirst

response and turn on kidney function prematurely

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Vitamins

• Vitamins (13) serve as regulators in many body processes

• Help to regulate metabolism and energy production, not a source of energy

• Elderly, alcoholics, and those that restrict food intake severely are susceptible to vitamin deficiencies

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• Fat soluble vitamins:– Vitamins A, D, E, K– Found in fatty portion of foods and oils– Not easily eliminated from the body– Stored in liver and body fat – can make them

potentially toxic

• Water soluble vitamins:– Vitamin C, B-complex vitamins– Help to regulate metabolism but cannot be stored– Each serves a series of roles

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• Antioxidants:– May prevent premature aging, cancers, heart

disease and other health problems– Helps protect cells from free radicals– Includes vitamins A, C, E– Found in a number of dark green, deep yellow

and orange fruits and vegetables

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Minerals• More than 20 minerals have essential roles in the

body, including: – Calcium

– Iron

• Many are stored in liver and bones• Required for a number of things:

– Bones

– Teeth

– Activating enzymes

– Energy production

– Maintaining water balance

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Production of Energy• Occurs when cells break down chemical

units of glucose and fats or amino acids– Must burn energy-supplying nutrients– Results in heat production and usable energy

for cells to work– Proportions of nutrients burned depend on

type, duration and intensity of exercise

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Nutrient Dense vs. Junk Foods

• Nutrient dense– Foods containing considerable amounts of

vitamins, minerals, and proteins in relation to their caloric content

• Junk foods– Contain too many calories (through sugar and

fats) in relation to the proportion of vitamins and minerals

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Nutrient Requirements and Recommendations

• Requirement:– Amount of a nutrient that is needed to prevent nutrient deficiency

disease

• Recommendations:– Takes into account the amount necessary to avoid deficiency

• US Recommended Dietary Allowances (USRDA):– Allows for comparison of the nutrition of food products

• Dietary Reference Index (DRI)• Upper intake levels (UL) • Estimated average requirement (EAR) • Adequate intake (AI)

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Dietary Guidelines• Nutrition and health recommendations for healthy

children and adults• In 2010, more emphasis was placed on helping

consumers build healthier diets– Emphasizes fruits, vegetables, whole grains, fat-free or

low-fat milk, lean meats/poultry, fish, beans, eggs and nuts

• Actionable messages include: – Balance calories– Foods to increase– Foods to decrease

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MyPlate• 2011 campaign that focuses on healthier

eating habits– Helps consumers build a healthy “plate”

based around fruit, vegetables, grains, protein, and dairy

– Identifies percentages of different types of food to eat in a given meal

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Reading Labels

• Lists total calories and calories from fat per serving

• Information that is based on percent daily values

• Provides information on specific nutrients relative to % daily values

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What is the role of nutrition in physical activity?

• Physically active people believe that certain nutrients can help in achieving fitness goals/competitive edge

• Sometimes certain foods will be avoided by athletes

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Nutritional Supplements• Little evidence that vitamin, mineral or protein

supplementation enhances physical performance:– Be a careful consumer– Generic vitamins and minerals are just as effective– Don’t be misled by labels– Consuming more than 150% of the recommended

levels may be unhealthy– Supplements should not be a substitute for food

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Sugar• Ingesting large quantities of sugar prior to

activity causes increased glucose in the blood

• Release of insulin stimulated, allowing cells to utilize free-circulating glucose, sparing blood glucose

• Positive effect on performance

• However, some athletes are sensitive to high CHO feedings and have problems with increased levels of insulin

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Caffeine

• Central nervous system stimulant found in carbonated beverages, coffee, tea

• Increases alertness and decreases fatigue

• Too much causes nervousness, irritability, increased heart rate and headaches

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Alcohol• Provides energy for the body

• Little nutritional value

• Central nervous system depressant

• Not wise to replace water with alcohol before, during, or following activity

• Too much alcohol can damage liver and brain cells

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Herbs• Safe to ingest as natural medicines with few side

effects (occasional allergic reaction)• No federal or governmental regulations on

quality or distribution– Exercise caution with consumption

• Herbs serve as body balancers that work with functions of the body

• Uses may be general for overall strength and nutrient support or specific to a condition or ailment

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The Problem with Eating Fast Food

• 40-50% of calories consumed in fast food are fat calories

• Add the “supersize” label and the problem is compounded

• Some fast food establishments have worked to broaden their menu to include healthier options

• Nutritional information is also available for the consumer

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Pre-event Meal• Long term food consumption is more

important than immediate consumption• Purpose should be to provide competitor

with nutrients/energy and fluids for competitions– A light (300 calories) meal 2-4 hours before is

encouraged

• Avoid a full stomach and fatty foods• Preloading with water is also suggested

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Vegetarianism• Utilizes plants to form foundation of diet• Economic, philosophical, religious, cultural, or

health reasons• Diet must be carefully planned• Total vegetarian (vegan): No animal products • Lactovegetarian: Consumes plant and milk

products• Ovolactovegetarian: Consumes plant, milk, and

egg products• Semivegetarian: Does not consume red meats

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Food Safety• Must be careful both with food preparation and

consumption• Foodborne illness:

– Result of bacteria in food– Raw foods are most common source due to lack of

sterilization

• Can happen in your kitchen if food left out for 2 or more hours at room temperature

• Treatment:– Increase fluid intake; hospitalization if more serious