Upload
vedpal-yadav
View
33
Download
2
Embed Size (px)
Citation preview
Good nutrition?
Food that:
1. Meets your physical
needs for energy
and nutrients
2. Maintains or
improves your
energy balance
3. Is enjoyable
Calorie:
Kilocalorie (kcal), the amount of heat
necessary to raise 1 kg of water 1 degree
centigrade
Caloric Density:
The relative number of calories per unit of
weight
Food: Our Energy Source
Nutrient Density
The relative amount of vitamins and
minerals a food provides relative to its
caloric content
Empty Calories
Derived from foods which are high in fat
and/or sugar content but lack significant
amounts of vitamins and minerals
LOW NUTRIENT DENSITY
HIGH CALORIC DENSITY
Food: Our Energy Source
Nutrients for a Healthy Body
Substances the body requires for energy, and for structural and regulatory purposes
Macronutrients:
water Micronutrients:
carbohydrates vitaminsfats mineralsprotein
Nutrients:
Water
Accounts for 50-60% of total
body weight
Involved in transport, hydration
reactions, thermoregulation
Intake ensures hydration
Normal daily H2O loss = 2
to 2.5 quarts
Soft drinks, beer, coffee cause
diuresis
Hydration During Exercise
• As exercise intensity increases, so does water loss due to sweat
Water loss due to sweat during exercise in hot weather can reach 2.8 liters/hour
• At the same time, electrolytes (Cl-, Mg++, K+, and Na+) are lost in the sweat
Hydration During Exercise
• Proper hydration
Maintains lower heart rate during exercise
Maintains lower body temperature during exercise
Results in lower percieved exertion during exercise
Hydration
• Proper hydration for exercise lasting:
< 1 hr, drink 500-1000 ml water containing 30-50gm CHO
1-3 hr, drink 800-1600ml water + electrolytes and 6% CHO
>3 hr, drink 500-1000ml water + electrolytes and 6-8% CHO
Carbohydrates
Simple carbohydrates
Sugars (table sugar, fruit sugar)
Complex carbohydrates
Fiber (Grains, fruit, vegetables,
legumes)
Starch (Grains, pasta, bread,
potatoes, legumes)
Essential for general metabolism,
primary fuel source of the brain
Fiber
•Soluble•Barley, oats, fruits, legumes, sweet &
white potatoes
•Positive effect on blood cholesterol levels
•May lower heart disease risk
•Delay emptying of the stomach
•Insoluble•Vegetables, whole wheat, wheat bran,
and cereals
•“Drano” effect
•Protective for colon cancer
Dietary goal
• 55-60% of total calories
Typical American diet
• 40-45% of total calories
Eat 5-9 servings fruits & veggies per day, and 6-11 servings breads & cereals
Only4
caloriesper
gram!
Carbohydrates, Cont.
A Little Exercise in Nutrition
• Total dietary intake of 2400 calories
• Goal is 60% carbohydrates
• Out of 2400, how many calories
should come from carbohydrates?
• How many grams of Carbohydrates
are required?
The answer….
• 2400 X 0.60 = 1440 calories
• There are 4 calories per gram
1440 cal/4 grams per cal = 360 grams
1 cup of pasta = 40 grams
Fats (lipids)
Triglycerides
•Major dietary form
of fat
Polyunsaturated
Saturated
Monounsaturated
Fatty acids
Saturated - no double
bonds
Monounsaturated
(MUFA) - one double
bond
Polyunsaturated
(PUFA) - more than
one double bond
Concentrated Energy!
Fats (lipids), Cont.
Benefits of Fats
• Fuel source: efficient form of energy
storage
• Omega-3 fatty acids (fish oil):
polyunsaturated fatty acids that are
protective
• Essential for: cell membranes, steroid
hormones, absorption of some vitamins
• Provide food with: flavor, tenderness,
aroma and palatability
Fats (lipids), Cont.
FAT FACTS
• Trans fatty acids: heart disease risk
Formed from the partial hydrogenation
of vegetable oils
• increase bad cholesterol (LDL)
• decrease good cholesterol (HDL)
• Too little fat in the diet: may lead to
vitamin deficiency, impaired hormone
production
• Too much fat in the diet: leads to
body fat accumulation; obesity
CIS
TRANS
Fats (lipids), Cont.
Dietary goals
• 30% of total calories
• 10% of fat from saturated and trans
fatty-acid sources combined
Typical American diet
• ~35-40% of total calories
from fat
Major sources: red meat, fried foods,
dairy (cheese, whole milk, butter), oils...
9calories
per gram!
Fats (lipids), Cont.
Cholesterol
• Form of dietary lipid, also synthesized by
our bodies
• Structural component of cell membranes
• Precursor to steroid hormones
• Excess cholesterol contributes to heart
disease
Sources: found only in animal products
eg. meat, milk, eggs, liver, shellfish
Blood Cholesterol Levels
Desired Border High
Total C 200 200-239 240
LDL-C 130 130-159 160
HDL-C 40 60*
(women >50)
TG 200 200-399 400-1000
1000 life threatening
A Little Exercise in Nutrition
• Total dietary intake of 2400
calories
• Goal is 25% fat
• Out of 2400, how many calories
should come from fat?
• How many grams of fat are
required?
The answer…
• 2400 X 0.25 = 600 calories
• There are 9 calories per gram
600 cal/9 cal per gram = 67 gramsReese’s Peanut Butter Cup (2) = 14 g
Recap:
• 1440 calories; 360 grams of carbs
• 600 calories; 67 grams of fat
Protein
• Composed of 20 different amino acids
9 are essentialFunctions
1. Structural: component of cells (body
tissues: muscles, bones, blood, hair)
2. Regulatory: enzymes; regulate metabolic
reactions, immune function, fluid and electrolyte
balance, acid/base balance
3. Hormones: eg. insulin
4. Energy: used to make ATP, but at a high
cost to the body
Protein, Cont.
Stored Kcals in Muscle:ATP 1-2
Phosphocreatine 4-5
Glycogen 1500-1800
Triglycerides 2500-2800
Structural Protein 25,000-30,000
Protein, Cont.
Dietary goal: 12-15%
• Animal sources contain complete proteins
• Eating complementary plant proteins
provide all nine essential amino acids
•Body can not make an incomplete protein
Sources: grains, milk, fish, meat,
beans, peas, peanuts, egg whites
Nonfat
milk
Only4 caloriesper gram!
Complementary
proteins:
Protein, Cont.
legumes (peanuts, beans, lentils, peas) +
grains (wheat, rice, corn)
•Peanut butter sandwich
•Bean & rice burrito
•Hummus (garbanzo beans + sesame seeds)
Protein Requirements for Exercise
• RDA for Protein 0.8 gm/kg/day for a sedentary population
• Light to moderate exercise:
0.8 gm/kg/day
• High-intensity endurance training:
1.2-1.4 gm/kg/day
• Initial stages strength training:
1.4-1.6 gm/kg/day
Protein Requirements
• Higher requirements for protein due to increased rate of oxidation of amino acids during exercise
• Easily attained by consumption of 12% of kcals protein per day
70 kg individual
~2900Kcal/day (348 kcal protein)
4 kcal/gm87gm protein
87gm/70kg 1.2 gm/kg/day
• Far exceeds the RDA of 0.8 gm/kg/day
A Little Exercise in Nutrition
• Total dietary intake of 2400 calories
• Goal is 15% protein
• Out of 2400, how many calories
should come from protein?
• How many grams of protein are
required?
The answer...
• 2400 X .15 = 360 calories
• There are 4 calories per gram
360 cal/4 cal per gram = 90 grams
Recap:
• 1440 calories; 360 grams of carbos
• 600 calories; 67 grams of fat
• 360 calories; 90 grams of protein
Vitamins
Organic molecules that are necessary
cofactors for normal growth and
metabolism
Functions1. Regulate cellular reactions
2. Structure & synthesis of body
tissues
Fat-soluble vitamins: A, D, E, K
Water-soluble vitamins: B complex, C
Vitamins, Cont.• Vitamins A, C, E are antioxidants. Prevent free
radicals from damaging tissues; as in cancer, diabetes
and CHD.
• Vitamin A (beta-carotene): colorful fruits and
vegetables (carrots, sweet potatoes, mangoes,
apricots)
• Vitamin C: RDA: 75 mg women, 90 mg men, 100 mg
for smokers (citrus fruits, broccoli, leafy vegetables)
• Linus Pauling Inst.: 200 mg
• 8 oz orange juice=100 mg
• Vitamin E: RDA: 15 mg
• Linus Pauling Inst.-200mg, grain oils, wheat germ,
nuts, seeds, liver and SUPPLEMENTS
Vitamins, Cont.
• The B vitamins: generally involved in
energy metabolism
B-12: animal-derived foods (dairy,eggs),
vegetarians may need fortified foods
• Vitamin D: necessary to help calcium
deposit in bones
• Folic Acid (B vitamin): coenzyme;
important in DNA synthesis
Deficiency associated with birth defects and
heart disease
Fortification of flour
Minerals
Functions1. Structural: bone, teeth,
connective tissue, enzymes,
hemoglobin
2. Maintain water balance, nerve
function, enzyme activity
Important minerals
•calcium, iron, sodium
Calcium
• Osteoporosis = weak bones
• Adequate calcium intake helps maximize
bone density in youth
RDA: 1200 mg/day (ages 19-24)
800 mg/day (over 25)
1500 mg/day for women
Sources: dairy products, dark green leafy
vegetables, calcium fortified foods
Nonfat
milk
Iron
• Essential component of hemoglobin,
mitochondria
• Anemia results from low iron intake
• Women need more than men (10 mg)
(15 mg)
Sources: meat, fish, eggs, legumes,
whole grains, enriched cereals
Iron
• Iron deficiency is the most common nutrient deficiency in exercise
• Causes
inadequate intake
loss in sweat, urine and feces
hemolysis
impaired absorption in athletes
Sodium
• Electrolyte
• Assists in transmission of nerve impulses
• Assists in muscle contraction
• Excessive intake can contribute to
hypertension
• Americans get too much!
Recommendation: 2400-3000 mg/day
The Food Guide Pyramid
Meat, poultry, fish, dry beans, eggs,
and nuts
2 - 3 servings
Fruit
2 - 4 servings
Milk, yogurt, and cheese
2 - 3 servings
Vegetables
3 - 5 servings
Fats, oils, & sweets
use sparingly
Bread, cereal, rice, and pasta
6 - 11 servings
Vegetarian Food Guide
Pyramid
Whole Grains Legumes
VegetablesFruits
Nuts and Seeds
Vegetable Oils
Dairy Eggs
Sweets
Optional
A reliable source of vit. B12 should be included if no eggs or dairy are consumed.
Interpreting Food Labels
• New labels must contain
certain information
• Serving sizes are more
realistic - be sure to
check closely
• “fat free” means < 0.5 g
fat/serving
• “low fat” means < 3 g
fat/serving
Calculating Macronutrients
Calories from fat:6g x 9 kcal/g=54 kcal
54 kcal/140kcal=39%
Calories from Carbos:
19g x 4 kcal/g=76 kcal
76 kcal/140kcal=54%
Calories from Protein:2g x 4 kcal/g=8 kcal
8 kcal/140kcal= 6%
Next Time
• In Lecture
Body Composition and Weight
Management - chapter 8
Course Evaluations