Chapter 1Chapter 1

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Chapter 1: What You Chapter 1: What You Eat and Why?Eat and Why?

What is What is Nutrition?Nutrition?

NNutrition isutrition is

““the science of food, the nutrients the science of food, the nutrients and the substances therein, their and the substances therein, their action, interaction, and balance in action, interaction, and balance in relation to health and disease, and relation to health and disease, and the process by which the organism the process by which the organism ingests, absorbs, transport, utilizes, ingests, absorbs, transport, utilizes, and excretes food substances”----and excretes food substances”----The Council on Food and Nutrition of the American The Council on Food and Nutrition of the American Medical AssociationMedical Association

Nutrients Come from FoodNutrients Come from Food

Provide energyProvide energy Provide building blocksProvide building blocks Vital for growth and Vital for growth and

maintenancemaintenance EssentialEssential

Essential NutrientEssential Nutrient

Omission leads to declineOmission leads to declineRegain normal function when Regain normal function when

restored to the dietrestored to the dietHas specific biological Has specific biological

functionfunction

Why study nutrition?Why study nutrition?

Nutrition and HealthNutrition and Health

Poor diet and sedentary lifestyle are Poor diet and sedentary lifestyle are risk factors for chronic diseases:risk factors for chronic diseases:– Disease of the heart (29% of all deaths)Disease of the heart (29% of all deaths)– Cancer (22%)Cancer (22%)– Cerebrovascular disease (~7%)Cerebrovascular disease (~7%)– Diabetes (3%)Diabetes (3%)– Accounts for ~2/3 of all deathsAccounts for ~2/3 of all deaths

Maintain optimal healthMaintain optimal health ““Affliction of Affluence”Affliction of Affluence” We are living longerWe are living longer

The Six Classes of NutrientsThe Six Classes of Nutrients

CarbohydratesCarbohydrates Lipids Lipids ProteinsProteins VitaminsVitamins MineralsMinerals WaterWater

Nutrient Functional Nutrient Functional CategoriesCategories

Provide caloriesProvide calories For growth, development, and For growth, development, and

maintenancemaintenance Regulate body processesRegulate body processes

CarbohydratesCarbohydrates

Composed of carbon, hydrogen, Composed of carbon, hydrogen, oxygenoxygen

Major source of fuel Major source of fuel Monosaccharide (glucose) Monosaccharide (glucose) Simple and complex formsSimple and complex forms Dietary fiberDietary fiber Energy yielding (~4 kcal /gm)Energy yielding (~4 kcal /gm)

LipidsLipids Composed of carbon, hydrogen, fewer Composed of carbon, hydrogen, fewer

oxygenoxygen Triglycerides Triglycerides

– Fats and oilsFats and oils Unsaturated Fatty AcidsUnsaturated Fatty Acids Saturated Fatty AcidsSaturated Fatty Acids Essential Fatty AcidsEssential Fatty Acids Energy yielding fats and oils (~9 Energy yielding fats and oils (~9

kcal /gm)kcal /gm) CholesterolCholesterol PhospholipidsPhospholipids

ProteinsProteins Composed of carbon, hydrogen, Composed of carbon, hydrogen,

oxygen, nitrogenoxygen, nitrogen Structural materialStructural material (9) Essential amino acids (9) Essential amino acids (11) Nonessential amino acids(11) Nonessential amino acids Energy yielding (~4 kcal /gm)Energy yielding (~4 kcal /gm) Excess protein intakeExcess protein intake

VitaminsVitamins

Composed of various elementsComposed of various elements Enable chemical reactionsEnable chemical reactions Fat solubleFat soluble Water solubleWater soluble Yield no energyYield no energy

MineralsMinerals

Inorganic substancesInorganic substances Function in cellular processes, nervous Function in cellular processes, nervous

system, water balance, structural system, water balance, structural systemssystems

Not destroyed during cookingNot destroyed during cooking Trace mineralsTrace minerals Major mineralsMajor minerals Electrolytes Electrolytes Yield no energyYield no energy

WaterWater Composed of hydrogen, oxygenComposed of hydrogen, oxygen Majority of our body weightMajority of our body weight Found in foodsFound in foods Yields no energyYields no energy Recommended intakeRecommended intake

– 9-13 cups/day9-13 cups/day Functions:Functions:

– Solvent, lubricant, medium for transport, Solvent, lubricant, medium for transport, chemical processes, and temperature regulatorchemical processes, and temperature regulator

PhytochemicalsPhytochemicals A chemical found in plantsA chemical found in plants

– Not considered essential nutrientsNot considered essential nutrients– Provide significant health benefitsProvide significant health benefits– Found in fruits and vegetablesFound in fruits and vegetables

CompositionComposition

Transformation of EnergyTransformation of Energy

carbohydrate PROTEIN FAT ALCOHOL(4 kcal/gm 4 kcal/gm 9 kcal/gm 7kcal/gm)

ENERGY SOURCES

Build new compounds Muscular movement

Nerve transmission Ion balance

What is a Calorie?What is a Calorie?

Measurement of energyMeasurement of energy ““The amount of heat it takes to The amount of heat it takes to

raise the temperature of 1 gram raise the temperature of 1 gram of water by 1 degree Celsius”of water by 1 degree Celsius”

1,000 calories = 1 kcal = 1(food) 1,000 calories = 1 kcal = 1(food) CalorieCalorie

Sample Calculation of a Sample Calculation of a Nutrition LabelNutrition Label

Per serving Per serving – Carbohydrate: 15g x 4 kcal/g = Carbohydrate: 15g x 4 kcal/g = 60 kcal60 kcal– PRO: 3g x 4 kcal/g = PRO: 3g x 4 kcal/g = 12 kcal12 kcal– FAT: 1g x 9 kcal/g = FAT: 1g x 9 kcal/g = 9 kcal 9 kcal– TOTAL: 81 kcal, rounded down toTOTAL: 81 kcal, rounded down to 8080

Contribution to Total kcalContribution to Total kcal

One day’s intake (1980 kcal)One day’s intake (1980 kcal) 290 gm of carbohydrate (x 4 kcal/gm)290 gm of carbohydrate (x 4 kcal/gm) 60 gm of fat (x 9 kcal/gm)60 gm of fat (x 9 kcal/gm) 70 gm of protein (x 4 kcal/gm)70 gm of protein (x 4 kcal/gm) % of kcal as carbohydrate = (290 x 4)/1980 = % of kcal as carbohydrate = (290 x 4)/1980 =

0.59 or 59%0.59 or 59% % of kcal as Fat= (60 x 9)/1980 = 0.27 or % of kcal as Fat= (60 x 9)/1980 = 0.27 or

27%27% % of kcal as PRO= (70 x 4)/1980 = 0.14 or % of kcal as PRO= (70 x 4)/1980 = 0.14 or

14%14%

The Typical American DietThe Typical American Diet

16% of kcal as proteins16% of kcal as proteins– ~66% from animal sources~66% from animal sources– 10-35% advised10-35% advised

50% of kcal as carbohydrate50% of kcal as carbohydrate– ~50% from simple sugars~50% from simple sugars– 45-65% advised45-65% advised

33% of kcal as fat33% of kcal as fat– ~60 % from animal fats~60 % from animal fats– 20-35% advised20-35% advised

Assessing Our DietsAssessing Our Diets

National Health and Nutrition National Health and Nutrition Examination Survey (NHANES) [US Examination Survey (NHANES) [US Dept. of Health & Human Services]Dept. of Health & Human Services]

Improving Our DietsImproving Our Diets

Monitor energy intakeMonitor energy intake Salt (sodium) in moderationSalt (sodium) in moderation Alcohol in moderationAlcohol in moderation Fat in moderationFat in moderation Adequate fluidsAdequate fluids Eat 5-A-DayEat 5-A-Day Use supplements wisely, if at allUse supplements wisely, if at all Mealtime is a social timeMealtime is a social time

Healthy People 2010Healthy People 2010www.health.gov/healthypeoplwww.health.gov/healthypeoplee

Promote healthy lifestyle Promote healthy lifestyle Reduce preventable deaths and Reduce preventable deaths and

diseasesdiseases Reduce obesity in adults and childrenReduce obesity in adults and children Increase intake of fruits, vegetables, Increase intake of fruits, vegetables,

and whole grain productsand whole grain products Lower intake of fat, saturated fats, Lower intake of fat, saturated fats,

and sodiumand sodium Increase intake of calcium and ironIncrease intake of calcium and iron

Why Am I So Hungry?Why Am I So Hungry?

HungerHunger– Physical biological drivePhysical biological drive

AppetiteAppetite– Psychological drive Psychological drive

SatietySatiety

Regulated by the Regulated by the hypothalamushypothalamus

Feeding centerFeeding center Satiety centerSatiety center Meal size and Meal size and

compositioncomposition Macronutrients in the Macronutrients in the

bloodblood HormonesHormones

Eating Well in CollegeEating Well in College Freshman FifteenFreshman Fifteen

– Stressful situationsStressful situations– University environmentUniversity environment– Peer pressurePeer pressure– AlcoholAlcohol– Lack of ExerciseLack of Exercise