chapt01 lecture nutrition

Chapter 1: What you eat and why

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

Chapter 1: What you eat and whyFactors Affecting Food ChoicesFactors Affecting Food Choices

Social needs

Psychologicalneeds

Food availability

Food marketing

Health and nutritionconcerns, knowledge,

and beliefs

Lifestyle

Routinesand

habits

Education,occupation,and income

Food cost

Food customsand

culture

Social networkof family

and friends

Food flavor, texture, and appearance

preferences

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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, relation to health and disease, and the process by which the and the process by which the organism ingests, absorbs, organism ingests, absorbs, transport, utilizes, and excretes transport, utilizes, and excretes food substances”----food substances”----The Council on Food The Council on Food and Nutrition of the American Medical Associationand Nutrition of the American Medical Association


Scientific MethodScientific Method

the careful noting and recording of natural phenomena

a procedure designed to test an idea

a tentative explanation of a single or small number of natural phenomena

a general explanation of natural phenomena

a generally observed natural phenomenon

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Gathering Empirical Gathering Empirical KnowledgeKnowledge──ObservationObservation

Some observations are simple Some observations are simple descriptions about the descriptions about the characteristics or behavior of characteristics or behavior of naturenature──qualitativequalitative..– ““The soda pop is a liquid with a The soda pop is a liquid with a

brown color and a sweet taste. brown color and a sweet taste. Bubbles are seen floating up Bubbles are seen floating up through it.through it.””

Some observations compare a Some observations compare a characteristic to a standard characteristic to a standard numerical scalenumerical scale──quantitativequantitative..– ““A 240-mL serving of soda pop A 240-mL serving of soda pop

contains 27 g of sugar.contains 27 g of sugar.””5


From Observation to UnderstandingFrom Observation to Understanding

hypothesishypothesis──a tentative a tentative interpretation or explanation for interpretation or explanation for an observationan observation– ““The sweet taste of soda pop is due The sweet taste of soda pop is due

to the presence of sugar.to the presence of sugar.”” A good hypothesis is one that can A good hypothesis is one that can

be tested to be proved wrong!be tested to be proved wrong!– falsifiablefalsifiable– One test may invalidate your One test may invalidate your

hypothesis.hypothesis.6


Testing IdeasTesting Ideas• Ideas in science are tested with Ideas in science are tested with

experimentsexperiments..• An experiment is a set of procedures An experiment is a set of procedures

that are designed to test whether an that are designed to test whether an idea about nature is valid.idea about nature is valid.

• The experiment generates The experiment generates observations that will either validate observations that will either validate or invalidate the idea.or invalidate the idea.

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From Specific to General From Specific to General ObservationsObservations

• A A scientific lawscientific law is a summary of is a summary of observations that combines all observations that combines all past observations into one past observations into one general statement.general statement.

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• Allows you to predict future observationsSo you can test the law with

experiments.


From Specific to General From Specific to General UnderstandingUnderstanding

• A A hypothesishypothesis is a potential is a potential explanation for a single or small explanation for a single or small number of observations.number of observations.

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• A theory is a general explanation for the manifestation and behavior of all nature.modelspinnacle of scientific knowledgevalidated or invalidated by

experiment and observation


• • Make an observationMake an observation– Form a hypothesis via Form a hypothesis via inductive inductive

reasoningreasoning– Conduct an experiment, collect Conduct an experiment, collect

data, make further observationsdata, make further observations– Reach a conclusionReach a conclusion– Formulate a theory Formulate a theory – ModelsModels– Repeat/statistical significanceRepeat/statistical significance– New questionsNew questions


Experiments performed in science have specific Experiments performed in science have specific elementselements

The experimental design is the well-conceived plan for a The experimental design is the well-conceived plan for a specific experiment.specific experiment.

• • ExperimentsExperiments typically have two groups.typically have two groups.–– Experimental group:Experimental group: the group manipulated during the experiment the group manipulated during the experiment–– Control groupControl group: the reference group, left unmanipulated: the reference group, left unmanipulated

Experiments collect data.Experiments collect data.– Experimental variable Experimental variable (Independent): factor of the experiment being (Independent): factor of the experiment being

tested.tested.– Response Variable Response Variable (Dependent): Result or change that occurs due to (Dependent): Result or change that occurs due to

the experimental variablethe experimental variable


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 NutrientOmission 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 Why study nutrition?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 The Six Classes of NutrientsNutrients

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, oxygenComposed of carbon, hydrogen, oxygen Major source of fuel Major source of fuel Monosaccharide (glucose) Monosaccharide (glucose) Simple and complex formsSimple and complex forms


CarbohydratesCarbohydrates


CarbohydratesCarbohydrates Dietary fiberDietary fiber Energy yielding (~4 kcal /gm)Energy yielding (~4 kcal /gm)


LipidsLipids Composed of Composed of

carbon, carbon, hydrogen, fewer hydrogen, fewer oxygenoxygen

Triglycerides Triglycerides – Fats and oilsFats and oils


LipidsLipids Unsaturated Fatty AcidsUnsaturated Fatty Acids Saturated Fatty AcidsSaturated Fatty Acids


LipidsLipids Essential Fatty AcidsEssential Fatty Acids Energy yielding fats and oils (~9 kcal /gm)Energy yielding fats and oils (~9 kcal /gm) CholesterolCholesterol PhospholipidsPhospholipids


ProteinsProteins Composed of carbon, hydrogen, oxygen, nitrogenComposed of carbon, hydrogen, oxygen, 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 Excess protein intakeintake


ProteinsProteinsChemical structure

Globularstructure


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 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 EnergyCarbohydrate Protein Fat

(4 kcal/gm 4 kcal/gm 9 kcal/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


Calorie SourcesCalorie Sources

CARBOHYDRATESCARBOHYDRATES 4kcal/g 4kcal/gPROTEINPROTEIN 4kcal/g4kcal/gFATFAT 9kcal/g9kcal/gALCOHOLALCOHOL 7kcal/g7kcal/g


Sample Calculation of a Nutrition LabelSample Calculation of a Nutrition 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


Calculating PercentagesCalculating Percentages

6% of 45 0.06 X 45= 2.76% of 45 0.06 X 45= 2.7 3 is what percent of 993 is what percent of 99

3/99=3.03%3/99=3.03%


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 Dept. of Health & Human Services]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/healthypeople

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


What can you gain?What can you gain?


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 Macronutrients in

the bloodthe blood HormonesHormones


Eating Well in Eating Well in CollegeCollege

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


Weight control and Weight control and College lifeCollege life

Eat breakfastEat breakfast Plan ahead balanced mealsPlan ahead balanced meals WaterWater Low-calorie, nutritious snacksLow-calorie, nutritious snacks Eat and work out with friendsEat and work out with friends


Other factors that affect Other factors that affect college studentscollege students

Alcohol and binge drinkingAlcohol and binge drinking Eating disordersEating disorders Vegetarian lifestyleVegetarian lifestyle

chapt01 lecture nutrition

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