Energy Balance and Energy Balance and Weight ControlWeight Control

Obesity is a Growing Obesity is a Growing ProblemProblem 127 million adults in the U.S. are 127 million adults in the U.S. are

overweight, 60 million obese, and overweight, 60 million obese, and 9 million severely obese. 9 million severely obese.

64.5 percent of U.S. adults are 64.5 percent of U.S. adults are overweight (BMIoverweight (BMI≥≥25)25)

30.5 percent are obese (BMI30.5 percent are obese (BMI≥≥30)30) 4.7 percent are severely obese 4.7 percent are severely obese

(BM(BM≥≥40)40)

Obesity Trends* Among U.S. Obesity Trends* Among U.S. AdultsAdultsBRFSS, 1985BRFSS, 1985

Source: Mokdad A H, et al. J Am Med Assoc 1999;282:16, 2001;286:10.

Obesity Trends* Among U.S. Obesity Trends* Among U.S. AdultsAdultsBRFSS, 2001BRFSS, 2001

Source: Mokdad A H, et al. J Am Med Assoc 1999;282:16, 2001;286:10.

Prevalence of Obesity Prevalence of Obesity in Ohioin Ohio

0

5

10

15

20

25

1991 1995 1998 1999 2000 2001

% of adults

Obesity: A Major Obesity: A Major Health IssueHealth Issue Obesity is the No. 2 preventable cause of Obesity is the No. 2 preventable cause of

death and disability (smoking is #1)death and disability (smoking is #1) Obesity is associated with increased risk Obesity is associated with increased risk

of heart disease, stroke, gallbladder of heart disease, stroke, gallbladder disease, cancer, osteoarthritis, sleep disease, cancer, osteoarthritis, sleep apneaapnea

Obesity-related health problems cost $75 Obesity-related health problems cost $75 billion annually (2003 data)billion annually (2003 data)

The public pays about $39 billion a year -- The public pays about $39 billion a year -- or about $175 per person -- for obesity or about $175 per person -- for obesity through Medicare and Medicaid programsthrough Medicare and Medicaid programs

Health Risks of Health Risks of ObesityObesity Cardiovascular diseaseCardiovascular disease CancerCancer HypertensionHypertension Bone/joint disordersBone/joint disorders Type 2 diabetesType 2 diabetes

Energy BalanceEnergy Balance

Relationship between energy intake and Relationship between energy intake and energy expendedenergy expended

Positive energy balancePositive energy balance– Energy intake Energy intake >> energy expended energy expended– Results in weight gainResults in weight gain

Negative energy balanceNegative energy balance– Energy intake Energy intake << energy expended energy expended– Results in weight lossResults in weight loss

Estimating Kcal Estimating Kcal Content in Food Content in Food

Bomb calorimeterBomb calorimeter Burns food inside a Burns food inside a

chamber surrounded chamber surrounded by waterby water

Heat is given off as Heat is given off as food is burnedfood is burned

The increase in The increase in water temperature water temperature indicates the amount indicates the amount of energy in the foodof energy in the food

Use and Storage of FatUse and Storage of Fat

Most fat is stored directly into Most fat is stored directly into adipose tissueadipose tissue

Body has unlimited ability to store Body has unlimited ability to store fat (as fat) fat (as fat)

Fat will remain as fat for storage Fat will remain as fat for storage Physical activity encourages the Physical activity encourages the

burning of dietary fatburning of dietary fat

Use and Storage of Use and Storage of CHOCHO Limited CHO can be stored as glycogenLimited CHO can be stored as glycogen Most CHO is used as a energy source to Most CHO is used as a energy source to

meet immediate energy needsmeet immediate energy needs Excessive CHO will be converted to fat Excessive CHO will be converted to fat

(for storage)(for storage) Body prefers to use CHO as energy Body prefers to use CHO as energy

sourcesource Only excess intake of CHO and protein Only excess intake of CHO and protein

will be turned into fatwill be turned into fat

Use and Storage of Use and Storage of ProteinProtein Protein is primarily used for tissue Protein is primarily used for tissue

synthesissynthesis Excess protein is used for energyExcess protein is used for energy Some protein will be synthesized Some protein will be synthesized

into fat (for storage)into fat (for storage) Protein cannot be stored as Protein cannot be stored as

proteinprotein

Energy In Vs. Energy Energy In Vs. Energy OutOut

NEAT

Basal Metabolism

Dietary Intake Physical Activity

Thermic Effect of food

Basal Metabolism Basal Metabolism

The minimum energy expended to The minimum energy expended to keep a resting, awake body alivekeep a resting, awake body alive

~60-70% of the total energy needs~60-70% of the total energy needs Includes energy needed for Includes energy needed for

maintaining a heartbeat, respiration, maintaining a heartbeat, respiration, body temperaturebody temperature

Amount of energy needed varies Amount of energy needed varies between individualsbetween individuals

Approximately 0.9 kcal/kg/hrApproximately 0.9 kcal/kg/hr

Estimate Basal Estimate Basal MetabolismMetabolism

Female: Wt (kg) x 0.9 kcals/hour x Female: Wt (kg) x 0.9 kcals/hour x 2424

50 kg (110 lb) x 0.9 x 24 50 kg (110 lb) x 0.9 x 24 = = 1080 kcals 1080 kcals

Male: Wt (kg) x 1 kcal/hour x 24Male: Wt (kg) x 1 kcal/hour x 24

100 kg (220 lb) x 1 x 24 = 100 kg (220 lb) x 1 x 24 =

2400 kcals2400 kcals

Calculate Your BMRCalculate Your BMR

________ x ______ x ________ x ______ x 24 24

= ____ kcals/day= ____ kcals/day

This is only an This is only an estimate!!estimate!!

Factors that Increase Factors that Increase Basal MetabolismBasal Metabolism

Body surface area (weight, height)Body surface area (weight, height) Male genderMale gender Body temperatureBody temperature Thyroid hormoneThyroid hormone Nervous system activityNervous system activity Kcal intakeKcal intake PregnancyPregnancy Use of caffeine and tobaccoUse of caffeine and tobacco

Factors that Decrease Factors that Decrease Basal MetabolismBasal Metabolism Age Age

– – – 2% drop each decade after 302% drop each decade after 30 Low calorie diet Low calorie diet

– 10-20% decrease10-20% decrease

Physical ActivityPhysical Activity

Increases energy expenditure Increases energy expenditure beyond BMRbeyond BMR

Varies widely among individualsVaries widely among individuals More activity, more energy More activity, more energy

burnedburned Lack of activity is the major cause Lack of activity is the major cause

of obesity of obesity

Thermic Effect of Food Thermic Effect of Food (TEF)(TEF)

Energy used to digest, absorb, and Energy used to digest, absorb, and metabolize food nutrientsmetabolize food nutrients

““Sales tax” of total energy consumedSales tax” of total energy consumed ~5-10% above the total energy ~5-10% above the total energy

consumedconsumed TEF is higher for CHO and protein than TEF is higher for CHO and protein than

fatfat Less energy is used to transfer dietary Less energy is used to transfer dietary

fat into adipose storesfat into adipose stores

Nonexercise Activity Nonexercise Activity Thermogenesis (NEAT)Thermogenesis (NEAT) Nonvoluntary physical activity Nonvoluntary physical activity

triggered by overeatingtriggered by overeating FidgetingFidgeting Maintenance of muscle toneMaintenance of muscle tone Maintenance of postureMaintenance of posture Overeating increases sympathetic Overeating increases sympathetic

nervous system activitynervous system activity Resists weight gainResists weight gain

Measurement of Measurement of Body’s Energy NeedsBody’s Energy Needs Direct calorimetryDirect calorimetry

– Measures heat output from the body Measures heat output from the body using an insulated chamberusing an insulated chamber

– Expensive and complexExpensive and complex Indirect calorimetryIndirect calorimetry

– Measures the amount of oxygen a Measures the amount of oxygen a person usesperson uses

– A relationship exists between the A relationship exists between the body’s use of energy and oxygenbody’s use of energy and oxygen

Food Guide Pyramid Food Guide Pyramid Energy EstimatesEnergy Estimates 1600 kcals – sedentary women, 1600 kcals – sedentary women,

some older adultssome older adults 2200 kcals – Children, teen girls, 2200 kcals – Children, teen girls,

active women, most menactive women, most men 2800 kcals – teen boys, active 2800 kcals – teen boys, active

men, very active womenmen, very active women

Food Guide Pyramid Food Guide Pyramid Calorie EstimatesCalorie Estimates Sedentary: 25-30 kcal/kgSedentary: 25-30 kcal/kg Moderate activity: 35 kcal/kgModerate activity: 35 kcal/kg Heavy activity: 40 kcal/kgHeavy activity: 40 kcal/kg

Energy Needs from US Energy Needs from US Dietary GuidelinesDietary Guidelines

What is a Healthy Body What is a Healthy Body Weight?Weight? Based on how you feel, weight Based on how you feel, weight

history, fat distribution, family history, fat distribution, family history of obesity-related disease, history of obesity-related disease, current health status, and current health status, and lifestylelifestyle

Current height/weight standards Current height/weight standards only provide guidesonly provide guides

A Healthy Body WeightA Healthy Body Weight

What is the lowest weight What is the lowest weight maintained for more than a year maintained for more than a year as an adult?as an adult?

What weight was maintained What weight was maintained without constantly feeling without constantly feeling hungry?hungry?

Establish a “personal” healthy Establish a “personal” healthy weightweight

Body Mass Index (BMI)Body Mass Index (BMI)

The preferred weight-for-height The preferred weight-for-height standard standard

Calculation:Calculation:

Body wt (in kg) OR Body wt (in lbs) x 703.1

[Ht (in m)]2 [Ht (in inches)]2

Health risks increase when BMI is > 25

BMI is Not a Measure BMI is Not a Measure of Body Fatnessof Body Fatness

HeightHeight 6'3" 6'3" HeightHeight 6'3" 6'3" WeightWeight 220 lbs 220 lbs WeightWeight 220 220 lbs lbs BMIBMI 27.5 27.5 BMI BMI 27.527.5

BMI Does Not Measure BMI Does Not Measure Body FatBody Fat However, most However, most

people with high people with high BMIs are overfatBMIs are overfat

BMI and HealthBMI and Health

Below 18.5Below 18.5 UnderweightUnderweight

18.5 – 24.918.5 – 24.9 NormalNormal

25.0 – 29.925.0 – 29.9 OverweightOverweight

Monitor for riskMonitor for risk

30.0 and Above30.0 and Above ObeseObese

Increased health Increased health riskrisk

40.0 and above40.0 and above Severely obeseSeverely obese

Major health riskMajor health risk

Overweight (BMI 25-Overweight (BMI 25-30) Monitor for30) Monitor for HypertensionHypertension Elevated LDL-cholesterolElevated LDL-cholesterol Family history of obesity, CVD, Family history of obesity, CVD,

certain cancerscertain cancers Pattern of fat distributionPattern of fat distribution Elevated blood glucose: diabetes, Elevated blood glucose: diabetes,

insulin resistanceinsulin resistance

Perspective on WeightPerspective on Weight

Unrealistic goalsUnrealistic goals Listen to body’s cues (for hunger)Listen to body’s cues (for hunger) Eat a healthy dietEat a healthy diet Physical activityPhysical activity ““Size acceptance”Size acceptance”

ObesityObesity

Excessive amount of body fatExcessive amount of body fat– Women with > 35% body fatWomen with > 35% body fat– Men with > 25% body fatMen with > 25% body fat

Increased risk for health Increased risk for health problems problems

Are usually overweight, but can Are usually overweight, but can have healthy BMI and high % fathave healthy BMI and high % fat

Measurements using calipersMeasurements using calipers

Estimation of Body FatEstimation of Body Fat

Underwater Underwater weighing Most weighing Most accurateaccurate– Fat is less dense Fat is less dense

than lean tissuethan lean tissue– Fat floatsFat floats

Problems withProblems with– ChildrenChildren– ElderlyElderly– Very largeVery large– Fear of waterFear of water

Estimation of Body FatEstimation of Body Fat

Bioelectrical impedanceBioelectrical impedance– Low-energy current to the body that measures Low-energy current to the body that measures

the resistance of electrical flowthe resistance of electrical flow– Fat is resistant to electrical flow; the more the Fat is resistant to electrical flow; the more the

resistance, the more body fat you haveresistance, the more body fat you have DEXA (dual x-ray photon absorptiometry)DEXA (dual x-ray photon absorptiometry)

– An X-ray body scan that allows for the An X-ray body scan that allows for the determination of body fatdetermination of body fat

Infrared lightInfrared light– Assess the interaction of fat and protein in the Assess the interaction of fat and protein in the

arm musclearm muscle

Skinfold ThicknessSkinfold Thickness

Accurate withAccurate with TrainingTraining Good calipersGood calipers Multiple sitesMultiple sites Multiple Multiple

measurementsmeasurements

Health Problems Health Problems Associated with Excess Associated with Excess Body FatBody Fat Surgical riskSurgical risk Lung (pulmonary) Lung (pulmonary)

diseasedisease Sleep apneaSleep apnea HTNHTN CVDCVD Bone and joint Bone and joint

disorders (gout, disorders (gout, osteoarthritis)osteoarthritis)

GallstonesGallstones Cancers (breast, Cancers (breast,

colon, pancreas, colon, pancreas, gallbladder)gallbladder)

InfertilityInfertility Pregnancy- Pregnancy-

difficult deliverydifficult delivery Reduced agilityReduced agility Early deathEarly death

Desirable % Body FatDesirable % Body Fat

Men: 8-25%Men: 8-25% Women 20-35%Women 20-35%

Body Fat DistributionBody Fat Distribution

Upper-body (android) obesity--apple Upper-body (android) obesity--apple shapeshape

Associated with more heart disease, Associated with more heart disease, HTN, Type II DiabetesHTN, Type II Diabetes

Abdominal fat is released right into the Abdominal fat is released right into the liverliver

Encouraged by testosterone and Encouraged by testosterone and excessive alcohol intakeexcessive alcohol intake

Defined as waist measurement of > 40” Defined as waist measurement of > 40” for men and >35” for womenfor men and >35” for women

Body Fat DistributionBody Fat Distribution

Body Fat DistributionBody Fat Distribution

Lower-body (gynecoid) obesity--Pear Lower-body (gynecoid) obesity--Pear shapeshape

Encouraged by estrogen and Encouraged by estrogen and progesteroneprogesterone

After menopause, upper-body After menopause, upper-body obesity appearsobesity appears

Less health risk than upper-body Less health risk than upper-body obesityobesity

Juvenile-Onset ObesityJuvenile-Onset Obesity

Develops in infancy or childhoodDevelops in infancy or childhood Increase in theIncrease in the number number of of

adipose cellsadipose cells Adipose cells have long lifespan Adipose cells have long lifespan

and need to store fatand need to store fat Makes it difficult to lose the fat Makes it difficult to lose the fat

(weight loss)(weight loss)

Adult-Onset ObesityAdult-Onset Obesity

Develops in adulthoodDevelops in adulthood Fewer (numbers of) adipose cellsFewer (numbers of) adipose cells These adipose cells are larger These adipose cells are larger

(store excess amount of fat)(store excess amount of fat) If weight gain continues, the If weight gain continues, the

number of adipose cells can number of adipose cells can increaseincrease

Causes of ObesityCauses of Obesity

Nature vs NurtureNature vs Nurture Identical twins raised apart have similar Identical twins raised apart have similar

weightsweights Genetics account for ~40%-70% of Genetics account for ~40%-70% of

weight differencesweight differences Genes affect metabolic rate, fuel use, Genes affect metabolic rate, fuel use,

brain chemistry, body shapebrain chemistry, body shape Thrifty metabolism gene allows for more Thrifty metabolism gene allows for more

fat storage to protect against famine fat storage to protect against famine

Nature vs NurtureNature vs Nurture

Obesity tends to run in familiesObesity tends to run in families If both parents are normal weight – If both parents are normal weight –

10% chance of obesity in offspring10% chance of obesity in offspring If one parent is obese – 40% chanceIf one parent is obese – 40% chance If both parents obese – 80% chanceIf both parents obese – 80% chance

Is it genetics or learned eating Is it genetics or learned eating behavior?behavior?

Causes of ObesityCauses of Obesity

Nurture debateNurture debate Environmental factors influence Environmental factors influence

weightweight Learned eating habitsLearned eating habits Activity factor (or lack of)Activity factor (or lack of) Poverty and obesityPoverty and obesity Female obesity is rooted in childhood Female obesity is rooted in childhood

obesityobesity Male obesity appears after age 30Male obesity appears after age 30

Nature and NurtureNature and Nurture

Obesity is nurture allowing nature Obesity is nurture allowing nature to express itselfto express itself

Location of fat is influenced by Location of fat is influenced by geneticsgenetics

A child of obese parents must A child of obese parents must always be concerned about his always be concerned about his weightweight

Nature and NurtureNature and Nurture

The influence of The influence of environment is environment is apparent in the fact apparent in the fact that the prevalence that the prevalence of obesity has of obesity has increased increased dramatically in the dramatically in the US in the past 40 US in the past 40 yearsyears

Nurture TheoryNurture Theory

Eating habitsEating habits Overeating learned early in Overeating learned early in

childhoodchildhood Bottle vs breastBottle vs breast Urging children to eat more, clean Urging children to eat more, clean

their platestheir plates Use of food as a rewardUse of food as a reward

Food = LoveFood = Love

Shelly Thorene Photography

Eating Response to Eating Response to Non-Hunger CuesNon-Hunger Cues Boredom/depression/stressBoredom/depression/stress Food availabilityFood availability

– Increases overeatingIncreases overeating– Monotonous diet – eat lessMonotonous diet – eat less

Media triggersMedia triggers– Constant advertisementsConstant advertisements– Attractive footAttractive foot

Activity HabitsActivity Habits

U.S. Physical U.S. Physical activity decliningactivity declining– WorkWork– LeisureLeisure

U.S. obesity U.S. obesity risingrising

2005 U.S. Dietary 2005 U.S. Dietary Guidelines: ActivityGuidelines: Activity

To reduce the risk of chronic disease in To reduce the risk of chronic disease in adulthood: engage in adulthood: engage in at least 30 minutesat least 30 minutes of moderate-intensity physical activity…of moderate-intensity physical activity…on most days of the weekon most days of the week

To help manage body weight, engage To help manage body weight, engage in…60 minutesin…60 minutes of moderate to vigorous of moderate to vigorous intensity activity on most days of the intensity activity on most days of the weekweek

To sustain weight loss in adulthood: To sustain weight loss in adulthood: participate in at least participate in at least 60-90 minutes60-90 minutes of of daily moderate-intensity physical activity daily moderate-intensity physical activity while not exceeding calorie requirementswhile not exceeding calorie requirements

2005 U.S. Dietary 2005 U.S. Dietary Guidelines: ActivityGuidelines: Activity

However Exercise Alone is Generally Ineffective in Taking Weight Off!!

Nature Vs. NurtureNature Vs. Nurture

Those at risk for obesity will face Those at risk for obesity will face a lifelong struggle with weighta lifelong struggle with weight

Gene does not control destinyGene does not control destiny Increased physical activity, Increased physical activity,

moderate intake can promote moderate intake can promote healthy weighthealthy weight

Set Point TheorySet Point Theory

Weight is closely regulated by the bodyWeight is closely regulated by the body Genetically predetermined body weightGenetically predetermined body weight Body resists weight changeBody resists weight change Leptin assists in weight regulationLeptin assists in weight regulation Weight returns after weight lossWeight returns after weight loss Reduction in energy intake results in Reduction in energy intake results in

lower metabolic ratelower metabolic rate Ability to shift the set point weightAbility to shift the set point weight