1 behavioral choice theory and obesity leonard h. epstein, ph.d. distinguished professor of...

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Behavioral Choice Theory and Behavioral Choice Theory and ObesityObesity

Leonard H. Epstein, Ph.D. Leonard H. Epstein, Ph.D.

Distinguished Professor of Pediatrics and Distinguished Professor of Pediatrics and Social and Preventive MedicineSocial and Preventive Medicine

University at Buffalo School of Medicine University at Buffalo School of Medicine and Biomedical Sciencesand Biomedical Sciences

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Behavioral Choice TheoryBehavioral Choice Theory

Behavioral choice theory, or Behavioral choice theory, or behavioral behavioral economicseconomics involves understanding involves understanding factors that influence choice between factors that influence choice between two or more alternativestwo or more alternatives

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Choice and behavioral interventionsChoice and behavioral interventions

Task of intervention or treatment is to shift Task of intervention or treatment is to shift choice from an unhealthy, highly choice from an unhealthy, highly reinforcing behavior to less reinforcing, but reinforcing behavior to less reinforcing, but more healthy alternativesmore healthy alternatives– Choosing to be more active rather than Choosing to be more active rather than

sedentary sedentary – Choosing to eat healthier, rather than less Choosing to eat healthier, rather than less

healthy eatinghealthy eating

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Choice: now or later? Choice: now or later?

Concurrent choices Concurrent choices – Eating junk food or healthy food nowEating junk food or healthy food now– Being sedentary or active nowBeing sedentary or active now– Relative reinforcing valueRelative reinforcing value

Delayed choicesDelayed choices– Eating healthy now to lose weight laterEating healthy now to lose weight later– Being more active now to be stronger and faster Being more active now to be stronger and faster

laterlater– Delay discounting or behavioral impulsivityDelay discounting or behavioral impulsivity

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Topics to be addressed from perspective Topics to be addressed from perspective of behavioral economic theoryof behavioral economic theory

Basic science of choice, using drug self-Basic science of choice, using drug self-administration and eating as examplesadministration and eating as examples– The role of choice in establishing motivationThe role of choice in establishing motivation

What happens to energy balance (the What happens to energy balance (the relationship between energy intake and energy relationship between energy intake and energy expenditure) or body composition when you expenditure) or body composition when you modify sedentary behaviors?modify sedentary behaviors?

What is the role of food pricing on choice?What is the role of food pricing on choice?

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Experimental Design: Alcohol Experimental Design: Alcohol DependenceDependence

Rats randomized to control, intermittent free choice (once Rats randomized to control, intermittent free choice (once per week), continuous free choice, or forced intake of per week), continuous free choice, or forced intake of ethanol ethanol

Became dependent on ethanol over 32 weeks of drug Became dependent on ethanol over 32 weeks of drug administration administration

Animals kept ethanol-abstinent for 3 months, during which Animals kept ethanol-abstinent for 3 months, during which time they showed withdrawal (change in pain threshold, time they showed withdrawal (change in pain threshold, hyperthermia, inactivity)hyperthermia, inactivity)

Animals then provided self-administration test Animals then provided self-administration test

Wolffgramm, J., Heyne, A. (1995). From controlled drug intake to loss of control: the Wolffgramm, J., Heyne, A. (1995). From controlled drug intake to loss of control: the irreversible development of drug addiction in the rat.irreversible development of drug addiction in the rat. Behavioural Brain Research, Behavioural Brain Research, 70, 77-94.70, 77-94.

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Wolffgramm, J., Heyne, A. (1995). From controlled drug intake to Wolffgramm, J., Heyne, A. (1995). From controlled drug intake to loss of control: the irreversible development of drug addiction in loss of control: the irreversible development of drug addiction in the rat Behavioural Brain Research, 70, 77-94.the rat Behavioural Brain Research, 70, 77-94.

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Controls Forced IntermittentFree Choice

ContinuousFree Choice

g/kg/day ethanol

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Experimental Design : Opiate Experimental Design : Opiate DependenceDependence

Rats randomized to control, choice or forced Rats randomized to control, choice or forced intake of etonitazene intake of etonitazene

Became dependent on opiate over 30 weeks of Became dependent on opiate over 30 weeks of drug administration drug administration

Animals kept opiate-abstinent for 19 weeks, Animals kept opiate-abstinent for 19 weeks, during which time they showed withdrawal during which time they showed withdrawal (change in pain threshold)(change in pain threshold)

Animals then provided self-administration test Animals then provided self-administration test

Wolffgramm, J., Heyne, A. (1995). From controlled drug intake to loss of control: the Wolffgramm, J., Heyne, A. (1995). From controlled drug intake to loss of control: the irreversible development of drug addiction in the rat.irreversible development of drug addiction in the rat. Behavioural Brain Research, Behavioural Brain Research, 70, 77-94.70, 77-94.

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Wolffgramm, J., Heyne, A. (1995). From controlled drug intake to loss Wolffgramm, J., Heyne, A. (1995). From controlled drug intake to loss of control: the irreversible development of drug addiction in the ratof control: the irreversible development of drug addiction in the ratBehavioural Brain Research, 70, 77-94.Behavioural Brain Research, 70, 77-94.

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Controls Forced Free Choice

ug/kg/day Etonitazene

10Elsmore, T. F., Fletcher, G. V., Conrad, D. G., & Sodetz, F. J. (1980). Reduction of heroin intake in baboons by an economic constraint. Pharmacology, Biochemistry and Behavior, 13, 729-731.

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Choices for cocaine or Choices for cocaine or placebo placebo

0123456789

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ChoicesDrugPlacebo

Higgins, Bickel & Hughes. (1994). Influence of an alternative reinforcer on human cocaine self-administration. Life Sciences, 55, 179-187.

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Choices for cocaine or placebo Choices for cocaine or placebo

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$0.00 $0.50 $1.00 $2.00

First ExposureSecond Exposure

Higgins, Bickel & Hughes. (1994). Influence of an alternative reinforcer on human cocaine self-administration. Life Sciences, 55, 179-187.

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Hypothetical demand for foodHypothetical demand for food

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Hypothetical Demand CurveOutput Function

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Omax

ElasticInelastic

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Fixed Ratio

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Behavioral economic relationshipsBehavioral economic relationships

Relative reinforcing valueRelative reinforcing value– Determined by reinforcing value of the alternatives and the Determined by reinforcing value of the alternatives and the

cost of the alternativescost of the alternatives ElasticityElasticity

– The relationship between cost and consumptionThe relationship between cost and consumption» Elasticity = consumption Elasticity = consumption decreasesdecreases when price (response requirements) increase when price (response requirements) increase» Inelastic = consumption Inelastic = consumption does not decreasedoes not decrease when price (response requriements) increase when price (response requriements) increase

Cross-price elasticityCross-price elasticity– If increasing the price (response requirements) for commodity If increasing the price (response requirements) for commodity

A result in an increase in responding or consumption of B, A result in an increase in responding or consumption of B, that is evidcnce for substitution of B for Athat is evidcnce for substitution of B for A

» Reduce access to TV, will people be more active?Reduce access to TV, will people be more active?

– If increasing the price (response requirements) for commodity If increasing the price (response requirements) for commodity A result in a reduction in consumption of B, that is evidence A result in a reduction in consumption of B, that is evidence for complementary relationshipfor complementary relationship

» Reduce access to TV, will eating decrease? Reduce access to TV, will eating decrease?

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Fulton, Woodside & Shizgal (2000). Modulation of brain reward circuitry by leptin. Science, 287, 125-128.

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In such views, the prevalence of a particular In such views, the prevalence of a particular behavior, such as feeding, can be reduced either behavior, such as feeding, can be reduced either by decreasing the reward value it generates or by by decreasing the reward value it generates or by increasing the value of competing activitiesincreasing the value of competing activities..

If so, leptin could make complementary If so, leptin could make complementary contributions to energy balance by reducing food contributions to energy balance by reducing food reward while reward while enhancing the value of behaviors enhancing the value of behaviors incompatible with feedingincompatible with feeding..


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Does food reinforcement relate to Does food reinforcement relate to eating and obesity?eating and obesity?

If food reinforcement provides an index of how If food reinforcement provides an index of how motivated someone is to eat, then it would be motivated someone is to eat, then it would be expected that those high in food reinforcement expected that those high in food reinforcement would consume more food than those low in food would consume more food than those low in food reinforcementreinforcement

If food reinforcement is related to high energy If food reinforcement is related to high energy intake, then disorders that involve high energy intake, then disorders that involve high energy intake may be characterized by high levels of food intake may be characterized by high levels of food reinforcementreinforcement

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Epstein, Wright, Paluch,Leddy, Hawk, Jaroni, Saad,Crystal-Mansour, Lerman.(2004). Food hedonics andReinforcement as determinantsOf laboratory food intake in Smokers. Physiology andBehavior, 81, 511-517.

74 smokers studied•Food reinforcement

measured•Energy intake in ad-

lib snack eating task studied

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Study PopulationStudy Population

18 – 40 year olds (n=45 non-obese and 18 – 40 year olds (n=45 non-obese and n=29 obese)n=29 obese)

Non-smokersNon-smokers Not currently on a diet Not currently on a diet Not currently on any medications that Not currently on any medications that

affect appetite or eating (methylphenidate, affect appetite or eating (methylphenidate, etc)etc)

No eating disordersNo eating disorders Must like study foodsMust like study foods

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Study DesignStudy Design

Two visits to the laboratory – separated by 1 weekTwo visits to the laboratory – separated by 1 week

First visit = “taste test” First visit = “taste test”

– Measure energy intake of snack foodsMeasure energy intake of snack foods

– Take DNA sampleTake DNA sample

Second visit = food reinforcementSecond visit = food reinforcement

– Participants complete reinforcement taskParticipants complete reinforcement task

– Height/weight obtainedHeight/weight obtained

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Dopamine, Eating, and ObesityDopamine, Eating, and Obesity

Dopamine is released in the striatum during eating in Dopamine is released in the striatum during eating in rodents (rodents (Heffner et al., 1980; Hernandez & Hoebel, 1988Heffner et al., 1980; Hernandez & Hoebel, 1988) and ) and humans (humans (Small et al., 2003Small et al., 2003))

In genetically obese mice (ob/ob), administration of In genetically obese mice (ob/ob), administration of dopamine normalizes body weight (dopamine normalizes body weight (Bina & Cincotta, 2000Bina & Cincotta, 2000))

In obese humans, dopamine agonists reduce energy In obese humans, dopamine agonists reduce energy intake intake (Leddy, et al, 2004)(Leddy, et al, 2004)

Chronic treatment with antipsychotic drugs, which block Chronic treatment with antipsychotic drugs, which block the dopamine receptors, increases obesity risk (the dopamine receptors, increases obesity risk (American American Diabetes Association, 2004Diabetes Association, 2004))

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Dopamine D2 ReceptorDopamine D2 Receptor

DRD2 plays a central role in the neurobiology of DRD2 plays a central role in the neurobiology of addiction (addiction (Volkow & Fowler, 2003Volkow & Fowler, 2003))

The DRD2 may be a common neurobiological The DRD2 may be a common neurobiological substrate underlying drug addiction and obesity substrate underlying drug addiction and obesity ((Volkow & Wise, 2005Volkow & Wise, 2005))

Imaging studies in humans show that obese Imaging studies in humans show that obese individuals have reduced expression of DRD2 individuals have reduced expression of DRD2 similar in magnitude to reductions reported in similar in magnitude to reductions reported in drug-addicted subjects (drug-addicted subjects (Wang et al., 2001Wang et al., 2001))

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Taq 1 Al Allele of the DRD2Taq 1 Al Allele of the DRD2

The presence of The presence of at least one copyat least one copy of the Taq 1 A1 of the Taq 1 A1 allele of the DRD2 is associated with a 30-40% allele of the DRD2 is associated with a 30-40% reduction in the density of DRD2 (reduction in the density of DRD2 (Noble et al., 1994; Noble et al., 1994; Jonsson et al., 1999Jonsson et al., 1999).).

The Taq 1 A1 allele increases the risk for drug The Taq 1 A1 allele increases the risk for drug addiction (addiction (Volkow et al., 1993 & Wang et al., 2001Volkow et al., 1993 & Wang et al., 2001), alcohol ), alcohol abuse (abuse (Munafo et al., 2005Munafo et al., 2005), smoking (), smoking (Lee, 2003Lee, 2003) and ) and obesity (obesity (Fang et al., 2005Fang et al., 2005).).

A current hypothesis is that reduced sensitivity to A current hypothesis is that reduced sensitivity to dopamine in individuals with the Taq 1 A1 leads to a dopamine in individuals with the Taq 1 A1 leads to a need for excess dopamine in the synapse (need for excess dopamine in the synapse (Bowirrat & Bowirrat & Oscar-Berman, 2005Oscar-Berman, 2005).).

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Energy intake by food reinforcement groupEnergy intake by food reinforcement groupEnergy intake by food reinforcement group

Reinforcement group

Low High

En

erg

y in

take

(kc

al)

0

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400

600

800

Epstein, Temple, Neaderhiser, Salis, Erbe, & Leddy (2007). Food reinforcement, the dopamine D2 receptor genotype and energy intake in obese and non-obese humans. Manuscript in review.

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Obese Individuals Find Food More Obese Individuals Find Food More Reinforcing than Non-Obese Reinforcing than Non-Obese

4 8 16 32 64 128 256 512 1024

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tal B

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sses

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1500

2000 *

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Obese Individuals with the Taq 1 A1 Allele Obese Individuals with the Taq 1 A1 Allele Have the Highest Levels of Food Have the Highest Levels of Food

ReinforcementReinforcement

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mb

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of

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tto

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resses

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800Non-Obese/A2/A2 (n=25)Non-Obese/A1/A1 or A1/A2 (n=20)Obese/A2/A2 (n=12)Obese/A1/A1 or A1/A2 (n=17)

4 8 16 32 64 128 256 512 1024 Non-Obese Obese

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A2/A2A1/A1 or A1/A2 *

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Taq 1 A1 Interacts with Food Reinforcement to Taq 1 A1 Interacts with Food Reinforcement to Increase Energy IntakeIncrease Energy Intake

Low High

En

erg

y C

on

sum

ed (

KC

al)

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200

400

600

800

1000A2/A2 A1/A2 or A1/A1

Food Reinforcement Level

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Previous research in smokersPrevious research in smokers

Taq 1 A1 allele + Taq 1 A1 allele + high food high food reinforcement = reinforcement = increased energy increased energy intake intake

Observed in primarily Observed in primarily non-obese smokers non-obese smokers

Epstein, Wright, Paluch, Leddy, Hawk, Jaroni, et al. (2004b). The relationship between food reinforcement and dopamine genotypes on food intake in smokers. American Journal of Clinical Nutrition, 80, 82-88.

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Choice is important to establish drugs as Choice is important to establish drugs as rewardsrewards

Relative reinforcing value depends on Relative reinforcing value depends on behavioral cost and alternativesbehavioral cost and alternatives

There are genetic and neurobiological There are genetic and neurobiological factors that influence choicefactors that influence choice

Summary of basic science studies

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Reinforcing value of physical activity: Reinforcing value of physical activity: DesignDesign

Children in three categories:Children in three categories:– Non-obese (<20% overweight) Non-obese (<20% overweight) – Moderately obese (20-80% overweight) Moderately obese (20-80% overweight) – Very obese (>80% overweight)Very obese (>80% overweight)

Provided access to a moderately liked vigorous Provided access to a moderately liked vigorous activity at a constant variable ratio (VR2) activity at a constant variable ratio (VR2) reinforcement schedule versus a highly liked reinforcement schedule versus a highly liked sedentary activity with the schedule varied sedentary activity with the schedule varied from VR2 to VR32. from VR2 to VR32.

Epstein, Smith, Vara, & Rodefer. (1991). Behavioral economic analysis of activity choice in obese children. Health Psychology, 10, 311-316.

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Vigorous/Sedentary VR Schedules of Reinforcement

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ec)

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25

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75

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200Non-obese Moderately Obese Very Obese

2/2 2/4 2/8 2/16 2/32

Epstein, Smith, Vara, & Rodefer. (1991). Behavioral economic analysis of activity choice in obese children. Health Psychology, 10, 311-316.

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How can reducing sedentary How can reducing sedentary behavior influence energy balance?behavior influence energy balance?

Sedentary behaviors can reduce the Sedentary behaviors can reduce the opportunity to be opportunity to be physically activephysically active– Reducing sedentary behaviors may increase Reducing sedentary behaviors may increase

physical activityphysical activity Sedentary behaviors can increase the Sedentary behaviors can increase the

opportunities to opportunities to eateat– Reducing sedentary behaviors can reduce Reducing sedentary behaviors can reduce

energy intake and dietary fat intakeenergy intake and dietary fat intake

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Effects of decreasing sedentary behavior Effects of decreasing sedentary behavior versus increasing activity on weight versus increasing activity on weight

change in obese childrenchange in obese children

Obese 8-12 year-old children from 61 Obese 8-12 year-old children from 61 families randomized to groups that targeted:families randomized to groups that targeted:– Increased physical activityIncreased physical activity– Decreased sedentary behaviorDecreased sedentary behavior– Combined increased physical activity, Combined increased physical activity,

decreased sedentary behaviordecreased sedentary behavior Provided 4 month intensive treatment, Provided 4 month intensive treatment,

followed at 12 month post randomizationfollowed at 12 month post randomization

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Effects of decreasing sedentary behavior Effects of decreasing sedentary behavior versus increasing activity on weight versus increasing activity on weight

change in obese childrenchange in obese children Traffic light diet used for reducing calories, Traffic light diet used for reducing calories,

increasing nutrient density and balancing nutrient increasing nutrient density and balancing nutrient intake intake

Increase activity goals from 30-150 points/weekIncrease activity goals from 30-150 points/week– 300-1500 kcal/week for a 150 lb person300-1500 kcal/week for a 150 lb person

Decrease sedentary from 35 hours/week to goal of Decrease sedentary from 35 hours/week to goal of 15 hours/week 15 hours/week – decreases in 5 hour incrementsdecreases in 5 hour increments

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Epstein et al. (1995). Effects of decreasing sedentary behavior and increasing Epstein et al. (1995). Effects of decreasing sedentary behavior and increasing physical activity on weight change in obese children. physical activity on weight change in obese children. Health Psychology, 14,Health Psychology, 14, 109-115.109-115.

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Epstein et al. (1995). Effects of decreasing sedentary behavior and Epstein et al. (1995). Effects of decreasing sedentary behavior and increasing physical activity on weight change in obese children. increasing physical activity on weight change in obese children. Health Health Psychology, 14,Psychology, 14, 109-115. 109-115.

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Change in liking for physical activity

ExerciseCombinedReduce sedentary

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What happens to eating and activity when What happens to eating and activity when you change sedentary behavior?you change sedentary behavior?

58 families with non-obese and obese 12-15 year-old children 58 families with non-obese and obese 12-15 year-old children – Participated in a 9 week experiment Participated in a 9 week experiment

» Baseline: maintain usual pattern of sedentary behavior, physical activity and energy Baseline: maintain usual pattern of sedentary behavior, physical activity and energy intake. intake.

» Increase sedentary behavior by 25% to 50% of baseline Increase sedentary behavior by 25% to 50% of baseline » Decrease sedentary behavior by 25% to 50% of baselineDecrease sedentary behavior by 25% to 50% of baseline

– Targeted sedentary behaviors were watching TV or VCR, playing computer Targeted sedentary behaviors were watching TV or VCR, playing computer games, or using the internet.games, or using the internet.

Activity measured using tri-axial accelerometerActivity measured using tri-axial accelerometer Dietary intake from repeated 24-hour phone dietary recallsDietary intake from repeated 24-hour phone dietary recalls

Epstein LH, Paluch RA, Consalvi A, Riordan K, Scholl T. Effects of manipulating sedentary behavior on physical activity and food intake. J Pediatr. 2002; 140:334-339.

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Changes in targeted sedentary behaviors from Changes in targeted sedentary behaviors from basleine during increase and decrease phasesbasleine during increase and decrease phases

Increase Decrease

Ch

ang

e in

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- 150

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* * *

* * *

Epstein, L. H., Roemmich, J. N., Paluch, R. A., & Raynor, H. A. (2005b). Physical activity as a substitute for sedentary behavior in youth. Annals of Behavioral Medicine, 29, 200-209.

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What happens to activity in adolescents What happens to activity in adolescents when you change sedentary behavior?when you change sedentary behavior?

When sedentary behaviors are When sedentary behaviors are increasedincreased– There is a reduction in physical activityThere is a reduction in physical activity– GirlsGirls show greater reductions in physical activity than show greater reductions in physical activity than

boysboys When sedentary behaviors are decreasedWhen sedentary behaviors are decreased

– Overall, no change in physical activity Overall, no change in physical activity – But:But:

» BoysBoys show bigger and significant increases in activity compared show bigger and significant increases in activity compared to to girlsgirls

» Non-obeseNon-obese youth substitute increases in physical activity, but youth substitute increases in physical activity, but obeseobese don’t don’t

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Epstein, L. H., Roemmich, J. N., Paluch, R. A., & Raynor, H. A. (2005). The influence of changes in sedentary behavior on energy and macronutrient intake in youth. American Journal of Clinical Nutrition, 81, 361-366.

Phases

Baseline Increase Decrease

Energy intake (kcal/day) associated withtargeted sedentary behaviors

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Energy intake in association with watching television influenced more by reducing than increasing sedentary behaviors

Design:16 of the non-overweight12-16 year-old youth who did not underreport energy Intake were studiedin the same 3-phase within subjects design

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Can reducing television watching Can reducing television watching modify z-BMI in 4-7 year-old youth?modify z-BMI in 4-7 year-old youth? Most programs to change body weight Most programs to change body weight

involve combinations of programs to involve combinations of programs to decrease energy intake and increase decrease energy intake and increase physical activityphysical activity– Reducing television watching may have an Reducing television watching may have an

impact on body weight since the effects on impact on body weight since the effects on reducing energy intake are potentially so strongreducing energy intake are potentially so strong

– Even if the effects on physical activity are more Even if the effects on physical activity are more limitedlimited

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Can reducing television watching Can reducing television watching modify z-BMI in 4-7 year-old youth?modify z-BMI in 4-7 year-old youth?

70 4-7 year-old children at the 7570 4-7 year-old children at the 75thth BMI percentile or BMI percentile or greater were randomized to:greater were randomized to:– A TV and computer game reduction groupA TV and computer game reduction group

» Goal of reducing these targeted sedentary behaviors by 50%Goal of reducing these targeted sedentary behaviors by 50%» Provided TV Allowance monitors as well as monthly newsletters.Provided TV Allowance monitors as well as monthly newsletters.

Newsletter provided ideas for substitutes for watching television and Newsletter provided ideas for substitutes for watching television and ideas for parentingideas for parenting

– Monitoring control groupMonitoring control group » TV Allowance devices but no reduction goalsTV Allowance devices but no reduction goals» Received newsletter without ideas for substitutes or parentingReceived newsletter without ideas for substitutes or parenting

– Activity measured using accelerometersActivity measured using accelerometers– Dietary intake measured using food frequency questionnaire Dietary intake measured using food frequency questionnaire

(Rockett) (Rockett)

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Months

-6 0 6 12 18 24

Ho

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of t

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Control groupTV reduction group

Epstein, L.H., Roemmich, J.N., Robinson, J.L., Paluch, R.A., Winiewicz, D.D., Fuerch, J.H. & Robinson, T.N. (2007). A randomized trial on the effects of reducing television on BMI in young children. Manuscript submitted for publication.

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X Data

-6 0 6 12 18 24

zBM

I

1.30

1.35

1.40

1.45

1.50

1.55

1.60

1.65

1.70



52

Months

-6 0 6 12 18 24

Ene

rgy

inta

ke/d

ay

1100

1200

1300

1400

1500

1600



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Can reducing television watching Can reducing television watching modify z-BMI in 4-7 year-old youth?modify z-BMI in 4-7 year-old youth?

A complementary relationship was observed for the A complementary relationship was observed for the relationship between changes in television watching and relationship between changes in television watching and energy intakeenergy intake– As television watching decreased, energy intake decreasedAs television watching decreased, energy intake decreased– No significant changes in physical activity, or a relationship No significant changes in physical activity, or a relationship

between television watching and physical activity were observedbetween television watching and physical activity were observed Results suggest that reducing television watching can Results suggest that reducing television watching can

reduce BMI in young children and the effect is primarily reduce BMI in young children and the effect is primarily due to changes in energy intake that occur when television due to changes in energy intake that occur when television watching is reduced watching is reduced

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Maternal obesity, price changes and Maternal obesity, price changes and food purchasing food purchasing

Participants were 47 25-50 year old mothers who were Participants were 47 25-50 year old mothers who were randomized to one of two groupsrandomized to one of two groups– Low energy dense food prices varied 25% above and below reference Low energy dense food prices varied 25% above and below reference

valuesvalues– High energy dense food prices varied 25% above and below reference High energy dense food prices varied 25% above and below reference

valuesvalues Purchases of 60 foods (30 low energy dense and 30 high energy Purchases of 60 foods (30 low energy dense and 30 high energy

dense) were studied in each of two income conditions - dense) were studied in each of two income conditions - $15/person and $30/person/week$15/person and $30/person/week

Foods represented usual foods purchased for familyFoods represented usual foods purchased for family Obese and non-obese mothers did not differ in minority status or Obese and non-obese mothers did not differ in minority status or

family incomefamily income

Epstein, L.H., Dearing, K.K., Paluch, R.A., Cho, D.D. (In Review) Price influences purchasing of low and high-nutrient foods.Epstein, L.H., Dearing, K.K., Paluch, R.A., Cho, D.D. (In Review) Price influences purchasing of low and high-nutrient foods.

55Own-price elasticity for low and high energy dense foods purchased (Mean + SEM).

A

Percentage of HED reference price

50 75 100 125 150D

eman

d fo

r hig

h en

ergy

den

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ods

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$30/person income $15/person income

Percentage of LED reference price

50 75 100 125 150

Dem

and

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non obese obese

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ense

foo

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75% HED reference price100% HED reference price125% HED reference price

Number of low energy dense items purchased (Mean + SEM) when price of high

energy-dense foods was changed for obese and lean mothers.

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ResultsResults Price reductions increase purchases of healthy foods Price reductions increase purchases of healthy foods Price increases decrease purchase of unhealthy foodsPrice increases decrease purchase of unhealthy foods Non-obese women are more sensitive to own-price Non-obese women are more sensitive to own-price

elasticity than obese womenelasticity than obese women Non-obese women substitute lower energy dense foods Non-obese women substitute lower energy dense foods

for higher energy dense foods when the price of high for higher energy dense foods when the price of high energy dense foods are increasedenergy dense foods are increased– Could the failure of obese women to respond to price Could the failure of obese women to respond to price

manipulations for high energy dense foods be due to higher manipulations for high energy dense foods be due to higher reinforcing value of food in these women?reinforcing value of food in these women?

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SummarySummary Sedentary behaviors can be decreased through parental Sedentary behaviors can be decreased through parental

intervention and/or new technologyintervention and/or new technology Behavioral economics is a theoretical approach that can be Behavioral economics is a theoretical approach that can be

used to study how used to study how – Changes in sedentary behavior influence energy balance behaviorsChanges in sedentary behavior influence energy balance behaviors– Price changes influence food purchasesPrice changes influence food purchases

Behavioral economics can be studied at the genetic, Behavioral economics can be studied at the genetic, physiological, environmental or behavioral levelsphysiological, environmental or behavioral levels

Choice is important to understand factors that influence the Choice is important to understand factors that influence the motivation to engage in healthier behaviorsmotivation to engage in healthier behaviors

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AcknowledgementsAcknowledgements Brian Saelens, Ph.D.Brian Saelens, Ph.D. Holly Raynor, Ph.D.Holly Raynor, Ph.D. James Roemmich, Ph.D.James Roemmich, Ph.D. Rocco Paluch, M.S.Rocco Paluch, M.S. Jenn Temple, Ph.D.Jenn Temple, Ph.D. John Leddy, M.D.John Leddy, M.D. Tom Robinson, M.D.Tom Robinson, M.D.

1 behavioral choice theory and obesity leonard h. epstein, ph.d. distinguished professor of...

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