Portion, package or tableware size for changing selection and consumption of food, alcohol and

395 Pages·2017·3.51 MB·English

CochraneDatabaseofSystematicReviews
Portion, package or tableware size for changing selection and
consumption of food, alcohol and tobacco (Review)
HollandsGJ,ShemiltI,MarteauTM,JebbSA,LewisHB,WeiY,HigginsJ,OgilvieD
HollandsGJ,ShemiltI,MarteauTM,JebbSA,LewisHB,WeiY,HigginsJ,OgilvieD.
Portion,packageortablewaresizeforchangingselectionandconsumptionoffood,alcoholandtobacco.
CochraneDatabaseofSystematicReviews2015,Issue9.Art.No.:CD011045.
DOI:10.1002/14651858.CD011045.pub2.
www.cochranelibrary.com
Portion,packageortablewaresizeforchangingselectionandconsumptionoffood,alcoholandtobacco(Review)
Copyright©2017TheAuthors.CochraneDatabaseofSystematicReviewspublishedbyJohnWiley&Sons,Ltd.onbehalfofTheCochrane
Collaboration.
TABLE OF CONTENTS
HEADER . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1
ABSTRACT . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1
PLAINLANGUAGESUMMARY . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3
SUMMARYOFFINDINGSFORTHEMAINCOMPARISON . . . . . . . . . . . . . . . . . . . 4
BACKGROUND . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7
OBJECTIVES . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8
METHODS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8
Figure1. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11
RESULTS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17
Figure2. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 19
Figure3. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 23
Figure4. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 25
Figure5. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 27
Figure6. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 28
Figure7. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 29
Figure8. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 31
Figure9. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 33
Figure10. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 34
Figure11. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 36
ADDITIONALSUMMARYOFFINDINGS . . . . . . . . . . . . . . . . . . . . . . . . . . 36
DISCUSSION . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 44
AUTHORS’CONCLUSIONS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 49
ACKNOWLEDGEMENTS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 53
REFERENCES . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 53
CHARACTERISTICSOFSTUDIES . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 67
DATAANDANALYSES . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 335
ADDITIONALTABLES . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 335
APPENDICES . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 363
FEEDBACK . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 387
WHAT’SNEW . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 390
HISTORY . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 391
CONTRIBUTIONSOFAUTHORS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 391
DECLARATIONSOFINTEREST . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 391
SOURCESOFSUPPORT . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 392
DIFFERENCESBETWEENPROTOCOLANDREVIEW . . . . . . . . . . . . . . . . . . . . . 392
INDEXTERMS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 393
Portion,packageortablewaresizeforchangingselectionandconsumptionoffood,alcoholandtobacco(Review) i
Copyright©2017TheAuthors.CochraneDatabaseofSystematicReviewspublishedbyJohnWiley&Sons,Ltd.onbehalfofThe
CochraneCollaboration.
[InterventionReview]
Portion, package or tableware size for changing selection and
consumption of food, alcohol and tobacco
GarethJHollands1a,IanShemilt2b,TheresaMMarteau1,SusanAJebb3,HannahBLewis4,YinghuiWei5,JulianHiggins6,David
Ogilvie7
1BehaviourandHealthResearchUnit,UniversityofCambridge,Cambridge,UK.2EPPI-Centre,UniversityCollegeLondon,London,
UK.3NuffieldDepartmentofPrimaryCareHealthSciences,UniversityofOxford,Oxford,UK.4MRCHumanNutritionResearch,
Cambridge,UK.5CentreforMathematicalSciences,SchoolofComputing, ElectronicsandMathematics,UniversityofPlymouth,
Plymouth,UK.6SchoolofSocialandCommunityMedicine,UniversityofBristol,Bristol,UK.7MRCEpidemiologyUnit,University
ofCambridge,Cambridge,UK
aGHandIScontributedequallytothiswork.bGHandIScontributedequallytothiswork
Contact address: Gareth J Hollands, Behaviour and Health Research Unit, University of Cambridge, Forvie Site, Robinson Way,
Cambridge,CB20SR,[email protected].
Editorialgroup:CochranePublicHealthGroup.
Publicationstatusanddate:Edited(nochangetoconclusions),commentaddedtoreview,publishedinIssue3,2017.
Citation: HollandsGJ,ShemiltI,MarteauTM,JebbSA,LewisHB,WeiY,HigginsJ,OgilvieD.Portion,packageortablewaresize
forchangingselectionandconsumptionoffood,alcoholandtobacco.CochraneDatabaseofSystematicReviews2015,Issue9.Art.No.:
CD011045.DOI:10.1002/14651858.CD011045.pub2.
Copyright©2017TheAuthors.CochraneDatabaseofSystematicReviewspublishedbyJohnWiley&Sons,Ltd.onbehalfofThe
CochraneCollaboration.ThisisanopenaccessarticleunderthetermsoftheCreativeCommonsAttributionLicence,whichpermits
use,distributionandreproductioninanymedium,providedtheoriginalworkisproperlycited.
ABSTRACT
Background
Overeatingandharmfulalcoholandtobaccousehavebeenlinkedtotheaetiologyofvariousnon-communicablediseases,whichare
amongtheleadingglobalcausesofmorbidityandprematuremortality.Aspeoplearerepeatedlyexposedtovaryingsizesandshapes
offood,alcoholandtobaccoproductsinenvironmentssuchasshops,restaurants,barsandhomes,thishasstimulatedpublichealth
policyinterestinproductsizeandshapeaspotentialtargetsforintervention.
Objectives
1) To assess the effects of interventions involving exposure to different sizes or sets of physical dimensions of a portion, package,
individual unit or item of tableware on unregulated selection or consumption of food, alcohol or tobacco products in adults and
children.
2)Toassesstheextenttowhichtheseeffectsmaybemodifiedbystudy,interventionandparticipantcharacteristics.
Searchmethods
WesearchedCENTRAL,MEDLINE,EMBASE,PsycINFO,eightotherpublishedorgreyliteraturedatabases,trialregistriesandkey
websitesuptoNovember2012,followedbycitationsearchesandcontactswithstudyauthors.Thisoriginalsearchidentifiedeligible
studiespublisheduptoJuly2013,whicharefullyincorporatedintothereview.Weconductedanupdatedsearchupto30January
2015butfurthereligiblestudiesarenotyetfullyincorporatedduetotheirminimalpotentialtochangetheconclusions.
Portion,packageortablewaresizeforchangingselectionandconsumptionoffood,alcoholandtobacco(Review) 1
Copyright©2017TheAuthors.CochraneDatabaseofSystematicReviewspublishedbyJohnWiley&Sons,Ltd.onbehalfofThe
CochraneCollaboration.
Selectioncriteria
Randomisedcontrolledtrialswithbetween-subjects(parallel-group)orwithin-subjects(cross-over)designs,conductedinlaboratory
orfieldsettings,inadultsorchildren.Eligiblestudiescomparedatleasttwogroupsofparticipants,eachexposedtoadifferentsizeor
shapeofaportionofafood(includingnon-alcoholicbeverages),alcoholortobaccoproduct,itspackageorindividualunitsize,orof
anitemoftablewareusedtoconsumeit,andincludedameasureofunregulatedselectionorconsumptionoffood,alcoholortobacco.
Datacollectionandanalysis
WeappliedstandardCochranemethodstoselecteligiblestudiesforinclusionandtocollectdataandassessriskofbias.Wecalculated
study-level effect sizes as standardised mean differences (SMDs) between comparison groups, measured as quantities selected or
consumed.Wecombinedtheseresultsusingrandom-effectsmeta-analysismodelstoestimatesummaryeffectsizes(SMDswith95%
confidenceintervals(CIs))foreachoutcomeforsizeandshapecomparisons.WeratedtheoverallqualityofevidenceusingtheGRADE
system.Finally,weusedmeta-regressionanalysistoinvestigatestatisticalassociationsbetweensummaryeffectsizesandvariantstudy,
interventionorparticipantcharacteristics.
Mainresults
Thecurrentversionofthisreviewincludes72studies,publishedbetween1978andJuly2013,assessedasbeingatoverallunclearor
highriskofbiaswithrespecttoselectionandconsumptionoutcomes.Ninety-sixpercentofincludedstudies(69/72)manipulated
foodproductsand4%(3/72)manipulatedcigarettes.Noincludedstudiesmanipulatedalcoholproducts.Forty-ninepercent(35/72)
manipulatedportionsize,14%(10/72)packagesizeand21%(15/72)tablewaresizeorshape.Morestudiesinvestigatedeffectsamong
adults(76%(55/72))thanchildrenandallstudieswereconductedinhigh-incomecountries-predominantlyintheUSA(81%(58/
72)).Sourcesoffundingwerereportedforthemajorityofstudies,withnoevidenceoffundingbyagencieswithpossiblecommercial
interestsintheirresults.
A meta-analysis of 86 independent comparisons from 58 studies (6603 participants) found a small to moderate effectof portion,
package,individual unitortablewaresizeonconsumptionoffood(SMD0.38,95%CI0.29to0.46),providingmoderatequality
evidencethatexposuretolargersizesincreasedquantitiesoffoodconsumedamongchildren(SMD0.21,95%CI0.10to0.31)and
adults(SMD0.46,95%CI0.40to0.52).Thesizeofthiseffectsuggeststhat,ifsustainedreductionsinexposuretolarger-sizedfood
portions,packagesandtablewarecouldbeachievedacrossthewholediet,thiscouldreduceaveragedailyenergyconsumedfromfood
bybetween144and228kcal(8.5%to13.5%fromabaselineof1689kcal)amongUKchildrenandadults.Ameta-analysisofsix
independentcomparisonsfromthreestudies(108participants)foundlowqualityevidencefornodifferenceintheeffectofcigarette
lengthonconsumption(SMD0.25,95%CI-0.14to0.65).
Oneincludedstudy(50participants)estimatedalargeeffectonconsumptionofexposuretodifferentlyshapedtableware(SMD1.17,
95%CI0.57to1.78),ratedasverylowqualityevidencethatexposuretoshorter,widerbottles(versustaller,narrowerbottles)increased
quantitiesofwaterconsumedbyyoungadultparticipants.
Ameta-analysisof13independentcomparisonsfrom10studies(1164participants)foundasmalltomoderateeffectofportionor
tablewaresizeonselectionoffood(SMD0.42,95%CI0.24to0.59),ratedasmoderatequalityevidencethatexposuretolargersizes
increasedthequantitiesoffoodpeopleselectedforsubsequentconsumption.Thiseffectwaspresentamongadults(SMD0.55,95%
CI0.35to0.75)butnotchildren(SMD0.14,95%CI-0.06to0.34).
Inaddition,ameta-analysisofthreeindependentcomparisonsfromthreestudies(232participants)foundaverylargeeffectofexposure
todifferentlyshapedtablewareonselectionofnon-alcoholicbeverages(SMD1.47,95%CI0.52to2.43),ratedaslowqualityevidence
thatexposuretoshorter,wider(versustaller,narrower)glassesorbottlesincreasedthequantitiesselectedforsubsequentconsumption
amongadults(SMD2.31,95%CI1.79to2.83)andchildren(SMD1.03,95%CI0.41to1.65).
Authors’conclusions
Thisreviewfoundthatpeopleconsistentlyconsumemorefoodanddrinkwhenofferedlarger-sizedportions,packagesortableware
thanwhen offeredsmaller-sizedversions. This suggests thatpolicies and practicesthat successfullyreduce thesize, availability and
appealoflarger-sizedportions,packages,individualunitsandtablewarecancontributetomeaningfulreductionsinthequantitiesof
food(includingnon-alcoholicbeverages)peopleselectandconsumeintheimmediateandshortterm.However,itisuncertainwhether
reducingportionsatthesmallerendofthesizerangecanbeaseffectiveinreducingfoodconsumptionasreductionsatthelargerend
oftherange.Weareunabletohighlightclearimplicationsfortobaccooralcoholpolicyduetoidentifiedgapsinthecurrentevidence
base.
Portion,packageortablewaresizeforchangingselectionandconsumptionoffood,alcoholandtobacco(Review) 2
Copyright©2017TheAuthors.CochraneDatabaseofSystematicReviewspublishedbyJohnWiley&Sons,Ltd.onbehalfofThe
CochraneCollaboration.
PLAIN LANGUAGE SUMMARY
Portion,packageortablewaresizeforchangingselectionandconsumptionoffood,alcoholandtobacco
Reviewquestion
Wereviewedtheevidencetoestablishbyhowmuchtheamountsoffood,alcoholortobaccoadultsandchildrenselectorconsume
changeinresponsetobeingpresentedwithlargerorsmaller-sized(ordifferentlyshaped)portionsorpackagesoftheseproducts,orof
itemsoftableware(suchasplatesorglasses)usedtoconsumethem.
Studycharacteristics
Thisreviewincludes72randomisedcontrolledtrials(RCTs)publisheduptoJuly2013thatcomparedatleasttwogroupsofparticipants,
eachpresentedwithadifferentsizeofaportion,packageoritemoftableware.Includedstudiesmeasuredtheamountsoffood,alcohol
or tobacco selectedand/or consumed byparticipants, typicallyover aperiod of one day or less.Almostall of theincluded studies
investigatedfood,withonlythreetobaccostudiesandnoalcoholstudiesfound.Almostallassessedparticipants’responsestodifferent
sizesratherthandifferentshapes.Theaverage ageofparticipantsinthedifferentstudiesrangedfromthreeto55years,with more
studiesinvolvingadultsthanchildrenandmostconductedintheUSA.Sourcesoffundingwerereportedforthemajorityofstudies
andtherewasnoevidenceofstudyfundingbyagencieswithcommercialinterestsintheirresults.
Keyfindingsandqualityofevidence
Effectsofsizeonconsumption:Wefoundevidencethatpeopleconsistentlyatemorefoodordrankmorenon-alcoholicdrinkswhen
offeredlarger-sizedportions,packagesoritemsoftablewarethanwhenofferedsmaller-sizedversions.Weestimatethesizeofthiseffect
tobe smallto moderate among both childrenand adults. If an effectof thissize were sustained across thewhole dietit would be
equivalenttoarounda12%to16%changeinaveragedailyenergyintakefromfoodamongUKadults.Weratedtheoverallquality
oftheevidence forthiseffectasmoderate,duetoconcernabout studylimitations arising fromincompleteor unclearreportingof
methodsandprocedures.Fromthreetobaccostudies,wefoundnoeffectoflongercomparedwithshortercigarettesontheamounts
oftobaccoconsumed.Weratedtheoverallqualityofevidenceforthiseffectaslowduetoconcernsaboutstudylimitationsandnot
havingenoughevidence.
Effectsofshapeonconsumption:Onestudyfoundthatadultsprovidedwithshorter,widerbottlesdranklargeramountsofwater
fromthem,havingalreadypouredmore,comparedwiththoseprovidedwithtaller,narrowerbottles.However,weratedthequalityof
thisevidenceasverylow,duetoveryseriousconcernsaboutstudylimitationsandnothavingenoughevidence(onlyonestudywith
outcomedatafrom50participants).
Effectsofsizeonselection:Wefurtherfoundthatadults,butnotchildren,consistentlychose(selected)morefood(includingnon-
alcoholic drinks) when offered larger-sized portions, packages or items of tableware than when offered smaller-sizedversions. The
estimatedsizeofthiseffectwasagainsmalltomoderate.Weratedtheoverallqualityoftheevidenceforthiseffectasmoderate,dueto
concernaboutstudylimitations.
Effectsofshapeonselection:Evidencefromthreestudiessuggestedthatadultsandchildrenprovidedwithshorter,widerbottlesor
glassesselectedincreasedquantitiesofnon-alcoholicbeveragesforsubsequentconsumption,comparedwiththoseprovidedwithtaller,
narrowerbottlesorglasses.Weratedthequalityofthisevidenceaslow,againduetoconcernsaboutstudylimitationsandunexplained
variationineffectsbetweenthethreestudies.
Conclusions
Overall,thisreviewprovidesthemostconclusiveevidencetodatethatactingtoreducethesize,availabilityandappealoflarger-sized
portions,packagesandtablewarehaspotentialtoreducethequantitiesoffoodthatpeopleselectandconsumebymeaningfulamounts.
However,itisuncertainwhetherreducingportionsatthesmallerendofthesizerangecanbeaseffectiveinreducingfoodconsumption
asreductionsatthelargerendoftherange.Ourfindingshighlighttheneedforfurtherresearchthataimstoreduceuncertaintiesabout
theseeffectsandaddressidentifiedgapsintheevidencebase,includingnothavingenoughevidenceforlonger-termeffectsandthe
absenceofevidenceaboutalcoholproducts.
Portion,packageortablewaresizeforchangingselectionandconsumptionoffood,alcoholandtobacco(Review) 3
Copyright©2017TheAuthors.CochraneDatabaseofSystematicReviewspublishedbyJohnWiley&Sons,Ltd.onbehalfofThe
CochraneCollaboration.
CochraneCCopyright©Portion,pac SUMMARY OF FINDINGS FOR THE MAIN COMPARISON [Explanation]
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BACKGROUND mosthumanbehaviouroccursoutsideofawareness,cuedbystim-
uliinenvironmentsandresultinginactionsthatmaybelargelyun-
accompaniedbyconsciousreflection(Marteau2012;Neal2006).
Thispropositionhasledtoincreasingpolicyandresearchatten-
Descriptionofthecondition
tionbeingplacedoninterventionswithmechanismsofactionthat
Non-communicable diseases, principally cardiovascular diseases, arelessdependentontheconsciousengagementoftherecipients,
diabetes,certainformsofcancerandchronicrespiratorydiseases, includinginterventionsthatinvolvealteringpropertiesofobjects
accountedforanestimated62%ofalldeathsworldwidein2012 orstimuliwithinthesmall-scaleenvironmentsthatsurroundand
(World Health Organization 2014a), and globally the propor- cuebehaviour(Hollands2013a).
tionofyearsoflifelostasaresultofnon-communicablediseases Anumberofmechanismsofactionhavebeenproposedtoexplain
increased from 38% in 2000 to 47% in 2012 (World Health howthesizeofproductsmayaffecttheirconsumption(Herman
Organization2014b).Majorriskfactorsfortheseconditionsare 2015;Steenhuis2009).Ithasbeensuggestedthatastheamount
inpartdeterminedbypatternsofbehaviourthatareinprinciple ofaproductmadeavailableforconsumptionisincreased,individ-
modifiable,includingconsumptionoffood,alcoholandtobacco ualswillcontinuetoperceiveeachincreasingamountasanappro-
products (United Nations 2014). Identifying interventions that priatequantitytoconsume.Thisphenomenonmaybeexplained
are effectiveinachieving sustained healthbehaviour change has byseveralmediatingfactorsincludingpersonalandsocialnorms
thereforebecomeoneofthemostimportantpublichealthchal- aboutwhatconstitutesasuitableamountofaproducttoconsume.
lengesofthe21st century. Suchnormscanbeinfluencedbytheamountsthatarepresented
for consumption, and larger portions of food have become in-
creasinglyprevalent,makingitincreasinglyunlikelythatsmaller
Descriptionoftheintervention portionsareviewedasnormalorappropriateforasingleserving
(Young2002).Thereisalsoatendencyforindividualstoengage
Itisincreasingly recognisedthatthephysicalenvironmentsthat mostcomfortablywithaproductasasingleentityindependentof
surrounduscanexertconsiderable influencesonour healthbe- itssize.This’unitbias’meansthattheyarepredisposedtoconsume
haviourandthatalteringtheseenvironmentsmayprovideacat- theentiretyofaproductevenasitchangessize(Geier2006).In
alyst for behaviour change (Das 2012). In a recent scoping re- addition,thewayinwhichproductsarepresentedcaninfluence
view, we described a class of interventions that involve altering theirconsumption.Thepresentationoffoodandalcoholproducts
the propertiesor placementof objects or stimuli within micro- oftenentailstheuseoftableware,suchasplates,glassesorcutlery.
environmentssuchasshops,restaurants,barsorhomes,withthe Notonlydoesthesizeoftablewarehavethepotentialtodirectlyin-
intentionofchanginghealth-relatedbehaviours(Hollands2013a; fluencetheamountofaproductavailableforconsumption(Pratt
Hollands2013b). 2012),butitsphysicaldimensionscanelicitvariouscognitivebi-
Thesizeofaportionorpackageisamodifiablepropertyoffood, ases(Wansink2005),whichmayinfluenceperceptionsofquan-
alcoholandtobacco productsthatmay influence theirselection tityandinturndeterminelevelsofconsumption.Similarly,sub-
andconsumption. Inthecaseoffoodandalcoholproducts,the dividingafixedportionofafoodintosmallerpiecesalsoaffects
sizeorshapeofanitemoftablewareusedtoconsumesuchprod- perceptions of quantity (Scisco 2012). All of these mechanisms
uctsmaysimilarlyinfluencetheirselectionandconsumption.Ex- may also influence product selection (with or without purchas-
amplesinclude the portion size of alcoholicbeveragesservedin ing),whichisanimportantintermediateoutcomeinpathwaysto
barsoroffoodsservedinrestaurants,atabuffetorinthehome, consumption.
suchasportionsofadishservedtorestaurantcustomers(Diliberti Extantresearchinvolvingtheexperimentalmanipulationofpor-
2004),thesizeorshapeofplatesorglassesusedtoserveproducts tion,packageortablewaresizehasfocusedonfood(includingnon-
(Shah2011), andthenumber or length of cigarettesin packets alcoholicbeverage)productstoamuchgreaterextentthantobacco
soldinshops(Russell1980).Inthiscontext,theinterventionin- products(Hollands2013a).Whilstthecausalmechanismsofun-
volvesmanipulationofthesizeorphysicaldimensionsofafood, derlying potential effectsof such manipulations on selection or
alcoholortobaccoproduct,itspackagingorthetablewareusedin consumptionoftobaccomaybeassumedtobebroadlysimilarto
itsconsumption. Comparisonsofinterestarebetweenproducts, food,smokersareknowntotitratetheirreceiveddoseofnicotine
packagesoritemsoftableware thatdifferonlyintermsofthese toregulatethelevelinthebody,withthepotentialtoattenuate
properties. theeffectsof interventions to alterthe size of tobacco products
(Kozlowski1986).
Howtheinterventionmightwork
Thereare considerable influences onbehaviour thatarebeyond
Whyitisimportanttodothisreview
individuals’deliberativecontrol.Indeed,ithasbeensuggestedthat
Portion,packageortablewaresizeforchangingselectionandconsumptionoffood,alcoholandtobacco(Review) 7
Copyright©2017TheAuthors.CochraneDatabaseofSystematicReviewspublishedbyJohnWiley&Sons,Ltd.onbehalfofThe
CochraneCollaboration.
Arecentscopingreview ofevidencefortheeffectsofchoicear- impactofsuchpolicies.
chitecture interventions identified a substantial number of ran-
domisedcontrolledtrialsthathaveinvestigatedtheeffectsofex-
posuretodifferentportion,packageortablewaresizesonselection
andconsumptionbehaviours(Hollands2013a).Themajorityof
OBJECTIVES
thesestudiesfocusedonfoodproducts,butbecausebothtobacco
and alcohol use also involve the selection and consumption of
1. Toassesstheeffectsofinterventionsinvolvingexposureto
products,similarinterventionsmayhavethepotentialtochange
differentsizesorsetsofphysicaldimensionsofaportion,
thesebehavioursviasimilarmechanisms.Toourknowledge,evi-
package,individualunitoritemoftablewareonunregulated(ad
dencefromthesestudieshasyettobesynthesisedusingrigorous
libitum)selectionorconsumptionoffood,alcoholortobacco
systematicreviewmethodsthatincludeassessmentofriskofbias
productsinadultsandchildren.
andinvestigationofpotentialeffectmodifiers,nortoencompass
alcoholandtobaccouse.Assuch,wedonotyethavereliablees- 2. Toassesstheextenttowhichtheeffectsofsuch
timates of the effects of altering the sizes of portions, packages interventionsmaybemodifiedby:
or tableware onproduct selectionand consumption, nor of the
influence of factors thatmay modify any such effects. Both are i) studycharacteristics,suchastargetproducttype(food,
necessary to inform the selection and design of effective public alcohol,tobacco)orwhetherthetargetofthemanipulationisa
healthinterventions. portion,package,individualunitoritemoftableware;
Interventions that aim to reduce people’s exposure to larger or
ii) interventioncharacteristics,suchasmagnitudeofthe
smallerfoodportions,asopposedtothosethatinvolveproviding
differenceinsize;and
informationtoencouragehealthbehaviourchange,mayalsohave
thepotentialtoreducehealthinequalitiesiftheyrelylessonre- iii) participantcharacteristics,suchasage,genderor
cipients’levelsofliteracy,numeracyandcognitivecontrol,which socioeconomicstatus(tofacilitateanassessmentofsocial
havebeenfoundtobelowerinpopulationsubgroupsexperienc- differentiationineffectsrelevanttohealthequity).
inghigherlevelsofsocialandmaterialdeprivation(Kutner2006;
Marteau 2012; Spears 2010; Williams 2003). Despite evidence
thatbehaviourswiththepotentialtounderminehealtharesocially METHODS
patterned(forexample,thatpeopleinlowersocioeconomicgroups
tendtoconsumelessfruitandvegetables(Giskes2010)),potential
differences in behavioural responses to product sizing interven-
Criteriaforconsideringstudiesforthisreview
tionsbetweensocioeconomicsubgroupsremainunclear.Also,to
ourknowledge(priortoconductingthisreview),nostudiesofthe
effectsofproductsizehadbeenconductedinlowormiddle-in-
Typesofstudies
come(LMIC)countrypopulations(Hollands2013a).Thisreview
thereforeincludesafocusonidentifyingevidencefordifferential Randomised controlled trials with between-subjects (parallel-
effectsofexposuretodifferentsizesoftheseproductsbetweenso- group)orwithin-subjects(cross-over)designs,conductedinlabo-
cioeconomicsubgroups(andbetweenstudiesconductedinLMIC ratoryorfieldsettings.Weexcludednon-randomisedstudiesbe-
andhigh-incomecountries(HIC)),highlightanyidentifiedgaps causeourrecentscopingreviewindicatedthatasufficientnum-
inthisaspectoftheevidencebase,andseektodrawimplications berofeligiblerandomisedcontrolledtrialswouldbeavailableto
forthepotentialofsuchinterventionstoaffecthealthinequalities. address our aim to synthesise evidence for intervention effects
Thissystematicreviewisalsotimelygivencurrentinterestinthe (Hollands2013a).Akeyissueisthat,comparedwithrandomised
topicwithinpublichealthpolicycircles.Thereisevidencefrom controlledtrials,non-randomisedstudiesrelyonmorestringent
theUSAandEuropethatportionsizeshavebeenincreasingsince andsometimesnon-verifiableassumptionsinordertoconfercon-
the1970s (Young2002;Young2012).Therehavealsobeenre- fidencethat,withsuccessfulimplementationofthestudydesign,
centattemptstoregulatethesizeofproductsinordertoreduce theriskofsystematicdifferencesbetweencomparisongroupsbe-
consumptionlevelsandimprovepublichealth,suchasNewYork yondtheinterventionofinterest(i.e.confounding)issufficiently
CityMayorMichaelBloomberg’sproposedbanonthesaleofsug- lowtopermitvalidinferencesaboutcausaleffects.
arydrinkslargerthan16oz(473ml)(Gabbatt2013).IntheUK,
therearerecentexamplesofcompaniesreducingtheportionsizes
Typesofparticipants
of confectionery and sugary drinks aspartof thePublicHealth
Adultsandchildrendirectlyengagedwiththemanipulatedprod-
ResponsibilityDealinEngland.Thissystematicreviewcancon-
ucts.Wesetnoexclusioncriteriainrelationtodemographic,so-
tributetoabetterevidence-basedunderstandingofthepotential
cioeconomic or clinicalcharacteristicsor prognostic factors.We
Portion,packageortablewaresizeforchangingselectionandconsumptionoffood,alcoholandtobacco(Review) 8
Copyright©2017TheAuthors.CochraneDatabaseofSystematicReviewspublishedbyJohnWiley&Sons,Ltd.onbehalfofThe
CochraneCollaboration.