Glycemic index diet: What's behind the claims - Mayo Clinic

The glycemic index is a system of assigning a number to carbohydrate-containing foods according to how much each food increases blood sugar. COVID-19:Advice,updatesandvaccineoptions Weareopenforsafein-personcare. Learnmore: MayoClinicfactsaboutcoronavirusdisease2019(COVID-19) OurCOVID-19patientandvisitorguidelines,plustrustedhealthinformation Lateston COVID-19vaccination bysite: Arizonapatientvaccinationupdates Arizona, Floridapatientvaccinationupdates Florida, Rochesterpatientvaccinationupdates Rochesterand MayoClinicHealthSystempatientvaccinationupdates MCHS Skiptositenavigation SkiptoContent ThiscontentdoesnothaveanEnglishversion. ThiscontentdoesnothaveanArabicversion. 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Theglycemicindexisasystemofassigninganumbertocarbohydrate-containingfoodsaccordingtohowmucheachfoodincreasesbloodsugar.Theglycemicindexitselfisnotadietplanbutoneofvarioustools—suchascaloriecountingorcarbohydratecounting—forguidingfoodchoices. Theterm"glycemicindexdiet"usuallyreferstoaspecificdietplanthatusestheindexastheprimaryoronlyguideformealplanning.Unlikesomeotherplans,aglycemicindexdietdoesn'tnecessarilyspecifyportionsizesortheoptimalnumberofcalories,carbohydrates,orfatsforweightlossorweightmaintenance. Manypopularcommercialdiets,dietbooksanddietwebsitesarebasedontheglycemicindex,includingtheZoneDiet,SugarBustersandtheSlow-CarbDiet. Purpose Thepurposeofaglycemicindex(GI)dietistoeatcarbohydrate-containingfoodsthatarelesslikelytocauselargeincreasesinbloodsugarlevels.Thedietcouldbeameanstoloseweightandpreventchronicdiseasesrelatedtoobesitysuchasdiabetesandcardiovasculardisease. WhyyoumightfollowtheGIdiet YoumightchoosetofollowtheGIdietbecauseyou: Wanttoloseweightormaintainahealthyweight Needhelpplanningandeatinghealthiermeals Needhelpmaintainingbloodsugarlevelsaspartofadiabetestreatmentplan StudiessuggestthataGIdietcanhelpachievethesegoals.However,youmightbeabletoachievethesamehealthbenefitsbyeatingahealthydiet,maintainingahealthyweightandgettingenoughexercise. Checkwithyourdoctororhealthcareproviderbeforestartinganyweight-lossdiet,especiallyifyouhaveanyhealthconditions,includingdiabetes. Theglycemicindex TheGIprinciplewasfirstdevelopedasastrategyforguidingfoodchoicesforpeoplewithdiabetes.AninternationalGIdatabaseismaintainedbySydneyUniversityGlycemicIndexResearchServicesinSydney,Australia.Thedatabasecontainstheresultsofstudiesconductedthereandatotherresearchfacilitiesaroundtheworld. Abasicoverviewofcarbohydrates,bloodsugarandGIvaluesishelpfulforunderstandingglycemicindexdiets. Carbohydrates Carbohydrates,orcarbs,areatypeofnutrientinfoods.Thethreebasicformsaresugars,starchesandfiber.Whenyoueatordrinksomethingwithcarbs,yourbodybreaksdownthesugarsandstarchesintoatypeofsugarcalledglucose,themainsourceofenergyforcellsinyourbody.Fiberpassesthroughyourbodyundigested. Twomainhormonesfromyourpancreashelpregulateglucoseinyourbloodstream.Thehormoneinsulinmovesglucosefromyourbloodintoyourcells.Thehormoneglucagonhelpsreleaseglucosestoredinyourliverwhenyourbloodsugar(bloodglucose)levelislow.Thisprocesshelpskeepyourbodyfueledandensuresanaturalbalanceinbloodglucose. Differenttypesofcarbohydratefoodshavepropertiesthataffecthowquicklyyourbodydigeststhemandhowquicklyglucoseentersyourbloodstream. UnderstandingGIvalues TherearevariousresearchmethodsforassigningaGIvaluetofood.Ingeneral,thenumberisbasedonhowmuchafooditemraisesbloodglucoselevelscomparedwithhowmuchpureglucoseraisesbloodglucose.GIvaluesaregenerallydividedintothreecategories: LowGI:1to55 MediumGI:56to69 HighGI:70andhigher Comparingthesevalues,therefore,canhelpguidehealthierfoodchoices.Forexample,anEnglishmuffinmadewithwhitewheatflourhasaGIvalueof77.Awhole-wheatEnglishmuffinhasaGIvalueof45. LimitationsofGIvalues OnelimitationofGIvaluesisthattheydon'treflectthelikelyquantityyouwouldeatofaparticularfood. Forexample,watermelonhasaGIvalueof80,whichwouldputitinthecategoryoffoodtoavoid.Butwatermelonhasrelativelyfewdigestiblecarbohydratesinatypicalserving.Inotherwords,youhavetoeatalotofwatermelontosignificantlyraiseyourbloodglucoselevel. Toaddressthisproblem,researchershavedevelopedtheideaofglycemicload(GL),anumericalvaluethatindicatesthechangeinbloodglucoselevelswhenyoueatatypicalservingofthefood.Forexample,a4.2-ounce(120-gram,or3/4-cup)servingofwatermelonhasaGLvalueof5,whichwouldidentifyitasahealthyfoodchoice.Forcomparison,a2.8-ounce(80-gram,or2/3-cup)servingofrawcarrotshasaGLvalueof2. SydneyUniversity'stableofGIvaluesalsoincludesGLvalues.Thevaluesaregenerallygroupedinthefollowingmanner: LowGL:1to10 MediumGL:11to19 HighGL:20ormore Otherissues AGIvaluetellsusnothingaboutothernutritionalinformation.Forexample,wholemilkhasaGIvalueof31andaGLvalueof4fora1-cup(250-milliliter)serving.Butbecauseofitshighfatcontent,wholemilkisnotthebestchoiceforweightlossorweightcontrol. ThepublishedGIdatabaseisnotanexhaustivelistoffoods,butalistofthosefoodsthathavebeenstudied.ManyhealthyfoodswithlowGIvaluesarenotinthedatabase. TheGIvalueofanyfooditemisaffectedbyseveralfactors,includinghowthefoodisprepared,howitisprocessedandwhatotherfoodsareeatenatthesametime. Also,therecanbearangeinGIvaluesforthesamefoods,andsomewouldargueitmakesitanunreliableguidetodeterminefoodchoices. Dietdetails AGIdietprescribesmealsprimarilyoffoodsthathavelowvalues.Examplesoffoodswithlow,middleandhighGIvaluesincludethefollowing: LowGI:Greenvegetables,mostfruits,rawcarrots,kidneybeans,chickpeas,lentilsandbranbreakfastcereals MediumGI:Sweetcorn,bananas,rawpineapple,raisins,oatbreakfastcereals,andmultigrain,oatbranorryebread HighGI:Whiterice,whitebreadandpotatoes CommercialGIdietsmaydescribefoodsashavingslowcarbsorfastcarbs.Ingeneral,foodswithalowGIvaluearedigestedandabsorbedrelativelyslowly,andthosewithhighvaluesareabsorbedquickly. CommercialGIdietshavevaryingrecommendationsforportionsize,aswellasproteinandfatconsumption. Results Dependingonyourhealthgoals,studiesofthebenefitsofGIdietshaveproducedmixedresults. Weightloss Resultsofa16-yearstudythattrackedthedietsof120,000menandwomenwerepublishedin2015.ResearchersfoundthatdietswithahighGLfromeatingrefinedgrains,starchesandsugarswereassociatedwithmoreweightgain. OtherstudiesshowthatalowGIdietmayalsopromoteweightlossandhelpmaintainweightloss.However,datafromanotherstudyindicatedasubstantialrangeinindividualGIvaluesforthesamefoods.ThisrangeofvariabilityinGIvaluesmakesforanunreliableguidewhendeterminingfoodchoices. Bloodglucosecontrol Studiesshowthatthetotalamountofcarbohydrateinfoodisgenerallyastronger predictorofbloodglucoseresponsethantheGI.Basedontheresearch,formostpeoplewithdiabetes,thebesttoolformanagingbloodglucoseiscarbohydratecounting. Someclinicalstudieshaveshownthatalow-GIdietmayhelppeoplewithdiabetescontrolbloodglucoselevels,althoughtheobservedeffectsmayalsobeattributedtothelow-calorie,high-fibercontentofthedietsprescribedinthestudy. Cholesterol Reviewsoftrialsmeasuringtheimpactoflow-GIindexdietsoncholesterolhaveshownfairlyconsistentevidencethatsuchdietsmayhelplowertotalcholesterol,aswellaslow-densitylipoproteins(the"bad"cholesterol)—especiallywhenalow-GIdietiscombinedwithanincreaseindietaryfiber.Low-tomoderate-GIfoodssuchasfruits,vegetablesandwholegrainsaregenerallygoodsourcesoffiber. Appetitecontrol Onetheoryabouttheeffectofalow-GIdietisappetitecontrol.Thethinkingisthathigh-GIfoodcausesarapidincreaseinbloodglucose,arapidinsulinresponseandasubsequentrapidreturntofeelinghungry.Low-GIfoodswould,inturn,delayfeelingsofhunger.Clinicalinvestigationsofthistheoryhaveproducedmixedresults. Also,ifalow-GIdietsuppressesappetite,thelong-termeffectshouldbethatsuchadietwouldresultoverthelongterminpeoplechoosingtoeatlessandbettermanagetheirweight.Thelong-termclinicalresearchdoesnot,however,demonstratethiseffect. Thebottomline Inorderforyoutomaintainyourcurrentweight,youneedtoburnasmanycaloriesasyouconsume.Toloseweight,youneedtoburnmorecaloriesthanyouconsume.Weightlossisbestdonewithacombinationofreducingcaloriesinyourdietandincreasingyourphysicalactivityandexercise. Selectingfoodsbasedonaglycemicindexorglycemicloadvaluemayhelpyoumanageyourweightbecausemanyfoodsthatshouldbeincludedinawell-balanced,low-fat,healthydietwithminimallyprocessedfoods—whole-grainproducts,fruits,vegetablesandlow-fatdairyproducts—havelow-GIvalues. Forsomepeople,acommerciallow-GIdietmayprovideneededdirectiontohelpthemmakebetterchoicesforahealthydietplan.TheresearcherswhomaintaintheGIdatabasecaution,however,thatthe"glycemicindexshouldnotbeusedinisolation"andthatothernutritionalfactors—calories,fat,fiber,vitaminsandothernutrients—shouldbeconsidered.   Thereisaproblemwith informationsubmittedforthisrequest.Review/updatethe informationhighlightedbelowandresubmittheform. GetthelatesthealthinformationfromMayoClinic’sexperts. 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Sorrysomethingwentwrongwithyoursubscription Please,tryagaininacoupleofminutes Retry ShareTweet Aug.25,2020 Showreferences AugustinLSA,etal.Glycemicindex,glycemicloadandglycemicresponse:AnInternationalScientificConsensusSummitfromtheInternationalCarbohydrateQualityConsortium(ICQC).Nutrition,Metabolism&CardiovascularDiseases.2015;25:795. MatthanNR,etal.Estimatingthereliabilityofglycemicindexvaluesandpotentialsourcesofmethodologicalandbiologicalvariability.AmericanJournalofClinicalNutrition.2016;104:1004. Bosy-WestphalA,etal.Impactofcarbohydratesonweightregain.CurrentOpinioninClinicalNutritionandMetabolicCare.2015;18:389. LiuS,etal.Dietarycarbohydrates.https://www.uptodate.com/home.AccessedMay27,2017. GIfoodsadvancedsearch.TheUniversityofSydney.http://www.glycemicindex.com/foodSearch.php.AccessedMay27,2017. Glycemicindexanddiabetes.AmericanDiabetesAssociation.http://www.diabetes.org/food-and-fitness/food/what-can-i-eat/understanding-carbohydrates/glycemic-index-and-diabetes.html.AccessedMay27,2017. Glycemicload.GlycemicIndexFoundation.http://www.gisymbol.com/about/glycemic-load/.AccessedMay27,2017. Frequentlyaskedquestions.TheUniversityofSydney.http://www.glycemicindex.com/faqsList.php.AccessedMay27,2017. SunFH,etal.Effectofglycemicindexofbreakfastonenergyintakeatsubsequentmealamonghealthypeople:Ameta-analysis.Nutrients.2016;8:37. DietaryguidelinesforAmericans,2015-2020.U.S.DepartmentofHealthandHumanServices.https://health.gov/dietaryguidelines/.AccessedMay28,2017. SmithJD,etal.Changesinintakeofproteinfoods,carbohydrateamountandquality,andlong-termweightchange:Resultsfrom3prospectivecohorts.AmericanJournalofClinicalNutrition.2015;101:1216. ZeratskyKA(expertopinion).MayoClinic,Rochester,Minn.June9,2017. RoderPV,etal.Pancreaticregulationofglucosehomeostasis.ExperimentalandMolecularMedicine.2016;48:e219. 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