Does intermittent fastingwork?间歇性禁食有效吗？Itdoesforweightloss.Itsothersupposedbenefitsaredebatable对于减肥确实有效。但其宣称的其他健康效益仍有争议Dietscomeanddietsgo.Oneofthemostpopulartodayis “intermittentfasting” inwhich,asthenamesuggests,theideaistolimitone’sfoodintaketocertaintimewindows.Onepopular variant,the “5-2diet”,requirespeopletoeateitherverysmallamounts,ornothingatall,ontwodaysaweek,butimposesnorestrictionsontheotherfive.减肥方法层出不穷。时下最流行的当属"间歇性禁食"——顾名思义，就是将进食时间限定在特定时段。其中"5-2轻断食法"颇受欢迎，要求每周两天仅少量进食或完全禁食，其余五天则无需限制。Intermittentfastingispopular.Andasaweight-lossstrategy,ithasseveralthingsgoingforit.Oneisthatitisuncomplicated.Thereisnoneedtoweightheingredientsofeverymeal,assomedietsdemand,nortochangewhatyoueat drastically.Limitingtherestrictionstoacoupleofdaysaweek,orseveralhoursaday(mostofwhicharespentasleep)alsorequiresless willpower,whichmightmakeiteasiertostickwith.这种饮食方式大行其道。作为减重策略，它具备多项优势。其一，操作简单。无需像某些饮食法那样精确称量每餐食材，也无需彻底改变饮食结构。每周仅需坚持数天，或每天限制数小时（大部分时间在睡眠中度过），意志力的消耗相对较少，因此更易长期坚持。Workingoutwhetherthatactuallytranslatesintogreaterweightlossthanotherdietsisdifficult.Moststudiesfindlimiteddataandmixedresults.Thegeneralconsensus,saysNicholaLudlam-Raine,adietitianandspokeswomanfortheBritishDieteticAssociation,isthatintermittentfastingseemstoworkroughlyaswellforweightlossastraditionalcalorie-countingdoes.但要验证其减重效果是否优于其他饮食法却非易事。多数研究数据有限且结果不一。英国饮食协会发言人、营养学家尼古拉·拉德拉姆-雷恩指出，学界普遍认为间歇性禁食与传统热量控制法在减重效果上大致相当。Otherhealthbenefitsmightalsobeckon.Forcinglabanimalstofast(albeitnotintermittently)canincreasetheirlifespansbyupto40%.Italsoappearsto mitigate thephysicaldeclinethatcomeswitholdage,boostvariousmarkersofmetabolichealthandevenreducesusceptibilitytocancer.该饮食法可能还具备其他健康裨益。实验室动物强制禁食（尽管不是间歇性禁食）可延长寿命达40%，同时能延缓机体衰老、改善代谢指标，甚至降低患癌风险。Exactlyhowitdoesallthatisnotentirelyclear.Oneimportantfactorseemstobeautophagy,theprocessbywhichcellsbreakdownandrecyclepartsofthemselves.Cellsbecomemuchkeeneronautophagywhennutrientsarescarce. 具体作用机制尚未完全阐明。一个重要因素可能是细胞自噬机制——即细胞分解并回收自身部分结构的过程。当营养匮乏时，细胞自噬活动显著增强。Atthesametime,autophagyseemstohaveapreferenceforattackingdamagedanddegradedpartsofcells—andtheaccumulationofsuchcellulardetritusisoneofseveralmechanismsthoughttounderliethe decrepitude thatcomeswithageing.同时，这种机制优先清除细胞内的受损老化部分，而此类细胞碎片的堆积正是导致衰老的重要因素。Thehopeisthatintermittentfastingmightprovokeasimilarresponseinhumans.Therearetheoreticalreasonstothinkitmight:thecellularmechanismstriggeredbyfoodshortagesseemtohavebeenconservedbyevolutioninallsortsofdifferentanimals. 人们期待间歇性禁食能在人体引发类似反应。从理论上讲确有可能：食物短缺引发的细胞机制似乎已在各类动物中进化保留。Butrunningdefinitivehumantrialsofthesortdoneonlabanimalsisimpossible.“Whenwesay ‘calorierestriction’ wemeannearlystarving[theanimals],”saysAdamCollins,anutritionresearcherattheUniversityofSurrey.但要在人体开展实验室动物那种严格试验并不可行。萨里大学营养学家亚当·柯林斯指出："我们所说的'热量限制'对实验动物而言近乎饥饿疗法。"Thatleavesscientistsreliant,fornow,onsmallish,short-livedstudiesthatuselessdrasticdietsandwhichrelyon proxy measuresofhealthsuchasinsulinresponseorcholesterollevels.Theirresultsaremixed. 目前科学家只能依赖规模较小、周期较短的替代性研究，这些研究采用较温和的饮食方案，并以胰岛素反应或胆固醇水平等替代指标评估健康效益。研究结果同样存在分歧。DrCollins’steam,forinstance,haspublishedarandomised-controltrial(themostrigoroussort)suggestingthatintermittentfastingimprovesthemetabolismoffatsmorethanordinarydietingdoes. 柯林斯博士团队发表的随机对照试验（最严谨的研究类型）显示，间歇性禁食比普通节食更能改善脂肪代谢。AreviewpaperpublishedinApril2024lookedat23otherstudiesandconcludedthatintermittentfastingwasslightlybetterthanordinarydietingforoverweightpeoplewhenitcametoimprovinglevelsofcholesterolandinsulin.Asimilararticle,publishedinJanuary,foundnomeaningfuldifferenceforeitherweightlossorcardiovascularhealth.2024年4月发表的一篇综述对23项研究进行分析后认为，在改善超重人群胆固醇和胰岛素水平方面，间歇性禁食略胜一筹；但同年1月的另一篇类似论文发现，在减重效果和心血管健康方面两者并无显著差异。Therearealsorisks.AstudyinmicepublishedinNatureinOctober2024foundthatseverefasting(wherecalorieswerecutby40%)haddownsides,includingmusclemasslossand,possibly,weakenedimmunesystems.Moderation,too,shouldbetakeninmoderation.潜在风险亦不容忽视。2024年10月《自然》杂志刊登的一项小鼠实验表明，严格禁食（热量摄入减少40%）会导致肌肉流失，并可能削弱免疫系统。适度原则本身也需把握分寸。（红色标注词为重难点词汇）重难点词汇：intermittent [ˌɪntərˈmɪtənt]adj. 间歇的；断断续续的variant [ˈveəriənt]n. 变体；变种 adj.不同的；变化的drastically [ˈdræstɪkəli]adv. 彻底地；激烈地；极大地willpower [ˈwɪlpaʊər]n. 意志力；毅力mitigate [ˈmɪtɪɡeɪt]v. 减轻；缓和；缓解decrepitude [dɪˈkrepɪtjuːd]n. 衰老；虚弱；老朽proxy [ˈprɒksi]n. 代理；代表；代理人 v. 代理；代表
