Obesity, type 2 diabetes mellitus,hypertension, and coronary heart disease are serious diseases affecting asignificantnumberofadults across the globe. Insulin resistance, low-grade systemic inflammation, low-birth weight,maternalproteinmalnutrition,neonatalhighcarbohydratediet,and high fat diet are associated with these diseases. On the other hand, adequatelybreast-fedsubjects are substantially at lowerrisk. Ifso,whatis the linkbetweenthese variousfactors?Onepossibilityisthat humanbreast milk containsfactorsthatconferresistancetothese modemdiseases.Here I present arguments that long-chain polyunsaturated fatty acids (LCPUFAs) presentinthebreastmilkcouldberesponsibleforthisbeneficialaction. Though the entire class of LCPUFAs provided dunng perinatal periodislikelytohavearole inthepreventionofadultdiseases,itshouldbe understoodthateachofthese LCPUFAsexhibitauniqueand insome cases opposing bioactive properties.It is important to note that there is a close interaction between (0-6 and (0-3 fatty acids. Human breast rmlk contains almost twice (0.78 vs 0.4 3 %w/w)the amountof(0-6LCPUFAs (gamma- linolenic acid, dihomo-gamma-linolenic acid and arachidonic acid) comparedto (0-3LCPUFAs(eicosapentaenoicacid,docosapentaenoicacid, and docosahexaenoic acid). Obviously, the best would be to mimic the composition/concentrations in which these fatty acids are present in the breastmilk. The conceptthat LCPUFAs given duringpennatalperiod(and inadultlife)isbeneficialinpreventingadultdiseasescertainlyneedsfurther exploration.Iamconfidentthat someofthe enterprisingreaderswill delve intothepossibilitiessuggestedafterreadingthisbook. UndurtiN.Das,M.D.,FAMS. To MyWifeLakshmi and Mytwoeyes DaughterArundhatiandSonAditya Chapter #1 Introduction Fetal/Perinatalimprintingonlaterlife It isbelievedthat stimuliormsults during criticalorsensitiveperiods inearlylifecanhave lifetimeconsequences.Thisconceptiswellestablished in developmental biology and has been termed "programming". The evidence for programming confirmed the critical period for imprinting in animals, more so in birds'. Programming stimuli may be generated endogenously, such as hormonal signals', or they may be environmental.