Environrnental and lifestyle factors, including diet, pray be responsible for the recognised worldwide variation in tire incidence of specific types or cancer. Chemical carcinogenesis is a multistage process occurring over a relatively long period or time. The mechanisms are complex as different factors damage develops following exposure to carcinogenic agents. Progression to malignancy is, at this stage, not inevitable. Specific agents are needed to 'promote', and induce 'progression' or inhibit subsequent changes to develop invasive malignancy. Understanding the roles played by different agents and mechanisms in the overall carcinogenic process For cc specific cancer nary form the basis for risk assessment and eventual prevention. The multistep process of carcinogenesis including initiation, promotion, and progression, are all needed for clinically invasive cancer to develop. Efforts directed to any of these phases can prevent the development of cancer.A variety of carcinogenic and mutagenic substances ore present in our diet. Some are found naturally in the food ingredients, whereas others result from pesticide residues, environmental pollution, food additives, preparation and processing procedures, curd fungal contamination. The control of these factors may render some cancers potentially avoidable.The role of macro and micro-nutrients in the causation of cancer and eventually in its prevention is complicated by their combined distribution in food products. Intensive research into the nature of cancer prevention by nutrient components and their synthetic analogs is still in its infancy. As cancer induction, promotion and progression is a slow mechanism that could take many years, it is uncertain what time-period of dietary intake is most relevant. Currently, recommended prevention strategies include choose more/choose less approach, through emphasizing a shift away from high fat, low-fiber foods that may increase cancer risks, toward foods low in fat and rich in fiber and nutrients.