1960年以後，美國速食產業改變了美國人的生活型態和飲食習慣；同時肥胖危機卻也圍繞著美國人的生活。近十年來，學者專家和美國社會開始對速食是否造成美國人普遍肥胖產生爭議。速食產業因應汽車量產和加工食品產業的相得益彰，改變美國的飲食習慣。速食飲食減少備餐時間且便宜廣為忙碌的現代美國人所喜愛。速食產業得以規模化經濟除了量產和媒體行銷外，也在學校教育下功夫並且影響政府施政。雖然速食產業幫助美國各公私立學校教育活動，但是營養午餐速食化卻也影響學生飲食習慣的養成。當速食產業推出「超大尺碼」行銷策略讓美國人增加了飲食份量，卻也逐漸延伸到和身體有關的尺寸如衣服、鞋子、家具等等。最重要的，肥胖不再只是基因問題更是與環境息息相關的問題。本論文除了探討速食產業的崛起和對美國生活飲食習慣的影響外，並檢視美國人肥胖的情形和肥胖所延伸的疾病。最後針對速食造成的肥胖爭議作研究討論，期許國內外都能正視國人健康攸關一個的國家的競爭力，唯有健康概念的建立才能在速食產業和消費者間追求雙贏。 During 1960-1970, American fast-food industry comes out and influences American lifestyle and dietary habit; meanwhile, obese crisis occurs on their surrounding. Recent decade, experts and people in America think about this controversial issue of obesity and fast food related. Automobile industry and food-processing industry provide a well-endowed environment for new fast-food industry. Fast food regarded as the prepared food shortens the time of meal preparing and is so popular in the United States. Thanks for technology, large scale economy development of fast food industry is resulted from media marketing and mass production. Besides, fast-food industry sponsors school education programs, and impacts decision making of government with lobbying. Although fast-food industry offers financial donations for private and public schools in the United States, it influences more children dietary habit by lunch contracting and vending machine. “Supersize” is a well-known marketing strategy in fast-food restaurants that you buy more and save more. Thus, American people get used to eating a large portion. The supersize of body extends from their clothes, shoes, furniture to everywhere. Most importantly, obesity is not only caused by genetic determinism but worked out according to social surrounding. After discussing the history of fast-food industry, American lifestyle and dietary habit, we are going to realize the correlation between obesity and disease and looking over the circumstance of American weights (Their Body Mass Index). The thesis also mentions that who should take responsibility for American obesity. Finally, the thesis is looking forward seeing people in any countries have good health condition and then pursuing win-win situation for consumers and producers.