This communication offers a theoretical interpretation of the current promotion of fasting in France. We articulated different methodological tools as, an analysis of sixty books promoting fasting and published in France since the beginning of the 20th century, an analysis of sources available on the Internet and in the media, an ethnographic fieldwork within fasting centres in France. A particular social configuration of fasting revolves around the development of its dietetic form since the 1990s and a large diversification of its models since the end of the 2000s. We outlined two major turning points: - an international scientific one since the mid-2000 and first evidence of the therapeutic effects on animals; - an national one since the beginning of the 2010s originating from media after a large dissemination of documentaries and books promoting fasting and its therapeutic effects We consider fasting as a control over both the body and the food practices integrated into new reflexivities in the era of nutritionalisation. Media coverage has reversed the negative image of fasting towards a positive one. Fasting appears now as a response for people willing reflexively control food habits and nutritional balance, health and weight, to balance way and quality of life, or to enhance religious, spiritual or sportive practices. It brings also new hopes for preventing and curing diseases (cancer in particular). Confined to natural medicine followers, the therapeutic and medical purposes of fasting (promoted by hygienists and naturopaths) are not integrated into conventional medicine in France, contrary to Germany or Russia. The success of dietetic fasting could be interpreted as a French adaptative modality in the context of a strong control of medicine legitimacy in France. However, the germinating scientific evidence and media dissemination bring into question new blurring boundaries of legitimation at stake when dietetic fasting is concerned.