This article reviews Western dietary attitudes and lifestyle choices by identifying the environmental, social and personal factors that determine said attitudes and choices. Environmental factors exert a major influence on, and complicate, dietary behavior, primarily by facilitating the consumption of meals away from home and by minimizing time dedicated to meal preparation and consumption. Social factors, from mass media to advertising and cultural traditions, also influence food intake, to an extent that is still underestimated. Ignorance of the real influence of environment and society on food choices could well blind consumers to the real significance of such choices. Accordingly, this review discusses differing aspects of emerging dietary trends and/or philosophies, and underlines their potentially harmful influence on health. Western countries are increasingly witnessing a dichotomy between the findings of nutritional science and the choices that dietary trends propose and impose. Coinciding with the obesity epidemic and the spread of other food-related diseases, this dichotomy calls for the development of effective preventive strategies.