Chronic diseases such as obesity, type 2 diabetes, and cardiovascular disease have become a global health issue in the last century. To prevent and reduce the risk of chronic diseases, healthy eating patterns are believed to be essential. In the dietary guideline, limiting the consumption of saturated fats and trans fats has been proposed due to their associations with multiple health concerns. In this article, the updated information referring to the safety and toxicity of saturated fats, trans fats, and fat-related food contaminants is reviewed. This article includes the corresponding formation pathways, safety issues as well as regulations. Better understanding and improved awareness by the consumer as well as the food industry regarding the safety of fat consumption will help to promote the healthy eating pattern among customers, and therefore improve the public health.