In a society that functions at a high speed, fast food has quickly been adopted as the preferred food of choice. Fast food industries are successful because they offer consumers a quick, convenient and tasty meal. Most of the fast foods are rich in fats and poor in other nutrients. Common fast food includes burgers, pizzas, and chicken products as well as desserts. The main purpose of this paper is to examine the relationship between eating fast food and its impact on human health in fast food restaurants in Cairo city in Egypt. The research was conducted using a survey method. Questionnaire forms were distributed to restaurant guests in addition to pre-planned interviews with restaurant managers according to the selected sample, and descriptive statistics was adopted. Data were analyzed by using SPSS software version 24. The research results show that fast foods are an integral part of life, and coming with it is a massive increase in obesity and associated problems.