There exist few studies in the student sector about the effects of fast food that causes obesity. The percentage of overweight students has increased in Mexico in the recent years. Also, it has been noted an increment in the cases of diabetes and cardiovascular illness. This paper shows the relation between a deficient alimentation and the increment of obesity and depression in students at university level. A disproportionate level of serotonin can cause depression. It is noted that the depressive effect is a constant that appears due to a deficient alimentation and this affects negatively the academic performance of the students. It has been made a tracking to the students in one university in Monterrey city in order to know which are the preferred foods of the students and evaluate the effects of their alimentation. It is observed that there exist many factors that affect the alimentation of the students, for example a lack of good food, budget, among others. Some proposals are given to improve the health of students. It also has been obtained information from surveys to study the impact of the food price, service time, the environment of the place and the quality of the food.