This paper shows different techniques use in operation research to encounter with various diet problems. Each diet problem has its respective cost restriction and objective functions. The planning adequate menus involves consideration of several types of constraints such as the desired nutritional content, the amount of food to be consumed and others. The mathematical models were built to decide a diet plan as optimal solution which satisfy all the requirements and restrictions. The application of different optimization approaches and drawback in each technique has been discussed. The paper also illustrates the use of integer programming and improvement that can be done. An optimal and practical solution is obtained to solve the diet problem of eczema patients.