The Subjective Global Assessment (SGA) will be used to assess changes in nutritional status. SGA is an easy-to-apply, low-cost and reliable method that is frequently used in the evaluation of malnutrition status. After the patient is evaluated according to certain criteria, the level of malnutrition is determined by the evaluator's subjective point of view. It is a four-part evaluation. These are weight loss and food intake history, gastrointestinal system symptoms, functional capacity, metabolic requirement, and physical examination. The analysis of the information and the results from it are scored as A, B, C. If the patient is well-nourished, he is classified as A, moderately malnourished, B, and severely malnourished, C. SGA will be applied by the researchers in face-to-face meetings within 7 days before the operation, on the 7th day, 15th day, 1st month and 3rd month after the operation.

To evaluate the food consumption of the patients included in the study, at the preop 7 days, postoperative 7th day, 15th day, 1st month and 3rd month will be taken with 24-hour recall method. The amount of nutrients included in the meals will be calculated by using the "Standard Recipes" book, and the measurement amounts will be calculated by using the "Food Photo Catalogue" book. The data obtained from the 24-hour recall method will be analyzed using the "Computer Assisted Nutrition Program, Nutrition Information Systems Package Program (BEBIS)" and the amount of energy, carbohydrates, protein, fat, fiber and micronutrients consumed by participants will be calculated. Intake of energy, macro nutrients, fiber and micronutrients will be compared with the preop 7 days, postoperative 7th day, 15th day, 1st month and 3rd.

In this study, a questionnaire consisting of open and closed-ended questions will be used to determine the chewing difficulties of individuals. With open-ended questions, foods that are difficult to chew and the methods used to consume these foods will be questioned. In the follow-up interviews, closed-ended questions such as the ability to chew the previously listed foods are "easy to chew", "I have a little difficulty", "I have a lot of difficulty / can't chew at all". If individuals say, "I have a little or a lot of difficulty" while chewing hard foods and "I have some or a lot of difficulty" when chewing soft foods, they will be evaluated as "difficulty in chewing".

The pre-op and post-op physical activity levels of the patients included in the study will be evaluated with the short version of the International Physical Activity Questionnaire (IPAQ), which will be administered at each interview. The International Physical Activity Questionnaire Short Version (7 questions) is used for seven days to assess physical activity in 4 domains, including leisure, indoor, work and transport-related physical activity. Physical activity level is classified as active, mildly active and active according to general scores.