Nutrition in the Preoperative Period: Due to the complexity of obesity, the presence of many criteria, and the importance of lifestyle changes after surgery, patients need to be evaluated, monitored, and educated by a multidisciplinary team. Preoperative evaluation of patients should be done by bariatric specialist doctors, psychiatrists and dietitians. During the evaluation, patients are asked to create a food consumption record regarding their nutritional history, alcohol use, food preferences and daily energy intake. During a detailed nutritional evaluation, the dietitian makes adjustments to the patients' nutritional habits beforehand and helps prevent nutrition-related complications after the surgery.

Achieving some weight loss before surgery helps minimize these complications. Nutrition in the Postoperative Period It is necessary to support the patient's intake of adequate nutrients to accelerate tissue healing after the operation. It is necessary to minimize reflux, early feeling of fullness and dumping syndrome that may occur after surgery. There should be a gradual transition in their diet. The gradual diet sequence of bariatric surgery patients should be clear liquid diet, liquid diet, puree diet, soft diet and standard diet. Clear liquid diet The first stage of postoperative nutrition is the clear liquid diet. The body must be supplied with fluid, electrolytes and a limited amount of energy. It is recommended to use clear liquid diet for 1-2 days. By gradually increasing the stomach volume, approximately 2 liters (8-10 glasses) of liquid should be consumed, half of which should be water. It should be consumed sip by sip. The use of straws should be avoided as there is a high possibility of swallowing air, which disturbs the stomach. Liquid diet This diet is applied for 2 weeks after post-operative checks. The liquid diet has more fiber than the clear liquid diet. 60-80 grams of protein should be provided per day. 2000 ml fluid support should be provided.

Recommended fluids; water, lean meat/chicken broth, unsweetened fruit juices, decaffeinated coffee, light tea, lactose-free milk, buttermilk, kefir, sugar-free compote water, pudding made from unsweetened skim milk, lactose-free yoghurt. Puree period. Puree diet lasts approximately 2 weeks. All stages of the liquid diet are also valid in this period. In addition to oms; low-fat cottage cheese, eggs (for the first 1-2 days, only the white of the egg can be included in the breakfast in a boiled form.) mashed potatoes, fruit purees, well-cooked vegetable purees that do not cause gas (such as pumpkin, spinach, green beans). If protein support is not sufficient during the puree period, consult a doctor. Protein support can be provided under the supervision of a dietitian. Soft diet This diet is a transition diet. It includes grinding, crushing and pureeing processes. Soft diets are applied in the 5th, 6th, 7th, and 8th weeks after surgery. The target is 60-80 grams of protein per day.

As protein-based foods increase, protein support is reduced. Liquids should be avoided during meals and one should wait 30 minutes after eating to consume liquids. Spicy, very hot or very cold foods should be avoided. Standard diet: This diet is started after the 9th week after surgery, if everything is going normal. Target protein intake should be 60-80 grams. You can start with the consumption of raw vegetables such as lettuce and carrots. Attention should be paid to the diet of 3 main meals and 3 snacks, and no other meals should be missed. Caffeinated drinks are prohibited for the first 4 months. Stay away from hot and spicy foods.