# Nutritional Support for Liver Diseases
## 2 Nutritional Support for Liver Diseases
### Liver Transplantation
#### 2.4.2 Nutritional Support after Liver Transplantation  
Patients undergoing liver transplantation have similar caloric needs to those after abdominal surgeries [5]. Feeding should be started as soon as possible after the operation is completed. This approach reduces the risk of postoperative symptoms such as nausea, hunger, thirst, and malaise [154].  
Early Period (12-24 h)  
According to the ERAS protocol, normal oral food intake and/or enteral nutrition (nasogastric tube/jejunostomy) should be started within 12-24 h after the surgery (depending on patient tolerance). Additional nutritional support should be provided to malnourished patients and patients undergoing prolonged postoperative fasting lasting more than 5 days, e.g., in the event of complications [147; 155]. The inclusion of parenteral nutrition is considered in a situation where it is not possible to use the oral route (jejunostomy/enteral tube).  
Due to the lack of clear evidence, there is no obligation to use dietary supplements in patients after liver transplantation [147]. It should be noted that a high percentage of patients use herbal preparations and dietary supplements; therefore, they should be educated about possible toxicity and drug interactions [163].  
Later Period  
People who have undergone a liver transplant have a higher risk of developing diabetes due to the immunosuppressive drugs used. If diagnosed, the patient should modify their diet by, e.g., limiting the consumption of simple sugars. The hyperglycemic effect of tacrolimus can be reduced by reducing the dose [150].  
Immuno-suppressive drugs can also lead to increased potassium levels. If such a situation occurs, it is recommended that the patient limit the products of its source in the diet. This situation usually occurs in the early perioperative period [156]. Among the patients, a reduced level of magnesium can also be observed. In order to increase its level, it is recommended to use a balanced diet rich in, for example, whole grains, goats, legumes, or nuts. Taking magnesium supplements can lead to diarrhea [150].  
Liver transplantation is the main definitive treatment for end-stage liver disease and eliminates several factors contributing to the pathogenesis of sarcopenia. Hepatocyte function is restored, ascites regresses, and portal pressure is lowered. On the other hand, the patient must take immunosuppressive drugs that adversely affect muscle mass by activating myokines, as well as increasing fat mass (sarcopenia obesity). Studies have shown that muscle mass can stabilize, increase, or decrease after a liver transplant. So, there are no clear results on this. Post-transplant obesity, in addition to the effect of drugs, may also be partly related to excessive caloric intake. Thus, the patient's adherence to a nutritional plan with an adequate supply of protein and calories may reduce the risk of developing obesity, insulin resistance, and sarcopenia obesity [7].  
The largest increase in body weight usually occurs in the first 6 months after the operation [155]. It should be noted that the increase in body weight is usually continuous, and patients also gain weight in subsequent years, which results in the development of obesity and being overweight [150].