To Test the Food for Special Medical Purpose in Perioperative Patients With Gastrointestinal Cancer

Inclusion criteria 1. Agreed to participate in the study with signed ICF; 2. Age 18-75 years; 3. Patient has gastrointestinal cancer confirmed by histological or imagological method and scheduled for resection via open or laparoscopic surgery; 4. Radiotherapy and/or Chemotherapy was not performed within 2 weeks before screening; 5. Hemoglobin ≥ 90 g/L 6. Albumin ≥ 2.5 g/dL 7. BMI ≥18.5 and ≤29 kg/m2; 8. ECOG Performance status 0-2 preoperatively; 9. Expected survival time \>6 months. Exclusion criteria 1. Contraindication or intolerance against EN, e.g., acute gastrointestinal bleeding, ileus (Grade≥3 NCI-CTCAE v 5.0); 2. Any congenital defect of amino acid or carbohydrate metabolism, such as phenylalaninemia, galactosaemia; 3. Conditions requiring emergency surgery; 4. Conditions other than cancer and surgery that can be associated with loss of body weight e.g. serious active clinical infections (\> Grade 2, NCI-CTCAE 5.0), including active tuberculosis, or self-reported HIV infection or active hepatitis B or C; 5. Known treatment refractory metabolic disease (e.g., poorly-controlled diabetes mellitus or fasting blood glucose≥ 10mmol/L, hyperthyroidism, hypothyroidism, metabolic acidosis); 6. Cardiac dysfunction (New York Heart Association Functional Class \> III); 7. Severe hepatic dysfunction associated with significant increase of AST or ALT \> 5 ULN or bilirubin \> 3 ULN; 8. Severe renal dysfunction associated with serum creatinine concentration \> 1.5 ULN and/or required dialysis; 9. Active treatment refractory bleeding; 10. Other malignancies in the last 3 years (except for successfully treated in situ basocellular skin or in situ cervical uterine tumours); 11. Known disease that could seriously affect the digestion and absorption of the IMPs; 12. History of drug or alcohol abuse within 6 months prior to screening; 13. Current use of medication or nutritional supplements containing more than 500 mg of EPA+DHA/day or fish oil capsules/ supplements containing more than 500 mg EPA + DHA/day at screening; 14. Current use of muscle growth supporting substances (e.g., anabolics) at screening; 15. Planned chemotherapy, radiotherapy or immunotherapy during the first 12 days following the surgical tumor resection; 16. Transfusion of blood products within 1 week before screening; 17. Known allergy to contents of the study product or control product; 18. Pregnancy or lactation; 19. Participation in another clinical study with an investigational drug, FSMP or an investigational medical device one month prior to start of study or planned participation in another clinical trial as specified before during the course of the study period; 20. Patient who is unable to understand the spoken and written information or not willing or not able to comply with scheduled visits and the requirements of the study protocol; 21. Considered not suitable for study participation by the investigator