Food for Special Medical Purpose in Patients With Digestive Tract Tumor

Inclusion Criteria: * Participant is male or female, between 18 and 75 years old, female participant is non-pregnant or non- lactating, at least 6 weeks postpartum * Participants with digestive tract tumors diagnosed by histological method or radiological diagnosis and scheduled to undergo surgical resection * Participant with NRS-2002 score ≥3 * Participant is willing to comply with the study protocol, able and willing to consume study product according to the protocol * Participants with Body Mass Index 18.5 - 30 kg/m2 * Participant has voluntarily signed and dated an informed consent form (ICF), approved by an Institutional Review Board (IRB) / Independent Ethics Committee (IEC) prior to any participation in the study Exclusion Criteria: * Participant has an expected life expectancy \< 3 months * Participant has contraindications to enteral nutrition (such as active gastrointestinal hemorrhage, bowel obstruction, decompensated short bowel syndrome, high flow intestinal fistula, severe intraperitoneal infection, severe gastrointestinal emptying disorder, unstable vital signs, dyscoagulation, severe nausea, vomiting and/or uncontrolled diarrhea/steatorrhoea) that in the opinion of the study physician cannot be corrected * Participant used parenteral nutrition or had plasma infused, RBC infused, albumin infused, amino acid infused or undergone radiotherapy and/or chemotherapy within 1 week before screening * Participant with serum Albumin \<2.5g/dl at the time of the screening * Participant has moderate to severe anemia, i.e. Hgb \< 90g / L * Patients who plan to receive endoscopic tumor resection or / and palliative surgery * Participant has renal dysfunction (serum creatinine \> 2 times the upper limit of normal (ULN)) * Participant has liver insufficiency \[serum alanine transaminase (ALT) and/or aspartate transaminase (AST) \> 2 times the ULN or severe cholestasis (conjugated bilirubin \> 2 times the ULN)\] * Participant has severe cardiac insufficiency (e.g., Severe arrhythmia or atrial fibrillation; myocardial ischemia or stent surgery with unstable cardiac function within 3 months prior to screening visit ) * Participant states that he/she has had a significant cardiovascular and cerebrovascular event (e.g., myocardial infarction, stroke) within six months prior to screening visit; or stated history of congestive heart failure * Participant with type I diabetes, or type II diabetes with fasting blood glucose ≥8mmol/L * Participant has history of significant neurological or psychiatric disorder * Participant has history of alcoholism, drug abuse or other conditions that may interfere with study product consumption or compliance with study protocol procedures * Participant has a known history of allergy or intolerance to any ingredient in the investigational products * Participant is currently undergoing tumor immunotherapy taking medications/substances that could profoundly modulate appetite, metabolism or inflammatory level 1. Appetite enhancers, pregnancy promoters, steroids (nasal inhalation, topical and optical steroids are acceptable); 2. Anti-inflammatory fat emulsions or other oral nutritional supplementations/drugs containing Omega-3 fatty acids, protein, glutamine, or arginine. 3. Dexamethasone, growth hormone or other drugs affecting metabolism; * Participant is currently undergoing tumor immunotherapy or taking medications/substances that could profoundly modulate immune function, such as PD1 or PDL1 inhibitors; CTLA-4 inhibitor; Thymosin; Azathioprine; Cyclosporine; Tacrolimus; Tumor necrosis factor antagonist; Lentinan; immune-modulating Chinese medicine * Participant with active tuberculosis and HIV infection * Participant participated in any clinical trial within four weeks prior to the screening visit.