The goal of this clinical trial is to measure the mean difference of phase angle after nutritional intervention in breast cancer patients. The main question it aims to answer is:

1. Can perioperative nutrition interventions improve phase angle in relation to other bioimpedance parameters, handgrip strength and surgical outcomes in breast cancer population?

Researchers will compare oral nutritional supplement to a placebo to see if oral nutritional supplement can improve phase angle.

Participants will:

1. Be randomized into either arm
2. Take oral nutritional supplement or placebo according to the result of randomization for 7 days preoperatively and 30 days postoperatively
3. Have their measurements (weight, height, phase angle, handgrip strength) done at least 7 days preoperative, 1 day preoperative and 30 days postoperative

Inclusion Criteria:

• Female
• Histopathologically confirmed operable breast cancer
• Aged 18 of years and above
• Consented and scheduled for mastectomy

Exclusion Criteria:

• On enteral supplementation prior to the study
• Lactose intolerance
• Pregnant or lactating
• Previous history of gastrectomy or small bowel resection surgery
• Advanced breast cancer staging, presence of pacemaker, decompensated liver disease, end stage renal failure, uncontrolled diabetes, on steroid therapy or complementary traditional medications

Female