Here is the design of a clinical trial:

Official Title: Intensive Perioperative Nutrition Therapy

Included conditions:
- Perioperative Complication

Study Armgroups:
- {'label': 'Supplements Group - SS', 'type': 'EXPERIMENTAL', 'description': 'The SS will be received tailored and more intensive and ongoing nutrition support and lifestyle advice as compared with the NN and will be supplemented with ONS, available in 400g/can, providing 226 kcal/serving and 9.6 g protein/serving. Participants will be encouraged to consume the ONS in small, frequent, in between meals.\n\nAll participants will receive standard post-operative care from clinical and nurse staff with commencement of free fluids and reintroduction of normal diet without interference by the researcher or protocol. The postoperative course will be carefully monitored. While complications will be noted as major or minor by using validated criteria (Buzby et al., 1988).', 'interventionNames': ['Dietary Supplement: Oral Nutrition Support']}
- {'label': 'Control Group - NN', 'type': 'NO_INTERVENTION', 'description': 'While participants in NN which referred as control group will received the standard care of the clinic without supplemented with ONS. Nutritional advice will be based on a guideline specifically focused on treatment of symptoms such as nausea, vomiting, loss of appetite and diarrhoea, and how to deal with the symptoms through nutritional approaches. Basically, the advice will be given by the oncologist or nurses in the clinic.\n\nAll participants will receive standard post-operative care from clinical and nurse staff with commencement of free fluids and reintroduction of normal diet without interference by the researcher or protocol. The postoperative course will be carefully monitored. While complications will be noted as major or minor by using validated criteria (Buzby et al., 1988).'}

Interventions:
- {'type': 'DIETARY_SUPPLEMENT', 'name': 'Oral Nutrition Support', 'description': 'Intensive Nutrition Intervention', 'armGroupLabels': ['Supplements Group - SS']}

Primary Outcomes:
- {'measure': 'Length of Bowel function', 'description': 'To compare the effect of intensive perioperative nutrition therapy versus usual care on the length of bowel function. The duration of bowel start function post-operatively in hours or days will be recorded. The duration covers from zero hours after surgery until the first day of bowel function presented. The start of bowel function is the first day of commencement of any type of fluids or solid food given', 'timeFrame': '2 months'}
- {'measure': 'Length of solid food toleration', 'description': 'To compare the effect of intensive perioperative nutrition therapy versus usual care on the length of solid food toleration. The duration of solid food toleration post-operatively in hours or days will be recorded. The duration covers from zero hours after surgery until the first day of reintroduction of solid food.', 'timeFrame': '2 months'}
- {'measure': 'Length of hospital stay', 'description': 'To compare the effect of intensive perioperative nutrition therapy versus usual care on the length of hospital stay. The duration of hospital stay in days will be recorded. The duration covers from the day of ward admission (before operation) until discharge (after operation).', 'timeFrame': '2 months'}

Please estimate the sample size based on the assumption: 
A power (β) of 90%, a significance level (α) of 0.05, and a dropout rate of 20% were assumed.
Sample size calculation
          A systemic review study in 2016 showed that early feeding has a significantly shorter length of hospital stay (p<0.01) compared to the late timing of feeding with a difference of â1.72 days and not associated with an increase in clinically relevant complications [26]. Several other studies also support early nutrition for surgery patients significantly shortening the length of hospital stay [27â29].
          LOS was chosen to calculate the sample size because it has been used widely as a primary outcome in most nutrition-related RCT studies [30â32] among patients undergoing surgery. The sample size was calculated based on the data from a study conducted on colorectal cancer patients undergoing surgery [30]. The primary outcome was calculated based on the difference in LOS between two groups (control and intervention group) which was 3.45 days.
          A large effect size of 0.8 for clinical significance was assumed, and practicality for this research was considered, with a power (Î²) of 90% and a probability (Î±) of 0.05. Allowing for a âdrop-outâ rate of 20% for the RCT study, we aim to recruit participants who will be included in each group, with the final sample size calculated as 68 participants with 34 participants in each group, respectively.