An interventional study of Very Low Calorie Diet Ready-to-eat (VLCD RTE) meals and Standard Care Group in Bariatric Surgery Candidate, sponsored by National University Hospital, Singapore. Recruiting at 2 sites in Singapore. Open to participants aged 21 Years to 65 Years, including healthy volunteers. Per ClinicalTrials.gov, last updated 2025-09-12.
Sponsored by National University Hospital, Singapore · Not applicable, Interventional, and Treatment
Currently, a ketosis-inducing programme, usually a liquid meal replacement, is the standard of care for pre-operative dietary management. However, compliance with liduiqd meal replacement is challenging primarily due to individual taste preferences, limited variety, having to take a liquid diet, lifestyle factors, and other obstacles. Therefore, there is a need for RTE meals to enhance patient satisfaction and compliance, ultimately resulting in improved pre-operative weight loss outcomes. Hence, this RCT study aims to determine whether Very Low Calorie Diet Ready-to-eat (VLCD RTE) meals would lead to greater compliance as measured by blood ketones and meal logging via Nutritionist Buddy app (nBuddy App) compared to standard care liquid meal replacement (Optifast) prior to bariatric surgery.
The obesity rate in Singapore is rising, mirroring a similar worrying global trend. Bariatric surgery has been the only long-term method proven to overcome severe obesity and it has become an increasingly common and effective treatment option. Preoperative weight loss is required to reduce cardiovascular risk, liver volume and decrease intra-abdominal fat. This leads to enhanced surgical visibility and surgical access resulting in reduced intra- and postoperative complications.
Currently, a ketosis-inducing programme, usually a liquid meal replacement, is the standard of care for pre-operative dietary management. However, compliance with liquid meal replacement is challenging primarily due to individual taste preferences, limited variety, having to take a liquid diet, lifestyle factors, and other obstacles. It was found for taste and gastrointestinal side effects to be the main issues.
Therefore, RTE meals are carefully formulated to provide the calculated calorie, controlled net carbohydrate content, and are low in saturated and trans fat. By incorporating these meals as a VLCD diet regime, it would allow patients to still enjoy the chewing sensation and local favourites and flavours, while enjoying mealtime with their friends and families.
In this randomised controlled trial, patients listed for bariatric surgery from the NUH Weight Management Clinic in Singapore will undergo randomization into either the Standard Care or Intervention group during the baseline visit.
All eligible participants (n=140) will be advised to keep within the 800 calorie limit and 50g net carbohydrate limit per day. They will receive guidance from a dietitian on lifestyle changes and pre-bariatric surgery VLCD diets. Participants in both groups will also be advised to download the nutritionist Buddy Keto app for monitoring of compliance, food intake, steps count, weight progress and in app virtual reminders (automated and by dietitians via the chat function).
1,815 studies on the registry are indexed under Weight Loss; 294 are open to participants now.
This study's planned enrollment of 140 is above the median of 80 across 1,561 interventional studies indexed under Weight Loss.
Browse Weight Loss studies →National University Hospital, Singapore is the lead sponsor of 454 studies on the registry; 99 are open to participants now.
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Exclusion Criteria:
Underlined terms in the criteria open these too. Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Weight in kilograms divided by height in metres squared. Example: 70 kg and 1.75 m gives 70 ÷ (1.75 × 1.75) ≈ 22.9.
What counts as overweight or obesity differs between countries (some use lower cut-offs), so go by the range the study states.
BMI (body mass index)
Weight in kilograms divided by height in metres squared. Example: 70 kg and 1.75 m gives 70 ÷ (1.75 × 1.75) ≈ 22.9.
What counts as overweight or obesity differs between countries (some use lower cut-offs), so go by the range the study states.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Participants (n=70) in the VLCD RTE meals group will be advised to follow a calorie-restricted healthy ketogenic diet , consuming a maximum of 800 calories and 50g net carbohydrate intake daily. Participants will be provided with VLCD RTE meals for lunch and dinner for 4 weeks and advised on a healthy keto breakfast. The participants will be expected to self-monitor their weight, physical activity and diet logs via the nutritionist buddy keto app. There will be in app virtual reminders (automated and by dietitians via the chat function) sent via the nutritionist buddy keto application for the 1 month for participants to log in their weight and meals.
Other: Very Low Calorie Diet Ready-to-eat (VLCD RTE) meals
Participants (n=70) in the liquid meal replacement group will be advised to follow very low-calorie diet, with a maximum of 800 calories and 50g net carbohydrate intake daily. Participants will be provided with a liquid meal replacement for breakfast, lunch, and dinner for 4 weeks. Additionally, patients are to prepare 1 serving of non-starchy vegetables are to be included for lunch and dinner. The participants will be expected to self-monitor their weight, physical activity and diet logs via the nutritionist buddy keto app. There will be in app virtual reminders (automated and by dietitians via the chat function) sent via the nutritionist buddy keto application for the 1 month for participants to log in their weight and meals.
Other: Standard Care Group
Participants will be provided with VLCD RTE meals for lunch and dinner for 4 weeks and advised on a healthy ketogenic breakfast. Participant will be expected to adhere to VLCD regimen containing 800 calories per day or fewer and keep within 50g net carbohydrates a day.
Participants will be provided with liquid meal replacement for breakfast, lunch, and dinner for 4 weeks. Additionally, patients are to prepare 1 serving of non-starchy vegetables are to be included for lunch and dinner. Participant will be expected to adhere to VLCD regimen containing 800 calories per day or fewer and keep within 50g net carbohydrates a day.
Compliance rate of the RTE meals
The compliance rate is assessed via food logging in the nutritionist buddy keto app
Time frame: Daily for intervention period of 28 days
Blood Ketones Measurement
Fasting blood ketone measurements measured at study visit
Time frame: 1st week, 2nd week, 3rd week, 4th week, surgery day
Satisfaction of the RTE meals
Assessed via a self-reported questionnaire with a numeric scale of 1 to 5
Time frame: 3rd week and surgery day
Weight Change
Weight changes at study visit
Time frame: 1st week, 2nd week, 3rd week, 4th week, surgery day
Plan to share: No — Individual participant data will remain confidential and only accessible via lock and keys by the researchers.
No publications or documents are linked to this record.
Started Jul 2024 (actual). Primary completion is estimated for Sep 2026, 26 months after the start.
Of 670 non-industry interventional studies with no phase under Weight Loss, half reached primary completion within 25 months of starting (the median), counting those still running; a quarter within 13 and three quarters within 45. This study's planned 26 months is close to that.
Counting every sponsor, half of 729 studies reached it within 24 months; a quarter within 11 and three quarters within 43.
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