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NCT Number: NCT06461247

Compliance With Standard Care vs Ready to Eat Meals Prior to Bariatric Surgery

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.

Recruiting

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Key information

Age range

21 year–65 year

Sex eligibility

All sexes

Study type

Interventional

Phase

Not applicable

Primary location

Alexandra Hospital, Singapore

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About this study

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.

  • Standard Care Group (n=70): Participants will be provided with liquid meal replacements 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.
  • Intervention Group (n=70): Participants will be provided with the VLCD RTE meals for lunch and dinner for 4 weeks and advised on a healthy keto breakfast.

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).

Who can participate

Healthy volunteers accepted: Yes

Only the study team can determine whether someone qualifies for participation.

Inclusion criteria

  • Adults aged 21 to 65 years old
  • Scheduled for bariatric surgery at least 1 month prior
  • BMI ≥ 27.5 kg/m2 (with type 2 diabetes mellitus or metabolic syndrome)
  • Owns a smart phone with data plan
  • English speaking

Exclusion criteria

  • Cognitive impairment.
  • Hypothyroidism
  • Chronic kidney disease
  • Hypothyroidism
  • Depression with ongoing psychology follow up
  • Type 1 diabetes
  • Liver Cirrhosis
  • Pregnancy
  • Heart Failure
  • Active cancer or in remission for less than 5 years
  • Vegetarian
  • Observing the fast during the month of Ramadan
  • Undergoing treatment with anti obesity medications (eg: Phentermine/Orlistat/Contrave/GLP-1 analogues etc)

Treatment and study plan

Very Low Calorie Diet Ready-to-eat (VLCD RTE) meals

Other

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.

Standard Care Group

Other

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.

Primary outcomes

  1. Compliance rate of the RTE meals

    Time frame: Daily for intervention period of 28 days

    The compliance rate is assessed via food logging in the nutritionist buddy keto app

  2. Blood Ketones Measurement

    Time frame: 1st week, 2nd week, 3rd week, 4th week, surgery day

    Fasting blood ketone measurements measured at study visit

Secondary outcomes

  1. Satisfaction of the RTE meals

    Time frame: 3rd week and surgery day

    Assessed via a self-reported questionnaire with a numeric scale of 1 to 5

  2. Weight Change

    Time frame: 1st week, 2nd week, 3rd week, 4th week, surgery day

    Weight changes at study visit

Study contacts

Contact information is provided by the study sponsor or research team.

Melissa Tay Hui Juan

CONTACT

[email protected]

67725166

Sponsors and collaborators

Lead sponsor

National University Hospital, Singapore

Other

Collaborators

  • Alexandra Hospital

Registry information

Official study title

Compliance With Standard Care vs Ready to Eat Meals Prior to Bariatric Surgery - a Randomised Controlled Trial

Important dates

Study start
2024
Primary completion
2026
Study completion
2026
First posted
Jun 14, 2024
Registry last updated
Sep 12, 2025

OpenTrials presents study information sourced from ClinicalTrials.gov. The official registry record should be consulted for the latest information.

View the official ClinicalTrials.gov record (opens in a new tab)

This listing is for discovery and informational purposes only. It is not medical advice, does not guarantee that a study is recruiting, and does not determine eligibility. Contact the study team and a qualified healthcare professional when considering participation.

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