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

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

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.

Study Overview

• Status: Recruiting
• Conditions: Bariatric Surgery Candidate
• Intervention / Treatment: Other: Very Low Calorie Diet Ready-to-eat (VLCD RTE) meals; Other: Standard Care Group

Detailed Description

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).

• Study Type: Interventional
• Enrollment (Estimated): 140
• Phase: Not Applicable

Contacts and Locations

• Study Contact: Name: Melissa Tay Hui Juan; Phone Number: 67725166; Email: melissa_hj_tay@nuhs.edu.sg

Study Locations

• Singapore
  • Singapore, Singapore
    • Recruiting
    • National University Hospital
    • Contact: Melissa Tay
  • Singapore, Singapore
    • Recruiting
    • Alexandra Hospital
    • Contact: Melissa Tay

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: Adult; Older Adult
• Accepts Healthy Volunteers: Yes

Description

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)

Study Plan

How is the study designed?

Design Details

• Primary Purpose: Treatment
• Allocation: Randomized
• Interventional Model: Parallel Assignment
• Masking: None (Open Label)

Number of Arms

2

Arms and Interventions

Participant Group / Arm	Intervention / Treatment
Experimental: Very Low Calorie Diet Ready-to-eat (VLCD RTE) meals; 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 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.
Active Comparator: Liquid Meal Replacement; 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 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.

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Compliance rate of the RTE meals	The compliance rate is assessed via food logging in the nutritionist buddy keto app	Daily for intervention period of 28 days
Blood Ketones Measurement	Fasting blood ketone measurements measured at study visit	1st week, 2nd week, 3rd week, 4th week, surgery day

Secondary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Satisfaction of the RTE meals	Assessed via a self-reported questionnaire with a numeric scale of 1 to 5	3rd week and surgery day
Weight Change	Weight changes at study visit	1st week, 2nd week, 3rd week, 4th week, surgery day

Collaborators and Investigators

• Sponsor: National University Hospital, Singapore
• Collaborators: Alexandra Hospital
• Investigators: Principal Investigator: Melissa Tay, National University Hospital, Singapore

Study record dates

Study Major Dates

• Study Start (Actual): July 1, 2024
• Primary Completion (Estimated): September 1, 2026
• Study Completion (Estimated): September 1, 2026

Study Registration Dates

• First Submitted: June 5, 2024
• First Submitted That Met QC Criteria: June 11, 2024
• First Posted (Actual): June 14, 2024

Study Record Updates

• Last Update Posted (Estimated): September 12, 2025
• Last Update Submitted That Met QC Criteria: September 5, 2025
• Last Verified: September 1, 2025

More Information

Terms related to this study

• Keywords: Weight loss; Body Weight; Very Low Calorie Diet
• Additional Relevant MeSH Terms: Body Weight Changes; Pathological Conditions, Signs and Symptoms; Signs and Symptoms; Weight Loss; Body Weight; Food; Diet, Food, and Nutrition; Physiological Phenomena; Food and Beverages; Meals
• Other Study ID Numbers: 2024/00240

Plan for Individual participant data (IPD)

• Plan to Share Individual Participant Data (IPD)?: NO
• IPD Plan Description: Individual participant data will remain confidential and only accessible via lock and keys by the researchers.

Drug and device information, study documents

• Studies a U.S. FDA-regulated drug product: No
• Studies a U.S. FDA-regulated device product: No
• product manufactured in and exported from the U.S.: No