Preventing Muscle Loss After Bariatric Surgery: Protein-Collagen Supplementation and Resistance Exercise

Preventing Muscle Loss in the Early Postoperative Period of Bariatric Surgery With a Combination of Whey Protein, Hydrolyzed Collagen, and Resistance Exercise: A Prospective, Randomized, Controlled Clinical Study

The aim of this clinical trial is to investigate the effectiveness of collagen, considered a new approach to prevent muscle mass loss after bariatric surgery, and to demonstrate the relationship between this effect and exercise. The key questions it aims to answer are:

Does whey protein supplementation with collagen combined with resistance exercise prevent muscle mass loss after bariatric surgery? Do whey protein supplementation with collagen combined with resistance exercise affect fat mass after bariatric surgery?

Researchers will compare collagen with whey protein.

The study groups and interventions to be implemented are summarized below:

Group 1: Control Group (CG; n: 10) Whey protein supplementation will be administered Vitamin and mineral supplementation will be administered No resistance exercise will be performed The participants will eat according to bariatric surgery nutrition guidelines and perform physical activities.

Group 2: Whey Protein + Collagen + Exercise Group (WPCEG; n: 10) Whey protein supplements with collagen will be given. Vitamin and mineral supplements will be given. Resistance exercise will be performed. They will eat according to bariatric surgery nutrition guidelines and perform physical activities.

They will begin a resistance exercise program 4 weeks after surgery.

Group 3: Whey Protein + Collagen + No Exercise Group (WPCG; n: 10) Whey protein supplements with collagen will be given. Vitamin and mineral supplements will be given. No resistance exercise will be performed. They will eat according to bariatric surgery nutrition guidelines and perform physical activities.

Group 4: Whey Protein + Exercise Group (WPEG; n: 10) Whey protein supplements will be given. Vitamin and mineral supplements will be given. Resistance exercise will be performed. They will eat according to bariatric surgery nutrition guidelines and perform physical activities.

A resistance exercise program will begin at 4 weeks post-operatively.

Study Overview

• Status: Recruiting
• Conditions: Muscle Loss; Bariatric Surgery
• Intervention / Treatment: Dietary supplement: Whey protein supplement; Dietary supplement: Vitamin and Mineral Supplementation; Dietary supplement: Hydrolyzed Collagen Supplement; Behavioral: Resistance Exercise Program

Detailed Description

Bariatric surgery is an effective method for treating obesity, but a significant decrease in skeletal muscle mass can be observed in the early postoperative period. This loss of muscle mass can negatively affect physical functions, reduce metabolic rate, and make long-term weight maintenance more difficult. Therefore, developing strategies to prevent muscle loss after bariatric surgery is of great clinical importance.

The use of whey protein to support muscle protein synthesis in the postoperative period is a common practice. In recent years, there has been increased scientific interest in the potential of collagen peptides, especially when used in conjunction with resistance exercise, to contribute to muscle mass preservation. However, studies evaluating the combined effect of collagen supplementation and exercise programs in addition to whey protein in individuals undergoing bariatric surgery are limited.

This clinical study aims to investigate the effectiveness of adding collagen to standard whey protein supplementation and a resistance exercise program in preventing muscle loss. Four different groups will be designed to evaluate the independent and combined effects of collagen and exercise:

1. Group receiving only whey protein,
2. Whey + collagen + exercise group,
3. Whey + collagen but no exercise group,
4. Whey + exercise but no collagen group.

All participants will follow a standard post-bariatric surgery nutrition protocol and receive routine vitamin and mineral supplements. The resistance exercise program will begin four weeks after surgery; it will consist of progressively more intense, supervised exercises targeting large muscle groups. Body composition assessments will be performed at baseline and at specified follow-up weeks. The primary outcome measure is change in skeletal muscle mass; secondary outcome measures are fat mass, functional capacity, and exercise compliance.

This study is expected to contribute to the identification of optimal nutrition and exercise strategies to reduce muscle loss after bariatric surgery.

• Study Type: Interventional
• Enrollment (Estimated): 35
• Phase: Not Applicable

Contacts and Locations

• Study Contact: Name: Rüken A Samancı, Msc; Phone Number: +90 543 939 15 94; Email: rasamanci@medipol.edu.tr

Study Locations

• Turkey (Türkiye)
  • Fatih
    • Istanbul, Fatih, Turkey (Türkiye)
      • Recruiting
      • İstanbul Medipol University
      • Contact: Rüken A Samancı, Msc; Phone Number: +90 543 939 15 94; Email: rasamanci@medipol.edu.tr

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: Adult
• Accepts Healthy Volunteers: No

Description

Inclusion Criteria:

• Being between 20-50 years old
• Body mass index; 35 ≤ BMI< 60 kg/m2
• Not being pregnant
• Not being addicted to alcohol and drugs
• Not having entered menopause
• No exercise restrictions

Exclusion Criteria:

• Having at least one of the following inflammatory bowel diseases, upper gastrointestinal bleeding, advanced psychiatric diseases, cancer, and kidney failure.
• using statins
• be pregnant
• Being addicted to alcohol and drugs
• to have entered menopause
• Having exercise restrictions
• Becoming a professional athlete
• Having done more than 60 minutes of regular and structured exercise per week in the last year

Study Plan

How is the study designed?

Design Details

• Primary Purpose: Treatment
• Allocation: Randomized
• Interventional Model: Parallel Assignment
• Masking: Triple

Number of Arms

4

Arms and Interventions

Participant Group / Arm	Intervention / Treatment
Active Comparator: Control Group (CG); Whey protein supplementation will be provided. Vitamin and mineral supplementation will be administered. No resistance exercise will be performed. Participants will follow bariatric surgery nutrition guidelines and maintain their regular physical activities. A comparison will be made with the other groups as the control group.	Dietary supplement: Whey protein supplement; Oral whey protein supplement provided daily according to bariatric surgery nutrition protocol.; Dietary supplement: Vitamin and Mineral Supplementation; Routine vitamin and mineral supplementation according to bariatric surgery follow-up protocol.
Experimental: Whey Protein + Collagen + Exercise Group (WPCEG); Collagen-containing whey protein supplementation will be provided. Vitamin and mineral supplementation will be given. Resistance exercises will be performed. Participants will follow bariatric surgery nutrition guidelines and maintain their physical activities. They will begin the resistance exercise program in the 4th week after surgery.	Dietary supplement: Whey protein supplement; Oral whey protein supplement provided daily according to bariatric surgery nutrition protocol.; Dietary supplement: Vitamin and Mineral Supplementation; Routine vitamin and mineral supplementation according to bariatric surgery follow-up protocol.; Dietary supplement: Hydrolyzed Collagen Supplement; Oral hydrolyzed collagen supplement provided daily in combination with whey protein.; Behavioral: Resistance Exercise Program; Structured resistance exercise program initiated at postoperative week 4, supervised, 3 times per week.
Experimental: Whey Protein + Collagen + Non-Exercise Group (WPCG); Collagen-containing whey protein supplementation will be provided. Vitamin and mineral supplementation will be administered. No resistance exercises will be performed. Participants will follow bariatric surgery nutrition guidelines and maintain their physical activities.	Dietary supplement: Whey protein supplement; Oral whey protein supplement provided daily according to bariatric surgery nutrition protocol.; Dietary supplement: Vitamin and Mineral Supplementation; Routine vitamin and mineral supplementation according to bariatric surgery follow-up protocol.
Experimental: Whey Protein + Exercise Group (WPEG); Whey protein supplementation will be provided. Vitamin and mineral supplementation will be given. Resistance exercises will be performed. Participants will follow bariatric surgery nutrition guidelines and maintain their physical activities. They will begin the resistance exercise program in the 4th week after surgery.	Dietary supplement: Whey protein supplement; Oral whey protein supplement provided daily according to bariatric surgery nutrition protocol.; Dietary supplement: Vitamin and Mineral Supplementation; Routine vitamin and mineral supplementation according to bariatric surgery follow-up protocol.; Behavioral: Resistance Exercise Program; Structured resistance exercise program initiated at postoperative week 4, supervised, 3 times per week.

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Change in Skeletal Muscle Mass (kg) Measured by BIA	Skeletal muscle mass (kg) will be measured using a multi-frequency bioelectrical impedance analysis (BIA) device. The outcome will be reported as the mean change from baseline at each time point in each study group.	Baseline (preoperative), postoperative week 4 (day 29), and postoperative week 12 (day 85)

Secondary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Change in Fat Mass (kg) Measured by BIA	Fat mass (kg) will be measured using BIA. Results will be summarized as the mean change from baseline for each group.	Baseline, week 4, and week 12

Collaborators and Investigators

• Sponsor: Medipol University
• Investigators: Principal Investigator: Halit E Taşkın, Dr., Cerrahpaşa Faculty of Medicine, General Surgery; Principal Investigator: Nihal Z Erdem, PhD, Istanbul Medipol University, Nutrition and Dietetics; Principal Investigator: Bürke Köksalan, PhD

Study record dates

Study Major Dates

• Study Start (Actual): August 2, 2022
• Primary Completion (Estimated): December 20, 2025
• Study Completion (Estimated): January 30, 2026

Study Registration Dates

• First Submitted: November 17, 2025
• First Submitted That Met QC Criteria: December 10, 2025
• First Posted (Actual): December 26, 2025

Study Record Updates

• Last Update Posted (Actual): December 26, 2025
• Last Update Submitted That Met QC Criteria: December 10, 2025
• Last Verified: December 1, 2025

More Information

Terms related to this study

• Keywords: Bariatric Surgery; Whey protein; Resistance exercise; Collagen; Muscle loss
• Additional Relevant MeSH Terms: Neurologic Manifestations; Nervous System Diseases; Neuromuscular Manifestations; Pathological Conditions, Anatomical; Atrophy; Pathological Conditions, Signs and Symptoms; Signs and Symptoms; Muscular Atrophy; Physiological Effects of Drugs; Micronutrients; Pharmacologic Actions; Chemical Actions and Uses; Food; Diet, Food, and Nutrition; Physiological Phenomena; Food and Beverages; Nutrients; Vitamins
• Other Study ID Numbers: E-66291034-772.02-3053

Plan for Individual participant data (IPD)

• Plan to Share Individual Participant Data (IPD)?: NO
• IPD Plan Description: Individual participant data will not be shared because this study involves identifiable clinical and nutritional data collected at a single center, and participant privacy cannot be fully ensured despite anonymization

Drug and device information, study documents

• Studies a U.S. FDA-regulated drug product: No
• Studies a U.S. FDA-regulated device product: No