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

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.

• Whey protein supplement (Dietary supplement): Oral whey protein supplement provided daily according to bariatric surgery nutrition protocol.
• Hydrolyzed Collagen Supplement (Dietary supplement): Oral hydrolyzed collagen supplement provided daily in combination with whey protein.
• Vitamin and Mineral Supplementation (Dietary supplement): Routine vitamin and mineral supplementation according to bariatric surgery follow-up protocol.
• Resistance Exercise Program (Behavioral): Structured resistance exercise program initiated at postoperative week 4, supervised, 3 times per week.

Primary outcomes

• Change in Skeletal Muscle Mass (kg) Measured by BIA [Baseline (preoperative), postoperative week 4 (day 29), and postoperative week 12 (day 85)]: 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.

Secondary outcomes

• Change in Fat Mass (kg) Measured by BIA [Baseline, week 4, and week 12]: Fat mass (kg) will be measured using BIA. Results will be summarized as the mean change from baseline for each group.

Sex: All, ages: 20 Years to 50 Years

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

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