Interventions for Weight Regain After Bariatric Surgery

Comparison of Revisional Surgery, Ketogenic Diet, and Intermittent Fasting in Bariatric Surgery Patients With Weight Regain: A Prospective Randomized Controlled Study

Study Objective:

The aim of this study is to evaluate the effects of revisional bariatric surgery (RBS), very low-calorie ketogenic diet (VLCKD), and intermittent fasting (IF) on nutritional habits and clinical outcomes (anthropometric and biochemical measurements) in patients with insufficient weight loss (IWL) or weight regain (WR) after bariatric surgery, and to compare these findings with those of a control group.

Study Hypotheses:

1. In patients with IWL or WR after bariatric surgery, a diet following the bariatric care guidelines (BCGs) after revisional bariatric surgery (RBS) improves nutritional habits, anthropometric, and biochemical parameters.
2. In patients with IWL or WR after bariatric surgery, VLCKD improves nutritional habits, anthropometric, and biochemical parameters.
3. In patients with IWL or WR after bariatric surgery, IF regimen improves nutritional habits, anthropometric, and biochemical parameters.
4. In patients with IWL or WR after bariatric surgery, the diet program recommended by the ASMBS as part of standard post-bariatric care improves nutritional habits, anthropometric measurements, and biochemical parameters.

Inclusion Criteria:

• Patients aged between 18 and 45 years who have undergone bariatric surgery (BS).
• Experiencing inadequate weight loss (IWL) within 18 months after surgery or weight regain (WR) following successful weight loss.
• Definitions used in the study:

IWL is defined as <50% excess weight loss (EWL) 18 months postoperatively. WR is defined as >25% regain of the lost weight (from the lowest achieved weight).

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Exclusion Criteria:

• Pregnant or lactating women.
• Patients with acute illnesses, infections, or comorbidities that may affect treatment efficacy or safety (e.g., cancer, type 1 diabetes, renal or hepatic failure, recent stroke or myocardial infarction, nephrolithiasis, substance or alcohol abuse, eating disorders, severe depression or other psychiatric disorders, inflammatory bowel disease, neoplasms, arrhythmic heart diseases, heart failure, respiratory failure).
• Patients currently receiving corticosteroid therapy.
• Professional athletes.