**Core Concept**
Bariatric surgical procedures are a group of weight-loss surgeries designed to help individuals with obesity achieve significant weight loss by altering the digestive system's anatomy. These procedures aim to reduce hunger, increase feelings of fullness, and limit calorie absorption.

**Why the Correct Answer is Right**
Ileal transposition is a type of bariatric surgery that involves re-routing the ileum (the final section of the small intestine) to the stomach. This procedure increases the ileum's exposure to nutrients, leading to increased satiety and reduced hunger. By doing so, ileal transposition aims to promote weight loss by reducing calorie intake. This procedure is often considered a more complex surgery compared to other bariatric procedures.

**Why Each Wrong Option is Incorrect**
**Option A:** Gastric banding involves placing an adjustable band around the upper portion of the stomach to create a small pouch, limiting food intake. While effective, it is a different type of bariatric surgery compared to ileal transposition.
**Option B:** Gastric bypass surgery involves creating a small pouch from the stomach and connecting it directly to the small intestine, bypassing a portion of the stomach and small intestine. This procedure is also distinct from ileal transposition and aims to reduce calorie absorption.
**Option C:** Biliopancreatic diversion involves removing a portion of the stomach and re-routing the small intestine to reduce calorie absorption. Although it is a type of bariatric surgery, it is different from ileal transposition.

**Clinical Pearl / High-Yield Fact**
It is essential to note that bariatric surgery is not merely a quick fix for obesity but requires long-term commitment to a healthy lifestyle, including a balanced diet and regular physical activity. Patients undergoing bariatric surgery should be carefully selected and monitored to minimize complications.

**✓ Correct Answer: D. Ileal Transposition**