**Core Concept**
Massive resection of the small bowel can lead to malabsorption of nutrients, including carbohydrates, proteins, fats, and vitamins. The small intestine is responsible for the majority of nutrient absorption in the gastrointestinal tract.

**Why the Correct Answer is Right**
The correct answer is related to the adaptation and compensatory mechanisms of the gastrointestinal tract. After a massive resection of the small bowel, the remaining intestinal tissue can adapt by increasing the surface area for absorption, a process known as "intestinal hyperplasia." This adaptation helps to maintain some level of nutrient absorption. However, the remaining intestinal tissue may not be able to compensate for the loss of the ileum's ability to absorb bile salts, leading to bile salt malabsorption.

**Why Each Wrong Option is Incorrect**
**Option A:** Steatorrhea (fatty stools) is a common complication of massive small bowel resection, especially if the ileum is resected, as it leads to bile salt malabsorption.
**Option B:** Weight loss is a common symptom of malabsorption, which can occur after massive small bowel resection.
**Option C:** Diarrhea is a common symptom of malabsorption, which can occur after massive small bowel resection due to the loss of absorptive surface area.

**Clinical Pearl / High-Yield Fact**
The "ileal brake" hypothesis proposes that the ileum releases a hormone that inhibits gastric emptying and motility, helping to slow down the transit of food through the gastrointestinal tract. After a massive resection of the small bowel, this ileal brake is lost, leading to rapid transit and malabsorption.

**Correct Answer:** D.