Questions: Identify which nutrient's digestion is affected by gallbladder disease: fat protein carbohydrate fiber

The answer is the first one: fat.

Explanation for each option:

1. Fat: The gallbladder stores bile produced by the liver, which is essential for the digestion and absorption of fats. Bile emulsifies fats, making them easier to digest. If the gallbladder is diseased, bile release can be impaired, leading to compromised fat digestion.

2. Protein: Protein digestion primarily occurs in the stomach and small intestine, facilitated by enzymes like pepsin and trypsin. The gallbladder does not play a direct role in protein digestion, so gallbladder disease does not significantly affect this process.

3. Carbohydrate: Carbohydrate digestion begins in the mouth with salivary amylase and continues in the small intestine with pancreatic amylase. The gallbladder is not involved in carbohydrate digestion, so its disease does not impact this process.

4. Fiber: Fiber is not digested by human enzymes but is fermented by gut bacteria in the large intestine. The gallbladder does not influence fiber digestion, so its disease does not affect this process.

In summary, gallbladder disease primarily affects the digestion of fats.