These substances cause excessive amounts of water to remain in the stool, leading to diarrhea. Certain foods (such as some fruits and beans) and sugar substitutes in dietetic foods, candy, and chewing gum (for example, hexitols, sorbitol, and mannitol) can cause osmotic diarrhea.
The four most common types of green lettuce -- green leaf, romaine, butterhead and iceberg -- have 13 to 17 calories in 100 grams, which is about a 1/2-cup serving of shredded lettuce. They deliver 1 gram of protein, or about 2 percent of the recommended daily intake.
Green leaf lettuce contains 105 percent of the daily value of vitamin K, while romaine and butterhead have 85 percent. Green leaf lettuce also delivers 10 percent of the recommended daily intake of vitamin C, which is twice the amount in romaine or butterhead lettuce. Iceberg has 3 to 7 percent fewer B vitamins.