Final answer:
The meal that spends the most time in the stomach is the soluble fiber-rich diet (Option B). This is because soluble fiber forms a gel-like substance that slows digestion, unlike insoluble fiber, which aids in quicker digestion.
Step-by-step explanation:
The soluble fiber-rich diet spends the most time in the stomach. Soluble fiber dissolves in water to form a gel-like substance, which thickens and slows the movement of chyme through the small intestine.
This process slows the absorption of glucose and delays gastric emptying, leading to a more extended feeling of fullness.
The presence of fermentable soluble fiber in the diet promotes this slower digestion due to its viscosity and potential to be fermented by bacteria in the digestive tract.
In contrast, insoluble fiber has a bulking action but does not form a gel and is not readily fermented.
It aids in regular bowel movements by adding bulk to the stool and promotes quicker passage through the gastrointestinal tract.
A standard diet without a high volume of fiber is generally more rapidly digested than a fiber-rich diet.
Therefore, Option B ('The soluble fiber-rich diet, because fiber slows digestion') is the most accurate choice based on the information provided.