Final answer:
The stomach emptying time after ingesting food on an empty stomach can range from 2 to 6 hours. Carbohydrates progress quickest, followed by protein, with fats taking the longest. The full digestion process completes in about 24 to 72 hours.
Step-by-step explanation:
When considering how soon a substance taken on an empty stomach will reach the small intestine, it is important to note that the emptying time of the stomach's contents varies depending on the type of food consumed. Carbohydrate-rich meals tend to move through the stomach more rapidly, usually within 2 hours. In contrast, meals high in protein have a slightly longer stomach residency time. The longest stomach emptying time is observed for meals with high fat content, which could remain in the stomach for up to 6 hours, as enzymes in the small intestine take longer to process fats. The complete digestion process, from the stomach to the final absorption in the intestines, typically takes about 24 to 72 hours.