Final answer:
A healthy body typically absorbs about 90 to 100 percent of the carbohydrate, protein, and fat in a meal within about 24 to 48 hours of eating, the exact time can vary based on meal composition and individual digestive efficiency.
Step-by-step explanation:
A healthy body digests and absorbs approximately 90 to 100 percent of the carbohydrate, protein, and fat in a meal within about 24 to 48 hours of eating. The small intestine plays a critical role in the absorption of these macronutrients. The breakdown of carbohydrates into monosaccharides such as glucose and galactose allows for efficient absorption, with the small intestine capable of absorbing monosaccharides at an estimated rate of 120 grams per hour. Proteins are reduced to their constituent amino acids for absorption, and lipids, such as triglycerides, are also digested and absorbed within this timeframe. The exact time can vary depending on factors like the composition of the meal and individual digestive efficiency.
Indigestible fibers are not absorbed and are eliminated in the feces. It is important for health to maintain a balanced intake of these nutrients, with recommendations often suggesting that 10-15% of total calories come from proteins, 20-30% from fats, and 50-70% from carbohydrates.