For healthy adults, digestion of food usually takes between 24 and 72 hours. After you eat, it takes about six to eight hours for food to pass through your stomach and small intestine. Food then enters your large intestine (colon) for further digestion and absorption of water. Elimination of undigested food residue through the large intestine usually begins after 24 hours. Complete elimination from the body may take several days.
As far as you question regarding the digestive timeline for protein, fat, and starch I was not able to find very good estimates. This is due to the fact that the digestion rates can very based on the components of a given meal. Generally speaking, carbohydrates tend to spend the least amount of time in the stomach, while protein stays in the stomach longer, and fats the longest. The time it takes to metabolize carbohydrates depends on the type. Simple sugars are metabolized much faster than more complex carbohydrates. For your reference you can view the following website.
Digesting Time for Some Common Foods Green Vegetables (non-starch) - 5 hours Raw Juices-15 minutes
Fat-12 hours Protein (meat)-12 hours
Protein (starch)-12 hours Protein (fat)-12 hours
Starch-5 hours Mild Starch-5 hours
Fruit, Sweet/Dried-3 hours Fruit (Acid)-2 hours
Fruit (Sub-Acid)-2 hours Fruit, Sweet/Fresh-3 hours
Melon-2 hours Syrup, Sugar-2 hours
Click Here to return to the search form.