Some foods are easiest to digest than others. Foods harder to digest stay longer in the stomach. Therefore, being longer in the stomach means that they actually sink to the bottom of the cavity before entering the large intestine, making difficult to the others to go through the normal digestion process.
If you check the picture above, the foods rich in fats are harder to digest, slowing the digestion and increasing the muscular contractions through your digestive tract. The strong muscular contractions cause recurring stomach spasms, bloating, shortness of breath, nausea and sometimes, vomiting.
The easiest foods to digest would be liquids, being water the easiest but anything with a high water content would be easy to digest. This means fruit and vegetable juices, light vegetable broths, most soups, etc.
Some vegetables digest in as little time as fruits, being leafy vegetables are the fastest digesting group in the vegetable family.
Leafy vegetables are the fastest digesting group in the vegetable family.
Milk products are even more complex than nuts and seeds. It has the particular ability to neutralize stomach acids, slowing down the digestion of everything else you eat with it. When added to a meal, it lengthens the time the meal stays in the stomach.
Fish is probably the easiest to digest of the flesh foods (meats) because of its low fat and low fiber content.
The more you mix proteins, carbohydrates, and fats, the more complex the meal becomes. For best digestion of an already complex food, have animal foods with vegetables alone and avoid starches and other types of protein. Multiple proteins increase the strain on your enzyme capacity and if you eat too much, can lead to enervation, fatigue, flatulence, and putrefaction.
Photo by Food Combination & Digestion’s book