If you want to increase your intake of vegetables, try juicing them (don't cook them).

Everyone's rate of digestion...or transit time...varies. You can get a general idea of your by eating a bunch of beets and then watching for color change in your stool. Also, different types of foods digest at different rates...fruit digests very quicky and meat takes longer...one reason that it is not advised to combine fruit and protein in the same meal.

And different foods effect people differently....some (like myself) digest meat very well...others do better on a vegetarian diet. You have to pay close attention to how your own body responds. The same holds true for carb intake. You might be interested in reading The Metabolic Typing Diet....Dr. Mercola talks about it on mercola.com, too.

As for veggies...you'll get maximum nutrients and enzymes by eating them raw. juicing is also an excellent way to consume veggies. An all-raw food diet can be difficult for some people with compromised digestive funtion or may not be preferrable. Eating cooked food should then be combined with raw foods and or juices in the diet.

As PTree said, the rate of digestion is different for everyone, but I remember reading (in "Fit For Life", I think) that a properly combined protein meal takes aprox. 4 hours to digest.