There are several ways you can determine how long it takes for food pass from through your body (your elimination time), which is an indicator of good colon health.
One popular method is to eat beetroot (the whole beet not just the juice!) – make a note of the time and keep an eye out for them to appear in your stools – your stools will turn a distinct beet-reddish colour. Don’t forget you are doing this experiment and panic that you have seen blood!
A health colon has an elimination time of 18-24 hours, however bear in mind that if you have eaten a big fat steak before doing this – you may slow this down a bit.
If you are a raw food loving vegetarian things might move a bit quicker for you and the intestine is a tube and this experiment isn’t conducted in isolation (unless you want to make your self very hungry! I know I don’t).