-Safe way to clean out your colon? Health professionals?

VERY skeptical about this. But have had some symptoms.
My biggest thing is what do you eat after-wards. Fiber okay(more detailed exactly what)
No meats(red) okay
What about Lobster,Shrimp, Fish (Tilapiaa)

Raw veggies and fruits -Okay EXACTLY what Veggies and EXACTLY what fruits..
Smartazz out-there , no smartazzs comments or sarcastic comments
PPL please be specific..