Does a colon cleanse and fasting actually have health benefits?

I am thinking of taking a trip to a Thai spa and having a colon cleanse. Not the silly fifty pound health juices, I want to do the whole kit kaboodle. If it works.
It says that the colon is the ‘root of all disease’. I seriously doubt this, but then again I’m not a health professional.

So: does the colon cleanse actually work with health benefits? And does the whole fasting – raw – food jam work?

Thanks!
I’m centring on the colon bit – I know some people say it’s rubbish, but is there any sorta scientific proof?