You can very easily do a Colon Cleanse and go about your regular routine...you need not fast in order for it to be effective...and it usually involves less cleansing reactions than other types of cleansing. Psyllium and Bentonite or Holistic Horizons program are two of several options for you. If you start with a thorough Colon Cleanse it can make any successive cleansing that much easier because the toxins have a more direct avenue to rapidly exit the body.
Liver Flushes can also easily be done on a weekend that should give you enough time to recover...and a parasite cleanse can be done anytime...although die-off can make you feel crummy if you have a problem with parasites. Then again...if you have a problem with parasites chances are they are already compromising your health and energy and you need to get rid of them.
Actually some people who fast are even able to maintain their normal life...and have more energy and clarity than ever. You can never know for sure until you've tried it...and you might be very surprised at how you respond.