Give it a good trial week with about 5 sessions to get your bowel cleared. If you are seriously impacted one or two will not be enough. colonics are not the answer but they are a good start.
At the same time you want to give up any refined flour, bread, cakes and those croissants. These stick like plaster to the colon. Also dairy products produce mucus so you have a good recipe for glue in your system.
Take probiotics. You need the good bacteria for digestion and good bowel movements.
You need lots of fibre. Take a teaspoon of Psyllium daily in a glass of water, followed by another glass of water. The Psyllium is good for constipation or diahreah. Drink at least a litre of water every day.
You also need the good oils for lubrication. Olive, flax etc., Udo's choice is a very good oil mixture with the Omega 3 and 6. Take a tablespoon at least, every day.
Exercise daily. You have to move your body physically to get rid of stagnation and get the system moving. Massage your stomach also, in a clockwise direction.
Castor oil packs will help. You can find instructions on this site.