It is a good idea to cleanse your body of some of the dodgy stuff. The best detox is fruit i think becasue it is essential that during the detox you still get the needed nutrients for your body. I also assume that eating fruit would give you much less calories than your used to so this would help in losing some weight.
the thing to remember bout weight loss is that is can not be done too fast. Starving your body of fuel will cause it to store food as fat, somewhat a survival mechanism. keeping your metabolism going with fruit will be a good start.
Once the detox is over start a all natural eating plan. only vegies fruit and meat that has not been processed, no packages. this will make so much difference to how you feel due to less preservatives, added sugar etc. it will also keep you on track for the goal you have.
good luck