Swap all your unhealthy snacks for fruit. celery and carrots are good snacking veg as they have hardly any calories. watch your portion sizes, i think a portion should fit into the palm of your hand. walking is great exersice, its not to strenous, and you can fit it into your day, just by getting of the bus a stop early, not taking taxis (unless its unsafe to walk), walking to the shop instead of taking a car. run up anf down stairs instead of walking, and take the stairs instead of the lift or the escalotor, unless youre on the 12th floor or something!
i think a detox diet can be good for your system. but you need to be careful, dont do it for to long, and when you come of it, do it slowly, if you eat a huge meal straight after youve finished a detox, you might be sick. they can give your system a great kickstart for a diet, but if youre restricting a lot, then you might actually end up eating more as youre telling yourself you cant have anything nice.