You may very well lose weight if you follow a diet consisting of lots of fruit, water etc - but that weight is likely mostly fluid, easily put back on again.
People often talk about feeling healthier having followed a "detox" regimen, but that is more to do with calorie restriction than anything else.
If you want to feel better in the short term, and help your body out - Sleep more, exercise more, quit or avoid smoking, drink less, eat less, eat and drink healthier.