I'm a moderator on a fitness and nutrition forum.
Just so you know, a 'lemon detox diet' is nothing more than fasting. Its not healthy, doesn't actually detox, and any weight lost will be water weight and lean muscle mass, not fat.
See, muscle mass, beyond what you need to move, isn't an advantage to survival. So the body breaks down the muscle to create glycogen, while producing ketones, and will do everythign it can to preserve fat, since that's long term energy.
only when you waste down muscle to an extreme amount will the body start burning fat...by then you're starved, sick, weak, and in a bad mood.