text: keeping yourself thin thru dehydration is never a good idea. 10 lbs. of water weight is almost in the "severe" category which can have extreme negative effects on body's chemistry, potential kidney failure and much more.\n\nIf  the 15lbs weight is purely fat you need to lose it the old fashion way, low impact cardio 5-6 days a week 45 min+ , a low glycemic(sugar) and fat diet with lots of veggies and healthy fats.\n\n use an elliptical machine,rower and high speed circuit weights to protect those knees.\n\n If none of these help, check with nutritionist about fasting as you may have toxic bloating.