My cousin lost 35 LBS in 3 months by exercising 45 minutes 3-4 days a week and going on the Low Glycemic Index diet. I'm about to start it. General rule, stay away from soda - any kind. Drink at least 3 liter water bottles a day and drink tons of green tea.
ETA: Here's a link to the diet plan
http://www.lowcarbiseasy.com/menuplanlowgi.htm#19
<em>edited by delicatesting on 22/04/2011</em>