Make sure you get a letter or some such piece of paperwork from the CAA stating that you've lost your medical purely on the grounds of weight/obesity.
This will enable you to qualify any box you might have to tick in the future which answers the question as to whether you've ever failed a medical.
Then go and lose some weight, perhaps 10 Kgs or three month's dieting?
You could of course just go and sit on a couch for ten weeks or so and let the muscle turn to fat?
http://www.nhlbi.nih.gov/guidelines/obesity/bmi_tbl.pdf