Try the south beach diet and 200 minutes of cardio a week with 60 minutes additional of weights

Don't eat too little- your body will store the fat and eat the muscle, thinking it's in starvation mode.
Make sure you drink plenty of water, eat lots of fruit, and if your schedule allows it, eat 6 mini meals a day instead of the big three.

Eat only when hungry. Eat not more than three times a day unless u r diabetic. Eat nourishing food with plenty of fresh fruits and vegetables being part of it. Chew each morsel at least 32 times. This will activate signal to the brain as soon as u have had enough. Besides this change in eating style, take regular light exercises and brisk walks every day. U will be able to gain/shed all extra weight gracefully and in a reasonable time span.