Lose the fast food. At the very least eat it very rarely (say once a month). Aim for drinking more water or juice as opposed to Pepsi or other sugary drinks.
Also, don't eat anything late at night, give yourself a cutoff time in the evening of at least 3 hours or so before you plan on going to bed.
Keep up with the exercise and be patient, it'll be some weeks before you see results (or other people notice them) so don't get discouraged.