A month may be too soon to expect visible results.
Suggestion on the cycling, use a heart rate monitor so you can view effort versus speed (which can be deceiving as to how much of a workout you're actually getting). Vary the types of rides it up a bit so it doesn't get boring. Ride with people slightly faster than you so you push yourself. Do hillwork so the tendency to slack lessens.
The more you ride the more you will lose weight but try not to accomplsih too much too soon as you may burn out (and then not workout at all).
I was never good on the food angle. Cycling has naturally curbed my eating habits (and the kind of food I eat) but I would say that I pretty much eat with the same gusto. More miles and intensity helps me burn it off though.
Bottom line, don't worry it will pay off.