Trying to diet can be an extremely disheartening venture and trying to avoid temptation is night impossible, particularly when you have been a chocaholic for all of your life. The first step to a proper diet is working out your BMI and how much weight you could do with losing.
If your BMI is quite low (below 24) you might find it harder to lose weight and at a slower rate, however if it is high, you should see more substantial weight gains within a few weeks. It can be upsetting to hear of people losing 4 stone in a month; however it is likely that such people were larger in the first place.
One of the simplest parts of dieting is simply cutting down your portion size you can still eat a lot of the foods that you love, just in smaller sizes. This will cut down the number of calories that you take in and make it easier to lose weight.
You should also try and exercise more often, balancing cardio and toning the cardio will help you to expend calories whilst the toning will give you a firmer look, so even if you have gained a bit of a belly, you can reduce your measurements and have a firmer body overall.