Use the tried and tested technique of one less pie-a-day. No exercise required! The key is to only eat what your body needs. If you're sitting on your arse all day then you only need around 1600 cals. If you’re a keen exerciser you can bump that upto almost 3000. I cut out beer and alcohol and lost over a stone in about 2 months and have never put it back on again.
But now I pretty much never drink. No big loss for me though, but it really depends on if a) you're serious and b) Ok to lose something that you love to eat/drink.
That first part is not entirely true though. Your body will get used to a calorie amount and adjust accordingly. I started weight training at 19 years old weighing 60 KG's,ate like a mo-fo for years, all good by the way. Roll around to my 30th birthday I was 95kg's and in good lean shape (not show condition. but very near) since taking years off training and resuming very light weights (all due to injuries, mostly Delt I might add)
I now hold 90+ kgs 9 (in a lot worse condition mind you, not that tight at all)and have done so for over 2 years, yet I eat under 2000 kcals a day, that is way under for maintenance of a 5ft:11" 38 year old weighing in at just over 90kgs.
I agree with the chaps though, stay away from it, 4 stone is not a huge amount to shift as long as you put some effort in.
Well It worked for me
I'm an office worker, and my exercise mostly involves me moving my thumbs in an evening or sex (although i hear thats a good calorie burner?). I'm 5'10 was around 89kgs (just over 14 stone) and had been for about 5 years. When i was 30, just cut out chocolate, crisps and beer just stuck to 2 meals a day and water and dropped to 73kgs (11.5 stone).
And now 2 years on I’m still steady at that weight, and now my body is used to it I don't feel hungry at all anymore.