You are best talking to a nurse at your local GP surgery who will encourage you to do a food diary ( a must if you want to loose weight ) I would suggest doing an exercise/activity diary alongside it too.
I started this 2 months ago and as a result I cut out drinking apart from 2 pints on a sunday as a reward. I eat a lot of fruit esp when I feel peckish as I grab an apple or clementine. I have also started to do a little food combining where I dont mix protein and carbs, so its veg and carbs or veg and protein. Occasionally I get a craving for something I shouldent eat and I let myself have a chocky bar (milky way or something not too bad) or a pack of crisps. It stops you having a mass pig out session after 3 weeks of deprivation and constant cravings. Also I have celebratory meals sometimes such as pizza or fish and chips esp after weigh-day when I have lost more weight.
I have upped the exercise but to be quite honest that is mainly anerobic exercise which is mainly for my job and has little fat loss benefit. Low intensity exercise such as a gentle cycle or a brisk walk to work instead of the car is much more beneficial to weight loss as it keeps your heart-rate around the 60-70% mark.
So far in 2 months I have lost 10KG (22lb or 1.57 Stone) not much less than your mate who, once he reverts to a normal diet, will pile it all back on and maybe more! This method is aimed at lifestyle change which will keep the weight off for longer if not for good.
Oh and make sure that you weigh yourself on the same day and time every week otherwise you will get disappointing variations which will demoralise you and confuse you as to how well you are doing.
Good luck
