Hiya,
I've gradually lost 5st 2lb since last August by halving my portion sizes and allowing myself one treat per day.
I've also not beaten myself up about the odd slip up either... and just started the next day with a new outlook. I've made sure I've had breakfast, lunch and evening meal too... I was always really bad for missing both breakfast and lunch - I've had to force myself to eat these meals; now I can't do without them!!
I don't snack between meals... and if I am hungry I usually have some fruit.
I've mentioned this in my post in 'Introductions', but I also found that reading has helped me stay out of the kitchen cupboards.
I don't have a very active life outside of work (no kids or family close by), so aside from taking care of Hubby and the dog, I used to get bored very easily and that's when I hit the cupboards.... and coming home extremely hungry from work didn't help.
I also don't buy crisps, chocolate or biscuits anymore.... but Hubby has his own stash, which I strictly stay away from!
I found that making a mental note of what I've been eating through the day really helps... and when faced with someone in the office offering me a slice of cake, I ask myself 'Do I really want this now, or do I want my treat when I'm at home tonight in front of the telly?' Invariably I want my treat when I'm relaxing in front of the telly... so I'm finding it easy to say 'no' to the cake mountain which always appears at work.
Its difficult, but it becomes a way of life... you get used to it, and people get used to you saying 'No' too - and it makes me feel quite proud of myself that I do say 'No'. I'm looking after 'me', taking a stand for myself and I feel so much stronger for it.
What I would say is... don't beat yourself up about it... still go and have meals out; just eat half of what's put in front of you - even the dessert! We're all allowed treats, don't deprive yourself, but just think about the balancing act you need to do.
Good luck, you can do it!

x