The solution: A lapse isn't a collapse!
Just get straight back on track with healthy eating.
If allowing yourself a small portion of your favourite indulgence is too hard,
you may need to keep foods that are a weakness completely out of the way for a while.
You need to eat over 12 Mars bars (3500 calories) to put on 1lb of fat. So one bad day isn't going to spell disaster.
A lapse isn't a collapse!