Welcome Nathalie to The Best Thread on Mumsnet™! 14 by the end of Jan does sound do-able, but you'll have to be pretty careful around Christmas, so you might be best off aiming for as much as possible before the festivities start, then just focusing on maintaining as best you can, then really go for it in Jan, just so you don't get demoralised. We'll all be in the same boat 
Well done Gower and TV, and congrats on the black belt Kiki!
koko definitely don't back away from the thread - as BOOP says you'll feel worse and it'll get harder and harder to get back into it. What is it that you tend to binge on mid-afternoon? Is it generally at home or at work? If it's at home I think you need to:
Purge everything from the house
Schedule - and I mean with telephone alarms - a healthy snack at the "danger hour" (i.e. a peppermint tea and a rice cake with peanut butter, or whatever)
If possible, schedule a distraction from snack time to dinner time.
If you can do that for a few days in a row I'm sure it'll get much easier.