Well if by slowing down you mean you're only losing 30 lbs every 4 months, know that that is still amazing progress! Your body needs time to readjust to major changes you're making, so it's not odd to hit plateaus. Your body is trying to readjust the amount of skin it carries, the amount of electrolytes it needs to take in, different hormones, your bones and joints probably have some amount of chronic fatigue that they need to recover from.
When starting from 400, (I don't know your build but assume you're aiming for the 150-200 range.) expect to reach 300 only after consistently eating well for 10-14 months.
Take this time to build good habits. I remember those cravings, and I still get them from time-to-time, but I mitigate them mostly through a few things:
1. I don't allow them in my house - I have one exception, Peanut butter, which I think is a weakness of mine, I try to limit my intake, and it's addictiveness has been studied.
2. When I have a craving, I meditate on certain statements:
"That junk makes me feel bad."
"That junk does have the nutrition I need."
"That junk does not have power over me, I decide what I eat and what I put into my body"
About 4-5 years ago, I quit soda. In the first 2-3 years of that, I maybe had a soda once every 3-4 months. Then it eventually turned into once or twice a year. Now, I can't remember the last time I had one. Each progressive soda I've had, just tastes worse to me now, or I have my fill after about 3 or 4 sips. And I decided to stop letting my mind tell me "Oh but you shouldn't waste it since you got it.". It's sugar water it has little to no nutritional value, economic value, or happiness value. The same goes for basic white bread, rice, potatoes, and sugar. It's cheap, useless calories. Get in the habit of throwing it away in the trash rather than your body.
But like many others, I used to drink sodas/ eat candy regularly. You can retrain your mind, but it takes time. It takes effort, and it doesn't mean you'll be perfect. Good job so far, and I hope to hear of great results come 2019!