I was going to suggest a delay tactic too - I've heard people ("experts!") recommend that, when you want to eat something, tell yourself you are going to wait for, I think, 10 minutes. If after that time you still really want it, have it. But the idea is that the delay can work and make the desire pass. There is apparently science behind it....something significant about it being (I think) a 10 minute wait but I can't remember exactly. Presumably, the idea is also probably that you try to distract yourself during the wait time too...not that you just sit there obsessively counting down the minutes until you can have a few hobnobs ;-)
And I agree with
@ghotiff about consciously trying to break up any habit/ritual that has been created around certain activities eg the journaling. What new ritual could you choose to put around it instead that might help with that?
Also, yes, you could try replacing food with fluids. Knock back water (infuse with fresh lemon and lime/cucumber/mint/berries etc to make it more interesting! You could see if hot drinks create a more/less satisfying sensation of "fullness". I guess the potential pitfalls that you might want to avoid with hot drinks are increasing sugar levels (if you take sugar in you tea and coffee or if you're thinking of hot chocolate/malty drinks) because that won't be great if you want to lose weight. Also - if you up your tea/coffee intake, you might want to be mindful of increasing your caffeine intake. Of course, there is decaf tea and coffee plus herbal and fruit teas :-) Do you like drinking hot water? I find it very soothing and it's really good for your digestive system. Might be worth a try. Carbonated soft drinks may help you feel more full. Sparkling water the healthiest option. Cola/other fizzy drinks probably not so healthy, but you may still consider them better than unhealthy foods, I don't know? You might feel too bloated if you drink too much gas though...!
I know you said exercise doesn't really help. You could perhaps try a delay tactic of going for a walk? So, you fancy eating whatever and you decide to go out for a walk and to listen to some music that makes you feel good or an audio book while you walk, to focus your mind on something else and put physical distance between you and the food in that moment. Doesn't have to be a long walk or a power walk.
If you have the willpower for it, you could commit to going cold turkey on sugar. Not full-on, hardcore completely giving up all kinds of sugar, but really cutting down on very sugary processed "treat" foods and drinks. You'll probably have a rough first few days and get some withdrawal symptoms (headaches, lethargy, moodiness, cravings etc) I find that if I last the week that seems to get all the sugar out my system and then the cravings just stop and I really don't especially want sweet things then.
Don't know if this makes any sense at all but it popped in my head so I'll just add it to the mix - do you think there's any way that you might be able to replace the "fullness" with something non-physical? So, can you feel "full" in other ways? What else "fills you up"? Doing something creative? Being outside in nature? Stroking an animal? Laughing? So, filling the emotional need without physically filling your body?
As an aside, though I think it could still be relevant to you - I realised only fairly recently that I generally had no idea when I was hungry or when I was full...I only really registered when I felt starving (because I'd gone a day without eating) or when I felt really uncomfortably full (eg after a really massive blow out meal like Christmas dinner or something). This realisation emphasised for me how disconnected I am from my body most of the time. I read Susie Orbach on Eating and found that really interesting...it really made me think about how and why I eat and it shifted a few things for me. I made some very simple changes in habit after that and lost quite a lot of weight - through conscious eating rather than dieting or depriving myself. Something in that book just sort of clicked for me and made me think about things a bit differently.
Good luck! It's great that you're choosing to look after yourself :-)