I don't do diets, just lifestyle changes, and I never associate them with a New Year resolution. It's clear to me as we come up on OMG there's no room in the gym because of all the New Year resolution people are here and that the fact that things will be back to normal by mid-February, that this practice has a low probability of success as far as lifestyle changes. I think this happens because people aren't looking at it seriously as a lifestyle change and instead just something to get to some arbitrary goal like a specific weight.
I was just thinking the other day as I left the gym, 8 years into never missing more than 2 weeks, sore, and feeling a little depleted, how different I look at it now vs 10 years ago. I have no goals that represent some point at which I can stop. I used to set specific goals like I want to bench 225 for 4 sets of 10 and think I'll reach that and then just "cruise" there. Then I'd get there and the new goal just became 235, then 245, 255. Then I stopped thinking about it in terms of what I needed to do to get to a point where I can stop or cruise and this evolved into the goal is just more, always more. Not just heavier weights but sometimes it means working on athletic ability or stamina etc. In the end, it really is just to keep going and doing it.
So my recommendation is to make a lifestyle change. You can set some arbitrary weight goal but don't get caught up in doing extreme things to get there with ideas that once you reach it you're good and can just go back to what got you there. Set realistic lifestyle changes in motion with the goal of continuing them forever, regardless of weight or your mini goals.