I am around the same weight goals as you (164-145), but I am a little shorter (5’6”) and older (44). 16:8 just doesn’t work for me unless I am super-strict on counting calories, but I have found that I am too lazy to count calories. The thing that works best for me is 23:1 with some 20:4 thrown in.
I know you said its hard to shorten your window but I think you may need to if you want faster results. If you are opening your window at 2 pm could you close at 8 pm? That will get you from 16:8 to 18:6 and you may sleep better on an empty stomach (I do)
The other option is to try and move your window to a different time of day (mine is 12-4) before your work shift. I know it’s hard to get used to not eating socially - that’s the hardest part of IF imho.
A jump up on the scale like that is likely temporary. Good luck
I find that sometimes you need to make sure you’re getting enough calories, or your body goes into starvation mode. I’ve had months where I lost nothing. Because I was working out too hard and having like 1600 calories a day I was also 350# at the time. When I moved it up to 2000-2600. I started losing weight again. IMO Ideally you want to lose weight slowly so your metabolism doesn’t get too used having way too few calories. I think Thomas Delauer on YouTube talked about it.
It could also be a thyroid issue, maybe talk to a doctor to eliminate other causes. Good luck.
My next suggestion would be to extend your fasting window- 18:6/20:4/22:2 (even OMAD) and eliminate alcohol and reduce your carbohydrates, at least for now. The types of foods/beverages you are consuming are critical to your success.
I never had much success with IF with regards to weight loss. I found it worked better for maintenance and reducing binge eating. You can still theoretically consume your daily energy needs within the 8 hour eating window.
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With weight loss, I do alternate day modified fasts, consuming vegies and a few water protein shakes during the fast. It keeps hunger pains really low. Whenever I get the grumbles, I’ll just eat a tomato or two and it goes away. :) So far I’m down 6.5kg (14 lbs?) after 26 days.