Diet soda gets too much hate. I think dropping diet soda if you want to optimize health is a great thing, but it could be a great stepping stone for those with a non-diet soda habit.
It might also be easier get to seltzers with diet sodas in-between
I've been doing intermittent fasting for a few months now. I've had trouble with cardio since I hurt my knees running, and gained nearly 20 pounds since I found it hard to get to the gym to do cycling or something else. I also noticed my appetite increasing, not sure if it it was due to new medication I was on, but I was eating three meals a day and snacking a lot more.
I was surprised how easy it was to transition to IF. I had a few hunger pains before lunch after doing it for a few days, but after a week or so I felt fine. I do a loose 16:8, sometimes it's more like 14:10 and other times it's closer to 18:6. I try to make my lunch a shake of Huel that I finish over the course of an hour, sometimes more. I put about 500 calories worth in there, and have a 200-300 calorie snack (usually trail mix) right before I leave work. For drinks I may have a beer or two when I get home, but it's usually water/coffee/tea/seltzer if not. I lost the added weight very quickly, and am back around the weight I was when I was running ~15 miles every week. The ancillary benefits are great too, I find my energy is more level during the day, it requires very little meal prep, and I spend less on food. I went from spending 10 dollars or so each day on breakfast and lunch, to about 3 with the one serving of Huel. And even when I cheat a little on lunch, or eat earlier than normal, I need a smaller portion to be sated.
I'm trying to get my girlfriend to try a variation of this, but I know there are some different concerns for women. She just keeps trying strict-ish low-carb diets and then cheating with snacks/ice cream after dinner, or when she's working from home. It's a sensitive issue for her (she's had an eating disorder previously that hasn't fully gone away) so I'm trying to tread lightly. I don't notice a huge difference from when we started dating, but her self-confidence has definitely gotten lower and I wish something like this would work well for her