I used to drink quite a few Pepsis, like at one point I was on 6+ per day. (cans). My dad is even worse than me, and he kept trying to quit cold turkey and got back on it. Watching him trying to do that did open my eyes and made me realize I need to slow down on it too, but I really don't believe in quitting something you like completely, if you really think you can, all the power to you, but I figure if I can at least reduce to 1 per day I'm way better off. So that's what I did. There is nothing more relaxing than sitting down at the computer with one. I guess it's like smoking, it's really a habit.
But then I discovered Club Soda. It's essentially carbonated water with some flavouring. Zero calories, and barely no ingredients. No aspartame or anything like that, just a bit of sodium and think phosphor or something, I forget. (not acid). So now I drink those instead of Pepsi and have a Pepsi or other pop only once in a while when I get a real craving.
That said if you can quit completely then even better. Some people can't have just one, they need more. Kinda like smoking, you pretty much have to eventually quit completely.
In general though I really need to watch my diet more. I'm much better than I was when I first started to live on my own but still eat lot of takeout, it's hard to know what to make when you live alone. Most recipes are just too complex and time consuming for one person so you end up doing the simple and less healthy stuff, like waffles, pop tarts, etc. Spegatti, fish and chips, chicken and other stuff arn't so bad, but that's just a few meals, so still need other stuff in between and it's not all good for me.
A few months back I had this really weird episode where I was constantly hungry. I made bacon and eggs, and I was still hungry after, so I made toasts, was still hungry, made spaghetti, was still hungry, ate a whole bunch of fruit, nuts etc, was still hungry. I went to Wendy's and got a Baconator with large fry. Was still hungry. It was ridiculous. This went on for a week. Actually ended up going to the ER because I did not know WTF was going on. First thing that kept coming up on Google was pregnancy or diabetes. I'm a virgin male so I knew it was not pregnancy.

ER doc thought diabetes too, tested my blood sugar but it was good. Ended up having to see my family doc but only was able to get in like 3 weeks later and by then the issue was mostly gone. The issue of always being hungry turned into a burning sensation in my chest and just feeling really crappy then that slowly just dissipated.
When I explained the whole thing to my doc he said it was probably heart burn. But all that said, it was a huge wake up call for me. The remote possibility of getting a diabetes symptom kinda opened my eyes to really seriously look at my health even though it was not that. Personally I think it was some kind of stomach virus or something that I caught and it just had to run it's course.
While my diet is not perfect the main things I do try to avoid now are sugar, and somewhat fats/carbs. There's lot of studies saying fats are not so bad now, I'm skeptical considering it's usually associated with heart issues (which also run in the family) but I have yet to hear any study say sugar is good, so I really try to cut back on that. Liquid sugar (ex: pepsi or even fruit juice) is probably the worse of all. That's 40 something gram, going directly into you with little to no processing required by the body. At least stuff like candy and especially raw fruit require the body to work a bit so it's not quite as bad.
My biggest weakness is poutine though... I had like two this week. Wow did not realize I made a wall of text.