Not to mention you will sleep a lot better!!!
I am\was in the same boat as you. Besides gaining weight, I also thought that I could go to sleep at night with no problems. Sure, I would "go to bed" but after I laid in bed for 45 minutes I would finally go to sleep. That is if I did not have any types of anxiety issues. I thought this was normal behavior because I have been drinking Pepsi like water for my whole adult life.
Now that I have quit all caffeine, I am astonished at the difference! First off, going to sleep takes all of about 10 minutes. Secondly, no more anxiety attacks! Words really can't describe the difference. It is wonderful to go to bed and actually fall asleep.
I am amazed how many people say "Oh, I can drink 13 cans of soda a day and go to sleep with no issues". I have friends and family that were prescribed medication to sleep. One of them was actually taking the sleeping pills with Pepsi! I tell them about my changes and they blow me off like I am crazy!
I was able to convince one of my friends that I really was not crazy and this would would help. I let her know that she could drink all the caffeine she wanted up till 12:00pm, but after 12.. that was it. It sucks for a few weeks, but after that she was just like me.. WOW I can not believe the difference. Sleeping like a baby now!
Bottom line.. If you are like my other asshat friends and think you can drink soda and go to sleep with no issues... You have no clue what you are talking about!