Re: ~ 100 oz. of soda per day: Long-term effects?
Too much caffeine has so many bad effects it's impossible to list them. If you don't have one of your huge sodas during the day I bet you get a headache and feel cranky and listless...right? That's withdrawal symptoms. Plus the fact that you say you need then in order to "feel decent". That's a form of addiction to the caffeine and sugar.
All that sugar can cause insulin resistance which can lead to diabetes and weight gain.
Also, not drinking water, plain old water, can cause constipation and damage to your colon due to being dehydrated. Do you ever wake up feeling like you are hung over, even when you didn't drink any alcohol? That's dehydration. You need water in order for your body to function properly and digest your food well. Many people have waste in their systems that sits there for weeks, causing all kinds of digestive issues that you don't feel until they are really bad. That waste needs water to move along.
You are going to have to wean yourself off all that caffeine and sugar if you want to improve your health and reduce the risk of diabetes and colon issues. Be prepared to feel icky for a few days, even a few weeks, but after you get off that caffeine and sugar you are going to feel fantastic.