Some sodas have medicinal effects. I have a genetic disorder, so my diet is absolutely not the root cause of my health issues. I was diagnosed late in life. That empowered me to finally start getting healthier. With getting healthier, I consume less diet coke.

A couple of excerpts from my food blog:

I basically live on diet coke. Coca cola products contain extract from the coca plant. This has medicinal benefits. No other cola products have this. Other cola products tend to be mostly sugar water -- though I do sometimes drink ginger ale because ginger helps with nausea.

http://miceats.blogspot.com/2016/09/diet-coke.html

Plain water has been gradually creeping into my diet here lately. This is noteworthy because I rarely drank plain water for quite a few years.

http://miceats.blogspot.com/2017/01/plain-water.html