Your intent may have been to say, "the combination of all these ingredients in a diet soda are not good for you", but what it reads like is that you are specifically calling out each individual ingredient as individually not good.

And yes, it would have been much clearer if you would have said something along the lines of "ingredients in diet soda like X, Y, and Z are not good for you while leaving out something as benign as carbonated water from the list.