I drink tons of diet soda. And I’m thinner, and I used to weigh 110 pounds more, and at that time I was drinking regular soda instead. I can’t attribute all of the 110 pound loss to switching to diet, but it helped.

However, Dr. Drew always says there’s no such thing as a free lunch in nature. Even medicines and pharmaceuticals all have some type of side effect. Maybe you are helping your blood pressure but you are becoming more dehydrated for example.
There has to be some side effect of drinking that much of anything that isn’t water. Is it worse than just having the sugar from regular soda? It depends on the person... but something has got to be impacted, whether it be kidneys, cravings, or what.