Numbers Game: Answer

A 2007 study published in the Academy of General Dentistry's General Dentistry journal reported that colas' -- both regular and diet -- enamel erosion potential is 10 times higher that of fruit juice.

What does this mean? In essence, it gives another reason to think of sodas -- diet or not -- as occasional beverages, rather than daily staples.

Turns out the citric and phosphoric acids in sodas wear out our enamel, the protective substance covering the crowns of our teeth. Over time, constant attacks on our enamel lead to tooth decay.

What's crucial to understand is that the lack of sucrose (table sugar) in a soda does not mean it is automatically safe for our teeth. If you see phosphoric or citric acid listed as an ingredient, my best recommendation is to consume that drink with a straw. That way, the liquid goes straight to the back of the throat, reducing our enamel's exposure to it.

Taking tap water as the benchmark (which has a very neutral pH of approximately 7.6), here is how some popular sodas measure up:

Cherry Coke: 2.52
Coke: 2.53
Pepsi: 2.53
Dr. Pepper: 2.9
7-Up: 3.2
Diet Coke: 3.29
Root Beer: 4.0

I do want to point out that a few fruit juices -- such as grapefruit, with a pH similar to Dr. Pepper -- also have the propensity to attack our enamel. However, the vast majority (when fresh squeezed and not loaded with sugar) do significantly less damage on our enamel.