1.Zero calories means zero nutritional value. The typical ingredient list on a diet soda reads something like this: carbonated water, aspartame, potassium benzoate, phosphoric acid, citric acid, caffeine, caramel color and natural flavors. Is there anything there with any nutritional value? No. Not only that, artificial sweeteners, like aspartame, have been linked to cancer (in some studies).
 
2.Drinking only diet sodas doesn’t mean you will lose weight. This seems like a contradiction, but bear with me. When you drink a diet soda, your blood glucose levels rise because of the artificial sweeteners. However, since diet soda has no real nutrients, or calories, there is nothing to satisfy that spike in blood sugar. This leads your body to look for nutrients (specifically sugar) in other foods. In other words, when you drink a diet soda you are much more likely to reach for the ice cream you’ve been saving in the freezer than if you just had plain coffee, for example. Another common reaction to drinking a diet soda is purely psychological. People think: “I just had a DIET soda; I did good. I guess I deserve a hamburger and a large order of fries.” Wrong. Translation: “I just pumped my body full of artificial sweeteners and other damaging chemicals. Now I deserve some trans fat and a large amount of sodium.” Diet soda will do that to you. Stay away from the stuff.
 
3.Diet soda is a diuretic. You may be thinking: “Wait, coffee is too, and you said it was good for you!” Absolutely. If you drink coffee, you need to drink a lot of water. But coffee has anti-oxidants; It is natural, and it will boost your metabolism, not cause a sugar crash. When you drink a diet soda your body will immediately start losing water and calcium, which you must replenish. Contrary to coffee, it has no positive effects on the body to counter the fact that it is a diuretic. Since you might not be getting enough water already, you don’t need to make your body work harder by drinking soda.
 
4.Carbonation isn’t good for your body. I’ll be honest: I have no studies to back this up. But give me a chance. Here is my logic: when you’re running, you are taking in oxygen and expelling carbon dioxide. We know carbon dioxide is toxic for our bodies. So why would you want to drink something that has carbonated water? It just seems counterproductive.
 
So what do I suggest? Well to begin with, drop sodas completely, pick up a healthier habit like coffee, tea or, even better, water. If you absolutely must have a soda, I would go so far as to suggest you should just go ahead and drink a regular one. This way you will avoid some of the empty calories and satisfy your body somewhat, so as to not eat other unhealthy food later. Additionally, I’m not criticizing those who do drink diet soda. I’m just suggesting you stop.