1) Bubble trouble

When taken at face value, diet soda seems like a health-conscious choice. It saves you the 140-plus calories you'd find in a sugary soft drink while still satisfying your urge for something sweet with artificial sweeteners like aspartame, saccharin, and sucralose. But there's more to this chemical cocktail than meets the eye.

2) It could lead to weight gain, not weight loss

Diet soda is calorie-free, but it won't necessarily help you lose weight. Researchers from the University of Texas found that over the course of about a decade, diet soda drinkers had a 70% greater increase in waist circumference compared with non-drinkers. And get this: participants who slurped down two or more sodas a day experienced a 500% greater increase. The way artificial sweeteners confuse the body may play a part, but another reason might be psychological, says Minnesota-based dietitian Cassie Bjork. When you know you're not consuming any liquid calories, it might be easier to justify that double cheeseburger or extra slice of pizza.

3) It's associated with an increased risk of type 2 diabetes

Drinking one diet soda a day was associated with a 36% increased risk of metabolic syndrome and diabetes in a University of Minnesota study. Metabolic syndrome describes a cluster of conditions (including high blood pressure, elevated glucose levels, raised cholesterol, and large waist circumference) that put people at high risk for heart disease, stroke, and diabetes, Bjork explains.

4) It confuses your body

Artificial sweeteners have more intense flavor than real sugar, so over time products like diet soda dull our senses to naturally sweet foods like fruit, says Brooke Alpert, RD, author of The Sugar Detox. Even more troubling, these sugar stand-ins have been shown to have the same effect on your body as sugar. "Artificial sweeteners trigger insulin, which sends your body into fat storage mode and leads to weight gain," Alpert says.

5) It'll ruin your smile over time

Excessive soda drinking could leave you looking like a Breaking Bad extra, according to a case study published in the journal General Dentistry. The research compared the mouths of a cocaine-user, a methamphetamine-user, and a habitual diet-soda drinker, and found the same level of tooth erosion in each of them. The culprit here is citric acid, which weakens and destroys tooth enamel over time.

6) It has no nutritional value

When you drink diet soda, you're not taking in any calories—but you're also not swallowing anything that does your body any good, either. The best no-calorie beverage? Plain old water, says Bjork. "Water is essential for many of our bodily processes, so replacing it with diet soda is a negative thing," she says. If it's the fizziness you crave, try sparkling water.

7) Its sweetener is linked to headaches

Early studies on aspartame and anecdotal evidence suggests that this artificial sweetener may trigger headaches in some people. "I have several clients who used to suffer from migraines and pinpointed their 

cause to diet soda," Bjork says.