Childhood Obesity: Diet Soda & Weight Loss
Although it seems to go against common sense, drinking diet soda—even those with zero calories—doesn't contribute to weight loss. In fact, several scientific studies have shown that the more diet soda a person drinks, the greater the risk of becoming overweight. Scientists aren't entirely sure why diet sodas seem to promote weight gain, but it could be that the artificial sweeteners in diet drinks actually stimulate your appetite, which causes you to eat more than you normally would. When you take in more calories than your body needs, you end up gaining weight.
This doesn't necessarily mean that you're better off drinking regular soft drinks. A 12-ounce can of regular soda contains about 10 teaspoons of sugar, which is more than most people need in an entire day.
It's OK to treat yourself to a soda every now and then, but when you're thirsty, your best bet is to bypass the soft drinks and grab a glass of water instead.