The claim: Diet soda helps you lose weight.

Diet soda typically contains sweeteners like Aspartame, Sucralose, or Ace-K, which are calorie-free. So drinking diet soda would seem to be an obvious way to help control your weight. But surprisingly, when you look at the science, that promise loses much of its fizz.

While some research has found that consuming diet soda and artificially sweetened foods leads to small reductions in weight and body fat, other studies have found no effects. And still others have linked diet drinks to weight gain.

There are several theories as to why diet drinks may not help and could possibly hurt when it comes to weight control.

Drinking diet soda may make us feel more virtuous and therefore entitled to eat those large fries or extra slices of pizza.

Also, artificial sweeteners may mess with our brains, causing us to crave sweets and other high-calorie foods.

Or it’s possible they may affect the gut by changing the balance of bacteria there, which have been tied to weight.

At this point, though, the evidence for all these ideas is limited.

There’s similar uncertainty when it comes to the safety of diet drinks.

In rats and mice, artificial sweeteners have been found to cause cancer. But rodents aren’t people so these findings may not apply to us.

Human research has linked diet drinks to diabetes, dementia, strokes, and other health problems. But these studies don’t prove cause and effect.

It’s possible that diet soda drinkers tend to have other traits that increase their risk of these conditions.

What we do know is that too much sugar can lead to obesity and diabetes, among other things, so regular soda, which is loaded with sugar, isn’t really a better option.

Your best bet is to limit intake of all soda, whether diet or regular, and instead stick with water. For sweetness, add some fruit. If you want bubbles, go for sparkling water. Whatever it takes to make it pop.

For more on weight loss, check out my book Supersized Lies, which reveals why standard advice often fails and what actually works to keep weight off.

Helping you be a healthy skeptic, I’m Robert Davis.