No…. but it’s a little more complicated than that.
A study was done in November of 2015 detailing that diet soda can benefit people trying to lose weight, at first it seems like a really well-thought-out study, until you realize that Coca Cola paid the authors 1000 dollars each as a grant. But does this make the data obselete? Well, it makes it untrustworthy at best. But regardless of any of this, even if this study is wrong, the answer is still No.
Diet soda would be equivalent to that of Water, or sugarless Kool-aid mix. There are no calories or almost no calories in it, therefore it CAN’T increase your weight. It also CAN’T decrease it as well. In order to lose weight you need a caloric deficient, which is to eat less than you are burning.
And before anyone uses it, there was one analysis done in 2014 that tested the “Low Calorie Sweeteners Make You Hungry” hypothesis of diet sodas, and came back with no support for it:
“Conversely, a hypothesis that LCS intake promotes, rather than prevents, weight gain by altering taste and metabolic signaling, decreasing satiety, and increasing appetite, hunger, sweets cravings, and ultimately food intake emerged nearly 3 decades ago. However, a recent review of randomized controlled trials (RCTs), and new findings from an RCT that examined the effect of low-calorie sweetened beverages (LCSBs) on overall dietary patterns, failed to support this hypothesis.”
The science does not support than diet sodas do anything other than give you non-fluoridated flavored water to drink that isn’t good for your teeth. But in terms of weight loss or weight gain, diet sodas are practically useless. They are a much better alternative than sugar-filled soda, but it’d be good to have an alternative to them as well.
Don’t demonize diet sodas for pseudoscientific ideas of weight gain, but don’t make the false assumption that they will in any way help anyone lose weight.