A misperception I encounter frequently is that diet soda (or perhaps more specifically artificial sweetener) causes cancer. This is completely untrue. Splenda (sucralose) is safe. Equal & NutraSweet (both made from aspartame) are safe. Sweet ‘N Low (saccharin) is safe.
To be fair, back in the 1970’s, high doses of saccharin given to lab rats seemed to show an association with the rats getting bladder cancer. Of note, we’re talking massive doses. More importantly, the biological mechanism only applies to rats. It does not apply to humans. Regardless, after its approval, the FDA required saccharin to carry a warning mentioning this. Since that time, there has been no evidence that saccharin (or any other sweetener) causes cancer. In 2000, the FDA removed the warning language.
To repeat, artificial sweeteners are completely safe. They do not cause cancer. Indeed, they do not cause any health risks.
Should you choose artificial sweeteners over sugar? The choice is completely dependent on your desire to control calorie intake and on taste preference.
I remember when I was still practicing medicine . . . one of the drug reps brought in boxes of doughnuts (that was widely prevalent ten years ago and has all since disappeared). Anyway, on this particular day, one of doughnut options was “low-calorie” (“half the sugar, half the fat, same great taste”). I tried one. Let me tell ya . . . there was not the same great taste. Kudos to doughnut maker for marketing efforts, I suppose. If there really had been the same great taste, who would ever say “Sure they taste the same, but I want the two extra tablespoons of lard.”?
The taste of artificial sweeteners vs sugar is a different hurdle than trying to make good-tasting low-fat products. Artificial sweeteners taste different, but still sweet. If you can develop a taste for artificial sweeteners, I say ‘go for it.’ Americans get enough calories. As of yet, there’s no such thing as low-fat french fries. Might as well drink diet soda (if your palate accepts it) and avoid consuming those few extra calories. The same applies to kids, by the way. Safe is safe. If they’re going to drink soft drinks, no reason to fill them with sugar at the same time (just my humble opinion here). Make your own decision; hopefully this provides some information to help.