( CNN ) -- For some time , sugary soft drinks have been under attack as a major contributor to the obesity epidemic plaguing the nation , if not the world . As a result , sales of regular soft drinks have been dropping . Apparently , sales of diet soft drinks have taken even more of a hit . So it comes as no surprise that Coca-Cola is planning to launch a new ad campaign defending -- and promoting -- its diet soft drinks . The ads are going to focus on the safety of artificial sweeteners , or aspartame , in diet soda . Coca-Cola must believe that some of the fall in sales is due to concerns over the health effects of artificial sweeteners . Here 's the thing : There 's a lot of science out there , and it 's hard to say that aspartame holds much of a health risk . Aspartame was first approved for use in 1981 , but it was n't until 15 years later that health concerns showed up . In 1996 , a research paper showed that there had been a recent increase in brain tumors and hypothesized that this might be due to aspartame . Mind you , it did n't prove that was so . But the potential link was all the media needed to go crazy . TV shows , magazine articles , and newspapers all questioned whether the artificial sweetener was safe . Further work using data from the National Cancer Institute showed that the increase in brain tumors really began in 1973 , long before aspartame was introduced . Moreover , the increases in incidence of cancer were seen primarily in the elderly , which as a group , was not the major consumer of diet soda . And there 's more . A randomized , double-blind , placebo controlled trial showed that aspartame did n't affect memory , behavior or mood . And a study published in 2006 followed more than 285,000 men and almost 190,000 women and could n't detect any relationship between aspartame and brain or blood cancer . Some research has shown that drinking artificially sweetened beverages does n't promote weight loss , or even promotes weight gain . More often than not , this is because people wind up overcompensating for the calorie savings they think they 're getting by switching beverages ( think of the person who orders dessert as a reward for having diet soda ) . But in those cases it 's not the diet beverage that caused weight gain ; it 's dieters ' behavior . You can even find people who postulate that artificially sweetened beverages trick the brain into wanting more calories . There 's really no proof of that . Finally , some will claim that diet drinks will cause the brain to release insulin , which can change your metabolism and make you hungry . That 's a bit hard to swallow . That 's like saying if you ate sugar-dense food that tasted terrible , it would trick your brain into not releasing insulin . It 's the pancreas that releases insulin anyway , not the brain . The bottom line is that artificially sweetened beverages are safe . That does n't mean you should drink tons of them . My wife and I limit our kids ' consumption of soda to caffeine-free , diet types . But we do n't let our children drink them every day . We stress moderation in everything . The fact that Coca-Cola and other companies are seeing sales drop across the board is likely to create a backlash against artificial beverages in general . It 's hard to get too upset about that , since our consumption of them was likely too high to begin with . But we should n't make the perfect the enemy of the good . Given a choice between a sugared soda and a sugar-free soda , I 'd rather see my kids choose the latter every time . There 's an abundance of evidence that the sugar is contributing to health problems ; there 's not much conclusive evidence that artificial sweeteners in diet sodas are doing the same . The opinions expressed in this commentary are solely those of Aaron Carroll .
Coco-Cola is launching a new ad campaign to defend artificial sweeteners in diet soda . Aaron Carroll : It 's no surprise , since sales of diet soda is dropping more than regular soda . He says there 's little evidence to support the idea that artificial sweeteners pose health risk . Carroll : Given a choice , it 's still better to choose sugar-free soda over sugared soda .