Apparently, America's love affair with diet soft drinks seems to be dialing down.  

According to the Wall Street Journal, sales of diet soda have declined nearly seven percent in the past year. Sales of regular of soda have dropped a little more than two percent over a year's time, based on findings from Wells Fargo research.

"We used to say, 'I'm drinking diet. It's fine.' But these days it's becoming a little bit of a guilty confession in my office," said nutritionist Rachel Bell, author of "Eat to Lose, Eat to Win".

Diet soda has been the topic of many studies over the recent years. Some show the link between the amount of diet soda consumed and an individual's weight gain. Researchers at the University of Texas Health Science Center in San Antonio linked obesity and diet, suggesting that those who drank soda "saw their waist lines grow five times faster than those who did not drink diet soda."

Other studies have linked diet soda to health conditions such as strokes and Type 2 diabetes. A study by Purdue University showed artificial sweeteners can sometimes have a negative effect on an individual's metabolism and that diet brands disrupt how the body processes regular sugars.

In August, Coca Cola Co., launched an advertising campaign to drive off customers' fears about their products after studies suggested that aspartame, a sugar substitute used in their drinks, might be dangerous. The study stated the artificial sweetener was linked it to potential health risks, such as cancer and premature birth. The studies have been blamed for the a drop in sales of diet soda.

The European Food Safety Authority said Tuesday, that aspartame is safe for humans to consume, but only at the levels currently used in diet soft drinks.

"Our industry believes in the soft-drink business and sees opportunity for continued innovation and growth," the American Beverage Association said.

According to ABC News, energy drinks and water have seen the biggest growth in the beverage industry. However, some experts believe that not enough specifics is known about the effects of diet soda on someone's health, which is the beverage's biggest issue.  

"We don't really know a whole lot about what these specific artificial sweeteners do to the brain reward system," Nicole Avena, Ph.D., a sugar addiction researcher and assistant professor at the University of Florida, told the Huffington Post. "We know their safety, they're FDA-approved - but don't know enough about the long-term effects on appetite."