Diet Pepsi unveiling a new aspartame free formula

We told you a change was in the works, and now it is here. Diet Pepsi is unveiling its newest formula this week. The soda is now Aspartame free.

PepsiCo says the change comes in response to customer feedback; it's one of the top customer complaints.

On the outside, the changes in packaging are subtle. New cans say "Now Aspartame Free" above the circular Pepsi logo, and the ingredients list is different.

The question now: will consumers notice a difference with taste? A company representative says the taste profile is not identical, but should be familiar to Diet Pepsi's loyal fan base.   

This is the second revamp in recent years. In 2012, Diet Pepsi tried combining aspartame with acesulfame potassium, which has been dubbed "ace-K". This latest reformulation combines "ace-K" with sucralose -- the same sweetener in "Splenda."

Diet Coke, Diet Dr. Pepper and Fanta Zero are still made with Aspartame. The FDA approved aspartame, also sold as "Equal", and "NutraSweet", for use in soda in 1983, and in 1996 approved it as a "general purpose sweetener".

Some consumers don't like the taste of aspartame. Others expressed concerns about neurological health risks, like migraines and muscle spasms. When aspartame breaks down, it creates a small amount of methanol, or wood alcohol, which the body converts to formaldehyde, or embalming fluid. Experts argue that the amount of methanol is very small, and natural products, like citrus fruit, juice, tomatoes and tomato juice, also break down, in part, into methanol.   

More than 100 studies have found it is safe for most people to use. The FDA says people with a rare hereditary disease called PKU can't metabolize some of the chemicals used in aspartame production.