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Do 'Diet' Soft Drinks Promise Weight Loss?

By Richard Dahl on January 03, 2020

If you're a drinker of diet soda, you might assume it will help you lose weight.

On Dec. 30, however, a federal appeals court said your assumptions may be wrong.

The 9th U.S. Circuit Court of Appeals ruled 3-0 to dismiss a case that was filed in 2017 by a California woman who was upset that drinking Diet Dr. Pepper for 13 years did not result in significant weight loss.

The plaintiff, Shana Becerra, has struggled with obesity since childhood, and started drinking Diet Dr. Pepper on the assumption that it would help her lose weight.

After Becerra became suspicious that Diet Dr. Pepper wasn't doing its assumed job, she conducted her own investigation and learned that aspartame, the sweetener in diet Dr. Pepper, has been found in several studies to produce weight gain — not weight loss.

That does sound like an unsettling discovery, and in Becerra's case it was upsetting enough for her to file a lawsuit.

Does 'Diet' Promise Anything?

Becerra cited the aspartame studies in her complaint and claimed that the marketing of Diet Dr. Pepper made an "implicit promise" that because the beverage did not contain sugar or calories it would aid in weight loss or healthy weight management.

In other words, what does the word "diet" really mean on a diet-beverage can?

In 2018, however, U.S. District Court Judge William H. Orrick granted Dr. Pepper's motion to dismiss the case, saying that Becerra failed to make a strong enough case. She appealed, but on Dec. 30, the 9th Circuit upheld the lower court.

"No reasonable consumer would assume that Diet Dr. Pepper's use of the term 'diet' promises weight loss or management," Judge Jay S. Bysbee wrote.

Instead, he wrote, the term simply means fewer calories than sugared drinks.

So if you think you're going to lose weight by drinking "diet" soda, think again.

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