Diet versions of fizzy drinks aren't necessarily better for your health - the science explained

Many people choose beverages with artificial sweeteners rather than the so-called 'full fat' sugary versions for health reasons. However, new research suggests that drinking a diet fizzy drink while eating carbohydrates might do you more harm than drinking a full sugar version.

The study found that, while artificial sweeteners used to replace sugar have no impact on their own, when consumed with a carbohydrate they decrease the brain’s response to sweet tastes.

This could lead to eating more food to try to satisfy those sugar cravings, which could, in turn, lead to weight gain.

Scientists examined how the brain responds to sweet tastes

Scientists at Yale University examined 45 volunteers of a healthy weight, who consumed seven beverages over a two week long period.

The investigators conducted studies before, during and after the testing period, including performing MRI scans to look at how the brain responds to sweet tastes. Some participants drank fruity soft drinks with added table sugar, while others had beverages with the carbohydrate maltodextrin.

The latter group showed more changes in the brain’s response to sweet taste, as well as the body’s insulin sensitivity and glucose metabolism.

Tricking the brain about the number of calories present?

"When we set out to do this study, the question that was driving us was whether or not repeated consumption of an artificial sweetener would lead to a degrading of the predictive ability of sweet taste," explained Professor Dana Small, director of the modern diet and physiology research centre at Yale University.

“This would be important because sweet-taste perception might lose the ability to regulate metabolic responses that prepare the body for metabolising glucose or carbohydrates in general.

“Perhaps the effect resulted from the gut generating inaccurate messages to send to the brain about the number of calories present. The gut would be sensitive to the sucralose and the maltodextrin and signal that twice as many calories are available than are actually present."

'Drinking diet sodas with carbohydrates is not advised'

The study, published in the journal Cell Metabolism, concluded that while it is okay to have diet fizzy drinks once in a while, drinking them with carbs is not advised.

"If you’re eating french fries, you’re better off drinking a regular Coke or – better yet – water. This has changed the way that I eat, and what I feed my son. I’ve told all my friends and my family about this interaction,” Professor Small concluded.

Reported in the Metro, the Calorie Control Council, which reviews low-calorie sweeteners and sugar replacements, responded to this study, commenting, "The Calorie Control Council is reviewing the small study’s findings and methodology but stands by the overall safety and benefits of sucralose and other commonly used low-and-no-calorie sweeteners which have been confirmed through decades of scientific research."