Common Sugar Substitute May Trick Your Brain Into Eating More

A University of Southern California study finds that sucralose may increase hunger and alter brain activity, particularly in individuals with obesity.

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The popular sugar substitute sucralose—used by nearly 40 percent of Americans seeking to cut calories—may alter brain activity in ways that boost appetite, with particularly pronounced effects in people living with obesity, according to a new research.

Sucralose Could Trigger Hunger Signals in Brain

The study, conducted by the Keck School of Medicine at the University of Southern California and recently published in Nature Metabolism, indicates that consuming sucralose, a key ingredient in the popular sugar substitute Splenda, increases activity in the hypothalamus—a part of the brain that regulates appetite and body weight.

The researchers found that drinking sucralose increased feelings of hunger and brain activity in the hypothalamus, especially among those with obesity. Unlike sugar, sucralose did not increase hormones that triggered a sense of fullness.

“The body uses these hormones to tell the brain you’ve consumed calories, in order to decrease hunger,” study lead author Dr. Kathleen Alanna Page, director of the USC Diabetes and Obesity Research Institute, said in a statement. “Sucralose did not have that effect—and the differences in hormone responses to sucralose compared to sugar were even more pronounced in participants with obesity.”

“About 40 percent of Americans regularly consume sugar substitutes, usually as a way to reduce calories or sugar intake,” Page said. “But are these substances actually helpful for regulating body weight? What happens in the body and brain when we consume them, and do the effects differ from one person to the next?”

To investigate, the researchers conducted a randomized experiment with 75 participants, who were tested on three different occasions after drinking water, a beverage sweetened with sucralose, or a drink sweetened with regular sugar. Using magnetic resonance imaging, researchers recorded brain scans and collected blood samples and hunger ratings before and after drink consumption.

The researchers also found that sucralose changes the way the hypothalamus interacts with other brain regions involved in motivation. The findings also revealed that female participants experienced greater changes in brain activity compared with male participants, suggesting that sucralose could affect the sexes differently.

Sucralose may confuse the brain by providing a sweet taste without the expected caloric energy. “If your body is expecting a calorie because of the sweetness, but doesn’t get the calorie it’s expecting, that could change the way the brain is primed to crave those substances over time,” Page stated.

Artificial Sweeteners Carry Potential Risks

Sucralose can be up to 600 times sweeter than natural sugar, raising the taste threshold for sweetness. It carries no calories and will thus not induce fullness, “causing rebound overeating from the shortfall,” Nicolette M. Pace, a registered dietitian and nutritionist and founder of NutriSource Inc., told The Epoch Times.

She said that basic, unadulterated foods “are the way to go.”

While artificial sweeteners such as sucralose are approved for use, some studies suggest potential negative health effects, including alterations to the gut microbiome. Sweeteners such as xylitol and aspartame have been linked to cardiovascular risks.

Shelley Balls, another registered dietitian, expressed concern about sucralose consumption among children and adolescents. “It’s hard enough in today’s world to make healthy choices, but increasing cravings and hunger makes things even harder, which could potentially lead to obesity and increased chronic disease risk,” Balls said.

“Sucralose has also been shown to alter the gut microbiome, and as we know gut health is a key determinant of health that we always want to keep in mind.”

The researchers are already planning a follow-up study to explore how calorie-free sweeteners affect the brains of children and adolescents—who consume more sugar and substitutes than any other age group. “Are these substances leading to changes in the developing brains of children who are at risk for obesity?” Page said. “The brain is vulnerable during this time, so it could be a critical opportunity to intervene.”

Alternatives and Expert Recommendations

Starting healthy eating behaviors earlier in life is better when it comes to promoting overall health and decreasing the risk for chronic diseases, according to Balls.

“As a dietitian, I always recommend water as the main source of fulfilling hydration needs for optimal health,” she said. “I personally stay away from all artificial sweeteners.”

Normal sugar and honey—in moderation—are a healthier option, she added.

While all sweeteners should be consumed in moderation, natural sweeteners such as honey and sugar, unlike artificial sweeteners, offer potential benefits such as antioxidants and vitamins and are less likely to disrupt the gut microbiome.

However, for those looking for an alternative sweetener, she recommends trying monk fruit as it is a natural sweetener. “It’s 100 to 300 times sweeter than sugar so you may find you can use less of it.”

While monk fruit provides a zero-calorie, sugar-free alternative that could be beneficial for people managing diabetes, Balls advised consumers to read labels carefully. Many monk fruit products aren’t pure, often containing other artificial sweeteners or sugar alcohols.

“So purchase straight monk fruit sugar if you can.”