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Turns Out, Diet Soda May Actually Make You Gain Weight

A new neuropsychology study found artificially sweetened drinks may trigger unexpected cravings in the brain.

If you're one of the 40% of people who've been substituting sweeteners for sugar—specifically, drinking diet soda instead of regular—new brain science reveals this could be producing the exact opposite effect from what you want. A riveting recent study has identified a link between diet soda and calorie intake… and the scientific explanation is likely to make you think.

Keep reading to learn about this study that focused on diet soda and weight gain, recently published in the journal of Nutrition, Obesity, and Exercise. (Sometimes it helps to remember you don't have to sacrifice wholesome, healthy foods in the quest to get trimmer—check out the 45+ Best Cozy Casserole Recipes for Weight Loss.)

The Neuropsychology of Soda Drinking


Led by a group of researchers studying neuroscience, obesity, and medicine at the University of Southern California, this study engaged 74 healthy participants between the ages of 18 and 35 years old. Participants' body mass index (BMI) was used to determine whether they were of normal weight, overweight, or obese.

The researchers report their objective was to "examine neural reactivity to different types of high-calorie food cues (i.e., sweet and savory), metabolic responses, and eating behavior" after some of the participants consumed sucralose (an artificial sweetener), while others consumed a sugary drink and another group drank only water.

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The Metrics

Doctor checking blood sugar level with glucometer. Treatment of diabetes concept.

Between March 2020 and March 2021, the participants reported three times for the research team to collect their data. The participants underwent magnetic resonance imaging (MRI) of the brain and had their blood taken at baseline after a 12-hour fast, as well as 10, 35, and 120 minutes after they received one of three beverages: A drink containing sugar (approximately six tablespoons diluted in 10 ounces of water that provided 300 calories), artificial sweetener (of an amount whose sweetness was equal to the sugar, also dropped into 10 ounces of water), or plain water.

Then, the researcher report they measured participants' levels of glucose, insulin, ghrelin (known as the hormone that stimulates hunger), and leptin (a hormone that regulates food intake and energy expenditure).

At that point, the researchers presented the participants with a buffet meal that they were invited to enjoy freely.

RELATED: Everyday Habits That Cause Obesity, Says Science

Fascinating Results

lunch and soda

Perhaps unsurprisingly, sugar drinks were associated with greater production of glucose (blood sugar), insulin, and hormone levels that indicated a more satiated appetite.

Interestingly, the results show that calorie consumption increased significantly among female participants, and those who were obese, when they'd been part of the diet drink-consuming group.

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What It Means

Diet soda
Courtesy of Shutterstock

The researchers state that females had "greater caloric intake after the sucralose vs sucrose condition"—meaning overall, the women who drank artificial sweetener ate more than those who'd consumed the sugary drink.

Some observers are concluding that may indicate artificial sweeteners stimulate the brain to crave more food than sugar drinks do. Indeed, this study's findings could suggest that if diet soda is a regular player in your diet, it's possible that's leading you to consume more calories than you would if you stuck with water… and perhaps more calories than you believe you're taking in.

But, one important note the researchers make is that "neither male participants nor female participants fully compensated for the sucrose drink condition caloric preload." This statement makes an important point: It seems the group who drank the sugar beverages still consumed the greatest calories overall.

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Krissy Gasbarre
Krissy is a senior news editor at Eat This, Not That!, managing morning and weekend news related to nutrition, wellness, restaurants and groceries (with a focus on beverages), and more. Read more about Krissy
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