They’re billed as an on-the-go meal and some even have claims like “proven to help reduce appetite!”
But many Americans say they are hungrier after they eat a protein bar.
There are Reddit forums and videos on social media about this problem, with users saying they felt “extra hungry” or ended up drinking 20 in one sitting.
Many gym enthusiasts and nutritionists will advise clients to eat protein bars because protein is more satiating than the other two macronutrients: fats and carbohydrates.
But registered dietitians believe the culprit is sucralose, a sweetener used in the most popular protein bars from Quest, Barebells and Fulfill.
Many fans of Quest bars and other protein bars say they have become hungrier than before, which dietitians attribute to sucralose.
Katie Lopez, a registered dietitian in New Hampshire, told DailyMail.com, “Personally, I don’t eat sucralose and minimize food additives and packaged and processed foods.
She added that it “causes binge eating.”
She recommended bars with at least 10 g of protein and whole food ingredients, such as Aloha and Rx bars, who do not use sucralose.
Consuming something that has been artificially sweetened can lead to cravings for more food, even if the sweetened product contains a high amount of protein.
The lack of calories in sucralose along with its extreme sweetness’further fuels the food-seeking behavior and lack of a sense of reward in the brain can make a person feel like they need to eat more.
It explains the dozens of fitness forums where people sought answers about their turbo-charged appetites after eating a Quest protein bar.
One Reddit user said, “After introducing and loving a Quest Bar a few weeks ago, I definitely feel like I’m having a harder time staying under my calorie limit because I’m hungrier throughout the day.”
Another said: ‘Quest bars make me hungry…I guess they raise my glucose levels. I get a headache if I eat one.”
Despite its popularity and promise to beat hunger on the go, protein bars containing sucralose may actually increase cravings for sweet foods.
Yale researchers said: ‘Repeated exposure trains taste preference. There is a strong correlation between a person’s usual intake of a flavor and the intensity of preference for that taste.’
Zero-calorie sweeteners are extremely popular because of their cost-effectiveness (a small amount surpasses real sugar in terms of sweetness) and their reported benefits over eating real sugars.
Sucralose, marketed as Splenda, is about 600 times sweeter than real sugar. Instead of satisfying people’s sweet tooth, research has shown that people want to eat more
Many popular protein bar brands, such as Quest, Barebells, and Fulfill, use sucralose in their bars
However, the evidence supporting health claims touting the benefits of artificial sweeteners is mixed. Several studies have shown that animals fed a diet high in sucralose eat more food later, despite consuming enough calories to feel full.
Matthew Kadey, a registered dietitian based in Ontario, said: ‘In women and obese people, drinking artificially sweetened beverages can cause the brain to become hungry; the brain can sense that the body did not get the sugar calories it expected from the sweet drink.
‘This in turn may lead people to consume more, not fewer, calories throughout the day.’
Sucralose, sold under the brand name Splenda, is about 600 times sweeter than table sugar without the calories. Sucralose has been used since 1999 and is a popular choice for people looking to reduce their sugar intake.
Sucralose can be found in everything from baked goods to drinks and chewing gum.
People intuitively turn to calorie-free sweeteners when trying to lose weight. But several large-scale studies have shown a positive relationship between eating artificial sweeteners and weight gain.
A growing number of studies show that artificial sweeteners such as sucralose do not activate the sweeteners food reward route in the brain because they do not provide calories the way sugar does.
Sucralose contains no calories. The lack of a match between calories and sweetness causes the body to eat more sweet foods
Eating artificial sweeteners is generally a safer bet for diabetics than real sugar, but studies on sucralose have shown that it can increase blood sugar levels, leading to a spike and subsequent crash.
Artificial sweeteners do not activate what scientists call the post-ingestion component: processes such as digestion, nutrient absorption and the release of fullness hormones.
Counterintuitively, eating too much artificial sweetener can lead to weight gain.
A 2021 report in JAMA network opened putting sucralose to the test. Researchers at the University of Southern California enrolled 74 control subjects who drank 300 milliliters of a drink sweetened with sucrose (table sugar), a drink sweetened with sucralose or water over three visits.
Two hours after drinking, researchers performed MRIs to look specifically at how parts of the subjects’ brains involved in appetite control responded to pictures of high-calorie foods like a hamburger and donuts.
They also measured blood sugar, insulin levels and other metabolic hormones in the blood. They then recorded the amount of food consumed at a snack buffet offered at the end of each session.
Scans showed increased activity in parts of the brain involved in appetite and cravings in both women and obese people who drank sucralose, compared to those who drank drinks sweetened with real sugar.
The women who drank sucralose-sweetened drinks also ate more at the buffet after each session.
And despite being sugar-free and billed as safe for people with diabetes, a study published in the journal Diabetes Care showed that sucralose dramatically increased blood sugar levels in obese people whose bodies were particularly sensitive to insulin changes.
Ms Lopez said: ‘You can measure the glucose response to consuming a protein bar via a (continuous glucose monitor) or a finger prick. If you create a rapid rise in a short period of time, followed by a rapid decline, it will contribute to hunger.”