As it turns out, the brain is, well, smarter than we think it is. A new study has found that artificial sweeteners do not trigger the brain’s reward centre in the same way that regular sugar does, suggesting that if we’re left unsatisfied, we may be tempted to turn to the real thing later on.
The study identified a signal in the brain that distinguishes between energy-supplying sugars and their zero-kilojoule alternatives. When sugars are consumed, the brain registers the fuel and releases dopamine, a chemical that indicates reward. But in the absence of usable energy – that is, if there are no kilojoules that can be broken down – dopamine isn’t released, according to the study.
Although the research was conducted on mice using behavioural testing involving sugar and sugar substitutes while simultaneously measuring brain circuits for reward, the researchers believe the findings apply to people.
“According to the data, when we apply substances that interfere with a critical step of the ‘sugar-to-energy pathway’, the interest of the animals in consuming artificial sweetener decreases significantly, along with important reductions in brain dopamine levels,” says lead study author, Ivan de Araujo, Ph.D., associate professor of psychiatry, Yale University School of Medicine, US, who published the findings in the Journal of Physiology.
“It implies that humans frequently ingesting low-kilojoule sweet products in a state of hunger or exhaustion may be more likely to ‘relapse’ and choose high-kilojoule alternatives in the future.”
One takeaway could be that if your goal is weight loss, you might be better off having the fresh-baked cookie rather than the low-kilojoule alternative in the first place.
But Araujo sees a “happy medium”: producing products that combine sweeteners with minimal amounts of sugar so that energy metabolism doesn’t drop, while kilojoule intake is kept to a minimum.