Is ‘Sugar Rush’ All In Our Heads? New Study Raises Doubts About Sugar’s Effect on Mood

By | April 26, 2019

Though most people have probably reached for a candy bar or a pint of ice cream to boost their mood, or a can of soda for some energy, a new study suggests that this apparently natural inclination may be useless, or worse. The meta-analysis from University of Warwick and Humboldt University finds that people get neither a mood boost or an energy boost from sugar, and may even feel lower in the hours after consuming it.

The study was published this month in the journal Neuroscience & Biobehavioral Reviews. 

A slew of earlier studies had suggested that carbohydrate consumption is associated with a number of benefits including increased energy and reduced fatigue, enhanced cognition or clear-headedness, and improved mood. But the research on carbs and mood is actually not so reliable, the researchers behind the new study write, and some research even suggests it has negative effects.

So to tease it all apart and get to the heart of the connection, the team looked back over data from 31 published studies which included about 1,260 adults. They analyzed how the studies were executed, taking into account variables like how long participants fasted in the studies, what kind of sugar they were asked to consume (glucose, sucrose, or carbohydrates from energy drink, etc), and the “dose.” And they looked at various cognitive and mood constructs, like alertness, calmness, connectedness, anger, confusion, depression, fatigue, tension, and vigor. They also looked at three time periods after sugar consumption: immediate (0–30 min), short-term (31–60 min), and long-term (61+ min).

The short version of the results is that the team didn’t find any positive effects of carbs in any of the timeframes they analyzed, and in fact, they found some negative ones. “Overall, our meta-analysis provides no evidence of mood facilitation following CHO [carbohydrate] ingestion at any time-point following consumption,” the authors write. “In fact, CHO consumption was related to decreased alertness and higher levels of fatigue within the first hour post-ingestion.”

Since there was also no boost in mood after an hour post-sugar-consumption, the team points out that the serotonin hypothesis for carb consumption (i.e., that carbs boost serotonin levels, thereby boosting our moods) isn’t borne out by the study. None of the mood measures, including, they point out, depression, tension, and anger, showed any benefit after sugar consumption.

And for those who believe in a “rush” right after you eat sugar, the study again disappoints. Even in the earlier timeframe, there were only negative effects on mood and alertness. The authors write, “similar to the results obtained from the 61+ [minute] time window, CHOs did not seem to lead to improvements in any mood constructs (including overall mood) during the earlier time windows. In fact, the only significant effects identified in our meta-analysis speak against CHO-related facilitation and suggest that, compared with placebo, CHO leads to mood decrements. Specifically, CHO consumption was related to greater fatigue and less alertness, 0–30 min and 31–60 min post-ingestion, respectively.”

So this is not great news for people who like their afternoon sugar.

“The idea that sugar can improve mood has been widely influential in popular culture, so much so that people all over the world consume sugary drinks to become more alert or combat fatigue,” said study author Konstantinos Mantantzis in a statement. “Our findings very clearly indicate that such claims are not substantiated – if anything, sugar will probably make you feel worse.”

It’s worth pointing out that one limitation of the study is that the participants were all healthy people, and it’s possible that different results would be seen in those who are depressed or have other mental health issues (for instance, the authors point out that other researchers have “coined the term ‘carbohydrate-craving’ depression to describe a clinical population showing excessive CHO intake as a means of ‘self-medicating’ to improve mood”). Differences results may also be observed in people whose bodies process sugar more efficiently or poorly, and so on.

But the study does generally throw a kink in the idea of a sugar rush, suggesting that maybe it’s all our heads, and more a matter of psychology than physiology. So it may be smarter to go for a cup of coffee if you need a pick-me-up, since it’s repeatedly been shown to benefit both mood and long-term health. And maybe, if you need it, throw in a side of low-sugar dark chocolate—but an afternoon doughnut may just make you feel worse.

Forbes – Healthcare