It is common knowledge that consuming a large quantity of sugar can give you a physical and psychological high. A recent analysis concludes that, in fact, the reverse might be true. It will have escaped nobody's attention that sugar consumption across the United States has skyrocketed. In particular, sugar-sweetened soft drinks have taken off. From the late 1970s to the early 2000s, energy intake from sugary drinks increased by 135 percent.
A study using data that researchers collected during 1988-1994 and 1999-2000 found that the number one contributor of energy intake for both periods was soft drinks. Although the causes of obesity are complex, it is not a stretch to imagine that sugar-sweetened beverages play a significant role. Adverts for sugar-sweetened drinks often infer that they will boost mood and combat fatigue. This claim is likely to influence buyers, so understanding how accurate these claims are is important.
Recently, a number of researchers have looked, in more detail, at the relationship between sugar and mental health. One study, as an example, concludes that sugar intake seems to harm long-term psychological health. These types of investigation have reignited public interest in the cognitive effects of sugar intake. However, the results of the research to date are far from conclusive.
A group of researchers recently carried out a meta-analysis with the aim of understanding how acute sugar intake affects mood. The authors explain why they decided to investigate: "Interestingly, despite researchers not having reached a consensus regarding the exact effects of sugar on mood, it seems that the public strongly believes in the idea that sugar improves mood [...] and increases activity levels-especially in children."
For their analysis, the researchers used data from 31 existing trials. All of these studies met specific criteria. For instance, all of them were randomized control trials that involved healthy adults. They had also all investigated the effects of acute oral administration of carbohydrates as opposed to the long-term effects. The researchers looked at differences in a range of psychological parameters, including alertness, depression, calmness, fatigue, confusion, tension, and anger. They also looked at the effect of sugar intake after different lengths of time, running separate analyses for the effects at 0-30 minutes, 31-60 minutes, and more than 60 minutes. Contrary to popular belief, the meta-analysis found no evidence of any changes in mood at any of the time points following carbohydrate ingestion. The authors explain: "In fact, [sugar] consumption was related to decreased alertness and higher levels of fatigue within the first hour post-ingestion."
One of the authors, Prof. Elizabeth Maylor from the University of Warwick, says, "We hope that our findings will go a long way to dispel the myth of the 'sugar rush' and inform public health policies to decrease sugar consumption."
