Food and Behaviour Research

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No such thing as 'sugar rush' - sugar worsens mood rather than improving it

University of Warwick


Sugar does not improve mood and it can make people less alert and more tired after its consumption, according to a new study.


Although it's widely believed that sugary foods or drinks can boost mood and combat fatigue, the actual research evidence shows this simply isnt true.

Instead, consuming sugar has no effect on mood, and actually reduces alertness and increases fatigue, according to a systematic review of human randomised controlled trials (the highest level of scientific evidence for assessing causal effects).

For details of the underlying research, see:

Sugar does not improve mood and it can make people less alert and more tired after its consumption – according to a new study by the University of Warwick, Humboldt University of Berlin, and Lancaster University.

The research team set out to examine the myth of the 'sugar rush': can sugar really put you in a better mood?

Using data collected from 31 published studies involving almost 1300 adults, Dr. Konstantinos Mantantzis at Humboldt University of Berlin, Dr. Sandra Sünram-Lea at Lancaster University, and Dr. Friederike Schlaghecken and Professor Elizabeth Maylor in the University of Warwick's Department of Psychology investigated the effect of sugar on various aspects of mood, including anger, alertness, depression, and fatigue.

They also considered how factors such as the quantity and type of sugar consumed might affect mood, and whether engaging in demanding mental and physical activities made any difference.

The researchers found that :

  • sugar consumption has virtually no effect on mood, regardless of how much sugar is consumed or whether people engage in demanding activities after taking it
  • people who consumed sugar felt more tired and less alert than those who had not
  • the idea of a 'sugar rush' is a myth without any truth behind it

Professor Elizabeth Maylor, from the University of Warwick, commented: "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."

Dr. Konstantinos Mantantzis, from Humboldt University of Berlin, who led the study, said:

"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. Our findings very clearly indicate that such claims are not substantiated – if anything, sugar will probably make you feel worse."

Dr. Sandra Sünram-Lea added: "The rise in obesity, diabetes and metabolic syndrome in recent years highlights the need for evidence-based dietary strategies to promote healthy lifestyle across the lifespan. Our findings indicate that sugary drinks or snacks do not provide a quick 'fuel refill' to make us feel more alert."