According to a recent study performed on rats, published in the journal Psycopharmacology, sudden drops in glucose can have a dramatic impact on our mood.

The study was conducted by the University of Guelph.  "We found evidence that a change in glucose level can have a lasting effect on mood," said Prof. Francesco Leri, Department of Psychology. "I was skeptical when people would tell me that they get grouchy if they don't eat, but now I believe it. Hypoglycemia is a strong physiological and psychological stressor."

"When people think about negative mood states and stress, they think about the psychological factors, not necessarily the metabolic factors," said PhD student Thomas Horman, who led the study. "But we found poor eating behaviour can have an impact."

In the experiment, conducted at Guelph, rats were injected with a glucose metabolism blocker, causing them experience hypoglycemia.  Rats were then documented experiencing avoidance behavior to the chamber where they experienced hypoglycemia.

This finding supports the idea that the animals experienced stress and depressed mood when they were hypoglycemic, he said.

For people who experience anxiety or depression, the study results have implications for treatment, said Horman.

"The factors that lead someone to develop depression and anxiety can be different from one person to the next. Knowing that nutrition is a factor, we can include eating habits into possible treatment."