A team of Australian researchers has found a link between junk food and memory loss.
The researchers from the University of New South Wales placed rats on a diet high in sugar and fat and compared their performance with rodents on a healthy diet.
Lead researcher Margaret Morris said the rats on the poor diet developed an impaired memory after just six days.
"Poor diet was associated with a cognitive decline that happened very quickly. So within six days of the diet, the animals performed less well on a spatial memory task. We were surprised at how fast it was," she said.
It was found that the animals being fed a poor diet also showed inflammation in the brain's hippocampus region, the part of the brain that is involved in memory forming and storing.
"It's a little bit to early for us to say that two are causally related, but we believe that the inflammatory change is probably highly relevant for the cognitive decline," she was quoted as saying by the ABC news.
"So we need to do more work. For instance, what if we prevent that inflammation? Could that preserve the brain function? Those are the sorts of questions we want to ask."
Morris said the memory issues became apparent well before the animals showed any physical symptoms.
The animals of course weren't obese after just six days on the diet. So the changes in cognition, the loss of memory, happened well before there was any weight change," she said.
She said it is hard to say what the implications of the trial could be for humans.
"It's hard of course to extrapolate to humans. But there is data in human volunteers fed a poor junk diet for just five days, that there was a loss of executive function," she said.
"So longer reaction times, for instance."