In a study using human volunteers that was published by the Sydney researchers two years ago, people fed junk food for five days showed slower reaction times. Picture: Nosipho Malotana

Sydney - Putting rats on what Australian researchers called a cafeteria-style diet for less than a week caused irretrievable memory loss.

“We were surprised at how fast it was,” University of New South Wales pharmacologist Margaret Morris said on Tuesday.

“Within six days of the diet the animals performed less well on a spatial memory task.” Morris told national broadcaster ABC that sugar alone rather than the sugar-fat combination typical in poor diets might be the culprit. She said memory impairment was not reversed when the rodents were switched back to a healthy diet.

Rats fed fat, cakes, biscuits and a 10 percent sugar solution consumed five times more energy than those in the control group. They performed worse in memory tests than those on a healthy diet.

The memory loss was evident even before the rats put on weight. “We suspect these findings may be relevant to people,” Morris said.

In a study using human volunteers that was published by the Sydney researchers two years ago, people fed junk food for five days showed slower reaction times after five days than those in the control group.

The latest study, published in the journal Brain, Behaviour and Immunity, concluded that “relatively short exposures to diets rich in both fat and sugar, or rich in sugar, impair hippocampal-dependent place recognition memory prior to the emergence of weight differences.” - Sapa-dpa