A typical Western diet may affect your memory, research suggests.
Scientists from Macquarie University in Sydney gave 55 20-something volunteers high-fat, high-sugar meals for one week.
After indulging in the tempting treats – which included Belgian waffles and Coco Pops – the participants performed significantly worse on memory tests than the 55 “controls” who ate normally.
The Western diet is thought to disrupt the hippocampus region of the brain, which is involved in storing memories.
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Perhaps unsurprisingly, the junk food also encouraged the volunteers to overeat.
As well as processing and retrieving memories, the hippocampus is also thought to mediate appetite.
“After a week on a Western-style diet, palatable food such as snacks and chocolate become more desirable when you are full,” study author Professor Richard Stevenson told The Guardian.
“This will make it harder to resist, leading you to eat more, which in turn generates more damage to the hippocampus and a vicious cycle of overeating.”
When functioning optimally, the hippocampus may “block” tempting memories of food after we have eaten, putting us off any more food.
If this is impaired, we could get a “flood of memories”, making chocolate cake appealing even if we have “no space left”.
The scientists put these theories to the test by assessing the volunteers’ “word memory” before and after they ate Western style foods or as normal.
The participants also rated how appealing the food was.
“The more desirable people find the palatable food when full, following the Western-style diet, the more impaired they were on the test of hippocampal function,” said Professor Stevenson.
The scientists called the results, published in the journal Royal Society Open Science, “worrying”.
Fatty, sugary foods have been linked to obesity, heart disease and types 2 diabetes if consumed regularly, with the Macquarie research highlighting the diet’s more immediate effects.
Professor Rachel Batterham, from University College London, said the impact of Western eating habits on the brain is a “matter of urgency given the current food climate”.
In England alone, 29% of adults were classified as obese in 2017 – an 11% increase on the year before.
The US is also suffering, with obesity affecting 39.8% of adults in 2015/16.
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Professor Batterham added, however, that “further research with the application of more sophisticated neuroimaging methods” is required.
The Macquarie scientists hope processed foods will one day be regulated in the same way as cigarettes.
Tobacco products cannot be advertised in the UK and are sold in plain packaging with graphic warnings.
In an attempt to tackle obesity, the government introduced the Soft Drinks Industry Levy in April 2018.
The “standard rate” of 18p ($0.24) per litre applies to drinks with a sugar content of between 5g and 7.9g per 100ml.
“Higher rates” lead to charges of 24p ($0.31) per litre for drinks with 8g or more sugar per 100ml.
Scientists from the University of Oxford found this has reduced the amount of sugar in soft drinks sold in the UK by nearly a third.