According to the researchers, who published their study Wednesday in the Royal Society Open Science journal, eating such a diet can also make it difficult to control your appetite.
The study consisted of 110 lean and healthy adults between the ages of 20 and 23 who typically consume a healthy diet. Half of the participants were asked to consume their normal diets for a week, while the others ate a “western-style diet” consisting of fast food and waffles. One week later, the researchers found that those on the “western-style” diet did more poorly on memory tests than those who ate a normal, healthy diet. In addition, the “western-style” group had “measurable weakening of appetitive control,” according to the study.
“Demonstrating that processed foods can lead to subtle cognitive impairments that affect appetite and serve to promote overeating in otherwise healthy young people should be a worrying finding for everyone,” Richard Stevenson, a professor of psychology at Macquarie University in Sydney and one of the study’s authors, told the Guardian.
“This will make it harder to resist, leading you to eat more, which in turn generates more damage to the hippocampus,” he added, referring to the part of the brain associated with memory.
According to Stevenson, governments may eventually be pressured to impose restrictions on processed food.
“The new thinking here is the realization that a western-style diet may be generating initial and fairly subtle cognitive impairments, that undermine the control of appetite,” Stevenson told the Guardian, also noting that such diets have been linked to obesity, diabetes and dementia.
In a statement, Rachel Batterham, professor of obesity, diabetes and endocrinology at University College London, who was not involved in the study, applauded the study’s important findings but noted that further research is necessary to understand the links between the hippocampus and diet.
“Understanding the impact of a western diet on brain function is a matter of urgency given the current food climate. This research has provided data to support detrimental effects on both memory and appetite control after just one week of an energy-dense diet and may suggest a link between poor diet and impairment of the hippocampus, a key memory and appetite-associated brain region. The mechanisms at work remain to be elucidated and will require further research with the application of more sophisticated neuroimaging methods,” she told the Guardian.