If you are obese, you are not only at risk of physical and psychological health problems such as diabetes, heart disease, depression and anxiety, but your high body mass index (BMI) is also likely to affect your episodic memory — the ability to recall past events, warns a new study.
A higher BMI was previously found to affect the structural and functional changes in the brain. But, it may also be accompanied by a reduced ability to form and/or retrieve episodic memories and affect the brain’s ability to perform certain cognitive tasks optimally, suggested the researchers.
The results showed that obesity might also impair an individual’s ability to use memory to help regulate consumption. In other words, it is possible that becoming overweight may make it harder for an individual to keep track of what and how much he or she has eaten, potentially making one more likely to overeat. “The possibility that there may be episodic memory deficits in overweight individuals is of concern, especially given the growing evidence that episodic memory may have a considerable influence on feeding behaviour and appetite regulation,” said Lucy Cheke, lecturer at the University.
However, she cautioned that not all overweight people are necessarily forgetful.
But if the results are generalised to memory in everyday life, then it could be that overweight people are less able to vividly relive details of past events — such as their past meals, the researchers explained in the study published in The Quarterly Journal of Experimental Psychology.
Obesity has been previously linked with dysfunction of the hippocampus — an area of the brain involved in memory and learning — and of the frontal lobe — the part of the brain involved in decision-making, problem solving and emotions.
Around 60 per cent of adults in Britain are overweight or obese, a number predicted to rise to approximately 70 per cent by 2034, the researchers noted. “Understanding what drives our consumption and how we instinctively regulate our eating behaviour is becoming more and more important given the rise of obesity in society,” Cheke added.
The researchers tested 50 participants aged 18-35 — with body mass indexes (BMIs) ranging from 18 through to 51. A BMI of 18-25 is considered healthy, 25-30 overweight, and over 30 obese. The participants took part in a memory test known as the ‘Treasure-Hunt Task’, where they were asked to hide items around complex scenes — for example, a desert with palm trees — across two ‘days’. They were then asked to remember which items they had hidden, where they had hidden them and when they were hidden.
Overall, the team found an association between higher BMI and poor performance on the tasks.