A new study published in the journal Obesity revealed that older adults whose weight or body composition fluctuated the most experienced significantly faster cognitive decline compared to those with stable measures.
A research team from the Department of Nutritional Sciences at Pennsylvania State University found that adults over the age of 65 who are underweight or experience a weight fluctuation of over 5 per cent may face a faster rate of cognitive decline.
“We examined 11 years of data on weight, BMI, and waist circumference. Any way we looked at the data, the relationship was crystal clear — the more a person’s weight varied from year to year, the faster that person experienced cognitive decline,” said Muzi Na, associate professor of nutritional sciences and senior author of the study.
The team analysed cognitive performance data from 4,303 participants in the US National Health and Aging Study over an 11-year period, from 2011 to 2021. The study used a composite index, which included tests of memory, orientation, and executive function, to measure cognitive abilities. During the examination period, the scientists were tracking body mass index (BMI), body weights, and waist circumference, which were measured repeatedly, allowing for an accurate assessment of average changes and year-to-year variability.
According to the findings, maintaining a stable weight was linked to the slowest rate of cognitive decline, while those who experienced the most significant weight fluctuations had a decline rate two to four times faster.
The scientists also discovered even moderate losses of 5 per cent were linked to cognitive decline, highlighting weight loss in late life as a potential warning sign. What’s more, people who experience weight cycling, which is a repeated loss and regain of at least 5 per cent body weight, showed nearly double the cognitive decline compared to those with stable weight.
However, People who only gained weight experienced a similar rate of cognitive decline as those whose weight stayed the same. The researchers emphasised that this doesn’t mean gaining weight is helpful. “Mid-life obesity is a known risk factor for cognitive decline later in life, but there is an ‘obesity paradox,’ associating late-life obesity with a healthier cognitive trajectory,” Na added.
The research team suggested that regularly monitoring weights could be a helpful way to protect cognitive health. However, according to Na, self-monitoring is what matters the most. For the most accurate data, Na recommended weighing at the same time each morning, for example, after waking up but before breakfast and after a bathroom trip, while wearing the same clothes.
