A long-term high-fat diet causes brain shrinkage and waistline expansion.

According to recent research, eating fatty meals may not only increase your waistline but also damage your cognitive function.

A clear relationship has been shown between mice given a high-fat diet for 30 weeks, causing diabetes, and a subsequent decline in their cognitive abilities, including the onset of anxiety, depression, and worsening Alzheimer’s disease. The international study was conducted by neuroscientists Professor Xin-Fu Zhou and Associate Professor Larisa Bobrovskaya of the University of South Australia.

Due to poor metabolism brought on by brain alterations, mice with reduced cognitive function were also more prone to put on excessive weight.

Researchers from Australia and China recently reported their results in the journal Metabolic Brain Disease.

Associate Professor Larisa Bobrovskaya, a neurologist and biochemist at the University of South Australia, says the study adds to the increasing body of data connecting diabetes and obesity with Alzheimer’s disease, which is expected to affect 100 million people worldwide by 2050.

“Obesity and diabetes impair the central nervous system, exacerbating psychiatric disorders and cognitive decline. We demonstrated this in our study with mice,” Assoc Prof Bobrovskaya says.

In the study, mice were randomly allocated to a standard diet or a high-fat diet for 30 weeks, starting at eight weeks of age. Food intake, body weight, and glucose levels were monitored at different intervals, along with glucose and insulin tolerance tests and cognitive dysfunction.

The mice on the high-fat diet gained a lot of weight, developed insulin resistance, and started behaving abnormally compared to those fed a standard diet.

Genetically modified Alzheimer’s disease mice showed a significant deterioration of cognition and pathological changes in the brain while fed the high-fat diet.

“Obese individuals have about a 55% increased risk of developing depression, and diabetes will double that risk,” Associate Prof Bobrovskaya says.

“Our findings underline the importance of addressing the global obesity epidemic. A combination of obesity, age, and diabetes is very likely to lead to a decline in cognitive abilities, Alzheimer’s disease, and other mental health disorders.”

Reference: “Long term high fat diet induces metabolic disorders and aggravates behavioral disorders and cognitive deficits in MAPT P301L transgenic mice” by Jing Xiong, Isaac Deng, Sally Kelliny, Liying Lin, Larisa Bobrovskaya and Xin-Fu Zhou, 15 June 2022, Metabolic Brain Disease.
DOI: 10.1007/s11011-022-01029

The study was funded by the National Health and Medical Research Council.