Obesity is a growing public health problem in the United States, particularly in middle-aged and older adults. One-third of the American adults are obese and another one-third is overweight

Moreover, this epidemic is not just restricted to the United States but is widespread worldwide affecting most countries.

Obesity has many complications, which adversely affect the health of the obese person.

Obesity impact on brain health

Declining cognitive function is one of obesity’s complications, which impairs the person’s memory, thinking skills, and learning.

Research confirms now that there is a definite association between obesity, memory loss, and dementia. Higher the BMI worse is the memory deficit.

There is growing evidence that suggests obesity is associated with brain shrinkage and development of neurodegenerative conditions such as Alzheimer ’s disease.

Areas of the brain mainly affected are those that control memory and imagination.

The hippocampus is a small area situated in the brain’s medial temporal lobe controlling learning and memory, particularly long-term memory.

It is found to be considerably smaller in obese individuals as compared to individuals with a healthy weight.

Effect of obesity on gray matter

A number of studies have shown that obesity is linked to a reduced volume of gray matter in people with both healthy and impaired cognitive function.

In addition, compared to healthy-weight people, obese people with higher BMI showed a reduced volume of gray matter in several cortical and subcortical areas of the brain such as the hippocampus, the prefrontal cortex, and other subcortical regions.

These findings were seen even after keeping any co-morbid conditions such as diabetes and hypertension under control. This strongly suggests a distinctive link between body fat and brain atrophy.

Effect on white matter

As regards the effect of obesity on the white matter of the brain, conflicting opinions exist.

Research on the effect of obesity on the white matter is conducted by doing an MRI to measure the volume of the white matter and by testing the thinking skills of the subjects.

While many studies suggest that obesity is associated with reduced volume of the white matter in several cortical and subcortical areas of the brain, other studies fail to establish this relationship.

But, the fact that how obesity speeds up the decline in the white matter still lies unexplained.

Researchers speculate that the probable cause could be the inflammation that accompanies obesity. Another probable cause could be the hormones that are produced by fat tissue.

How obesity affects cognitive function

Compared to their healthy counterparts, obese people usually compare poorly in the performance of cognitive tasks

What are the cognitive tasks?

In brief, the cognitive activity involves taking decisions, solving problems, memory, and judgment.

The cognitive functioning in obese people is mainly impaired in executive functioning and memory.

Further, studies indicate that obesity during middle age considerably increased the risk of developing dementia as compared to being of normal weight in midlife.

Various studies concluded are remarkably consistent with this finding.

Evidence suggests that more the period you have been obese, greater is the cumulative risk of developing cognitive deficiency in adults.

However, even being underweight is a risk factor towards developing dementia in late life.