Despite the increased attention obesity is getting as both a national and global pandemic, rates continue to increase. It affects more than one third of the world's population.
Interestingly, midway into the year of 2020, many researchers were concerned that COVID-19 lockdowns and restrictions were going to fuel obesity due to emotional stress, physical inactivity, social distance, and economy-related anxiety.
Diseases of obesity are also on the rise. Some of the most widely known diseases of obesity are heart disease, cancer, and diabetes. Obesity research, however, is only beginning to reveal lesser-described consequences of obesity on other organ systems, such as conditions affecting respiratory, reproductive, immune, or cognitive function.
An "Obese" Brain
Let's just examine one of these - cognitive function.
A large 2020 brain imaging study in the Journal of Alzheimer's Disease analyzed brain scans from more than 17,000 people. Scientists examined brain activity and blood flow because low blood flow is one factor from brain scans that can be used to predict Alzheimer's risk.
They found that as body weight increased to the point of obesity or morbid obesity, blood flow in the brain decreased. This pattern was observed in all regions of the brain, including parts of the brain most prone to being affected by Alzheimer's, such as the hippocampus, the temporal, and the parietal lobes.
Interestingly, a 2015 study found that increased body fat was associated with decreased brain volume (specifically of gray matter).
This is just one example of how the effects of obesity do not necessarily stop at parts of the body where fat mass is accumulating. The effects can be far-reaching.
The Common Denominator
What is it about obesity that causes so much damage in the body's organ systems?
Research has revealed several insights. For starters, the health problems of obesity are commonly attributed to either of two things:
- Increased size of fat cells. Enlarged fat cells increase the release of chemicals. (This is linked to health conditions such as cardiovascular disease, gallbladder disease, cancer, diabetes, or fatty liver disease.
- Increased amount of fat cells (This is linked to to issues such as the stigma caused by higher body weight, sleep apnea, or osteoarthritis)
One characteristic of obesity that ties almost all of these other associated conditions together is that it is a chronic low-grade inflammatory disorder. Many of us are familiar with the classic inflammatory response that our body undergoes when resolving an injury, such as a cut. However, obesity inflammation has some unique characteristics of its own.
One fact about obesity that needs to be better understood by the world's population is that fat tissue is not merely a storage depot. It is like a metabolically active factory that produces and releases inflammatory chemicals that can contribute to disturbances in other parts of the body.
In fact, most scientists agree that it is appropriate to even view fat as its own endocrine organ or gland because of the fact that it produces hormones and chemical substances that can, as this article has shown, significantly affect health in other parts of the body.
More research is still needed on all the different hormones and chemicals produced by fat mass and the effects of all of these. Still, research is showing they can affect the production and function of other body hormones and organs.
The Good News
Thankfully, certain lifestyle habits help us fight excess body fat, especially the fat that accumulates around the waist. This is the fat we can't pinch, the fat that accumulates deeper in the belly, around organs, which is known to be the most dangerous of all.
Regular, moderate physical activity and a healthy diet can help with reduction of body fat, especially in the belly.
Uranga, R. M., & Keller, J. N. (2019). The Complex Interactions Between Obesity, Metabolism and the Brain. Frontiers in neuroscience, 13, 513. https://doi.org/10.3389/fnins.2019.00513
Daniel G. Amen, Joseph Wu, Noble George, Andrew Newberg. Patterns of Regional Cerebral Blood Flow as a Function of Obesity in Adults. Journal of Alzheimer's Disease, 2020; 1 DOI: 10.3233/JAD-200655
Cherbuin, N., Sargent-Cox, K., Fraser, M., Sachdev, P., & Anstey, K. J. (2015). Being overweight is associated with hippocampal atrophy: the PATH Through Life Study. International journal of obesity (2015), 39(10), 1509–1514. https://doi.org/10.1038/ijo.2015.106
George A. Bray, Medical Consequences of Obesity, The Journal of Clinical Endocrinology & Metabolism, Volume 89, Issue 6, 1 June 2004, Pages 2583–2589, https://doi.org/10.1210/jc.2004-0535