About 2 billion people around the globe are overweight and many of these are obese. That’s 20% of the population. Considering the implications of obesity on our health, this is bad news. We already know that excess body weight negatively affects diabetes, cardiovascular diseases, and some strains of cancer. However, what we don’t know much about is how obesity affects the structure and function of our brain.

Does Excess Body Weight Cause Our Intellectual Capabilities to Decline?

Several studies have shown the correlation between obesity and a lower IQ. The question is, which came first? Are those with lower IQ’s prone to weight gain? Or, does obesity itself cause the decline in intellectual capabilities?

Previous studies had seemed to indicate that lower intellect was brought about by obesity. However, more recently, longitudinal studies have proven this incorrect. In fact, they demonstrated that one of the side effects of excess body weight is a lower IQ.

Low IQ in Childhood Associated with Obesity in Adulthood

There was a meta-analysis, published in 2010 that gave summaries on 26 varied clinical studies on this very subject. The basic conclusion of the study was that there is a strong association between lower IQ levels in one’s childhood and obesity as an adult.

A Study in Sweden

In Sweden, 5286 males were evaluated in a study. Their IQ level at aged 18 and again at aged 40 were tested. Their BMI (body mass index) was also tested. The consensus was that those who had lower IQ’s also had higher BMI levels.

A Study in New Zealand

There was another study done in New Zealand that involved 913 participants. In this study, the subjects’ IQ levels were tested at the age of 3, 7, 9, and 11 years of age and again at the age of 38. As a result, the study confirmed the above results. Lower IQ levels led to higher BMI in each case. Furthermore, those with higher IQ levels had lower BMI levels.

A 50-Year Study in the UK

In a study in the Uk, over 3,000 participants were followed for over 50 years. Subjects had their IQ levels tested at 7, 11, and 16 years of age. Then, when they were 51 years old, their BMI levels were evaluated. These tests clearly showed that your IQ level at aged 7 will determine whether or not your BMI level at age 51 is healthy or not. Additionally, the results showed that, after 16 years of age, BMI grows more quickly in those who have lower IQ’s.

Another UK Study

Yet another trial was conducted in the UK which involved 17,414 people. In this study, IQ was tested at age 11 and their BMI at 16, 23, 33, and 42 years of age. This test also showed that a lower IQ during childhood results in overweight and obesity in adulthood.

Faster Brain Aging for the Obese

It’s quite natural for the brain to age. It actually loses white matter and begins to shrink. However, not everyone’s white matter shrinks at the same rate. And, obesity speeds it up, sorry to say. It’s true. Of course, there are other factors involved in speeding up the loss of brain cells, but excess body weight is certainly one of them.

At the University of Cambridge, a study took place that evaluated the brain structure of 473 subjects. The conclusion of this study also proved that obese people possess a smaller amount of white matter compared to those with normal weight. In fact, the data revealed that obese people’s brains were up to a decade older anatomically that those with normal weight.

In another study, scientists measured BMI in 733 middle-aged persons. They also measured their waist circumference, and waist-to-hip ratio.  To identify and compare the signs of brain degeneration, they also took an MRI of each of the subject’s brain. The goal of the study was to determine whether there was a link between obesity and a loss of brain mass. The scientists reported that brain loss was greater in those with higher BMI, waist circumference, and waist-to-hip ratio than those with normal measurements.  They summised that this degree of brain cell loss could possibly lead to dementia, although there is not direct evidence for this hypothesis.

Obesity Alters our Feelings

Since we now know that obesity changes the brain’s structure, it’s safe to assume that it also has an affect on the way the brain functions. And, since our feelings are largely controlled by neurotransmitters, such as dopamine, it’s interesting to note that concentrations of dopamine correlate to BMI, isn’t it? That means that those who have a higher BMI will also have less available dopamine.

The Jolly Fat Man May be Lacking Dopamine

And, since dopamine is the neurotransmitter responsible to make us happy and motivated, that means the picture of the jolly fat guy we have in our heads is largely a myth. Sorry, Santa. You may be saying, “Ho, ho, ho,” but, that’s not really how you feel, is it? In fact, that lack of dopamine may lead to an insufficient amount of pleasure from eating which leaves Santa with the urge to eat excessively to try to feel satisfied.

What a vicious cycle. He’s obese because he eats too much because of a lack of dopamine, but his obesity lowers the dopamine rather than increasing it. Poor Santa.

Those Who Overeat Enjoy Food Less

Studies have shown that obese individuals enjoy their food less than people with lean bodies simply because those who were overweight possessed less dopamine receptors in their brain.

Excess Body Weight is Bad for the Brain

Think about it. These findings are a clue into an alarming truth. We have the evidence to say that obesity negatively affects our brain. But, if physical exercise can strengthen the heart and make it younger, perhaps there’s hope that losing weight and getting stronger could also have beneficial effects on the brain. If that’s the case, keeping fit is smart.

You May Also Like: