This is part 2 in a 4-part series on chronic stress and belly fat. If you missed part 1 you can find it here.
If you’ve suffered from chronic stress you’ve probably experienced some of these symptoms: anxiety, depression, fatigue, headaches, digestive disorders, loss of concentration or motivation, disrupted sleep patterns, and high blood pressure.
They are the most common symptoms of chronic stress.
There are a few others that are not thought of as critical as the above but can be quite damaging in their own right.
Have you noticed that your appetite increased when you were under stress?
That wouldn’t be unusual because research has shown that chronic stress is associated with an increased appetite.
How about weight gain?
Have you noticed a gain of inches in your midsection while undergoing a stressful period?
Weight gain is also a very common occurrence with chronic stress.
However, weight gained from chronic stress can result in excess abdominal fat and might be a signal that dangerous metabolic processes are taking place in your body.
Let’s take a look.
Subcutaneous Fat Versus Visceral Fat
In last week’s post, I examined a recent study by the University College of London that showed that there’s a high association between chronic stress (as measured by high cortisol hormone levels) and weight gain.
Interestingly, they found that weight gain from stress did not manifest in an increase in subcutaneous fat.
Subcutaneous fat is that pinchable and squishy type of fat that accumulates under your skin.
It provides insulation from the cold, cushioning for your body, storage for extra calories, and is generally found in the arms, legs or buttocks.
In the above study, researchers discovered that weight gained from chronic stress was expressed as fat around the abdominal area.
This type of fat, known as visceral fat, is firmer to the touch and lies deeper in your mid-section.
It can often accumulate around your organs and is considered dangerous by health practitioners.
In a statement concerning the above study, lead researcher Dr. Sarah Jackson commented on the danger of belly fat,
People who had higher hair cortisol levels also tended to have larger waist measurements, which is important because carrying excess fat around the abdomen is a risk factor for heart disease, diabetes, and premature death.
Dr. Jackson’s assessment of excess abdominal weight is quite accurate as research has consistently shown that individuals with a high hip-to-weight ratio are more likely to suffer higher rates of cardiovascular disease, type 2 diabetes, cancer, and mortality.
How Do You Know If You Have Too Much Visceral Fat?
The only way to absolutely know how much visceral fat you have is by performing a CT scan.
However, if you’re concerned, there is a way to know approximately where you stand.
1. Waist circumference (WC):
Men should have a WC of less than 40 inches (102 cm) and women should have a WC of less than 35 inches (89 cm).
2. Waist-to-Hip Ratio:
The waist-to-hip ratio (WHR) takes the circumference of your waist (see above) and divides it by the circumference of your hips.
WHR = (Waist circumference) / (Hip circumference).
Men should have a WHR of less than 1 while women should have a WHR of less than 0.8. For how to measure your WHR see here.
3. Your body type
People with a pear shaped body tend to store fat in the lower extremities (hips, thighs, buttocks) as subcutaneous fat.
People with an apple shaped body tend to store fat in the upper region (belly, chest) as visceral fat.
Of course, this last method of determining is not as perfect as the previous two.
Here is something important to remember. You can have a normal body weight and still have too much visceral fat.
Okay, let’s get into what’s going on with the accumulation of abdominal fat.
Does Chronic Stress Actually Cause Weight Gain?
Jackson’s study, while demonstrating a high correlation between chronic stress and abdominal weight gain, didn’t actually show a direct link between the two.
As any good scientist is quick to point out, correlation doesn’t prove causation.
Some researchers have argued that stress and high cortisol levels might just be a secondary result of obesity.
To my knowledge, there hasn’t been a study done that shows a direct link between chronic stress and weight gain.
This is probably because the cost and technicalities of performing such a study are prohibitive.
However, by deduction, we can show that chronic stress does cause weight gain and in the process create other health problems.
Excess Cortisol Is The Connection Between Stress And Weight Gain
In the above study, the link between chronic stress and weight gain was demonstrated by chronically elevated levels of the stress hormone cortisol.
People who had higher levels of cortisol [emphasis mine] present in their hair sample tended to have a larger waist circumference, were heavier, and had a higher BMI, indicating more body fat as opposed to muscle.
It appears that cortisol is the connection between chronic stress and weight gain.
So the important question is does cortisol cause weight gain.
Excess Cortisol Causes Weight Gain
Cortisol is part of a class of steroid hormones called glucocorticoids
A synthetically produced glucocorticoid that acts in the same manner as cortisol is prednisone.
Prednisone is often used to treat a number of inflammatory diseases.
One of the side effects of administering prednisone in humans is unwanted weight gain.
This extra weight usually manifests as fat around the face, back, shoulders, and abdomen.
Therefore, glucocorticoids, of which cortisol is a member, cause weight gain when administered systemically in the body.
Interestingly, Cushing’s Syndrome, a disease involving excess cortisol production, often produces this same type of weight gain.
Conversely, Addison’s Disease, a disease of too little cortisol, causes weight loss.
So this is what we know so far:
- Excess cortisol is highly associated with weight gain.
- Prednisone a type of cortisol produces weight gain.
- A disease that causes the over-production of cortisol results in weight gain.
- A disease that causes a lack of cortisol results in weight loss.
I think it’s safe to say that excess cortisol causes weight gain.
Most experts will tell you that weight gain from prednisone is caused by increased appetite and water retention.
While these side effects do play a role in weight gain, I don’t believe they are the main drivers of weight gain from cortisol.
In part 3 of this series, I’ll look at the relationship between stress and appetite.
The reason for weight gained from cortisol is much more insidious and lies in one of the side effects of glucocorticoids.
These two processes are critical to understanding how cortisol causes weight gain.
They are also critical to understanding why chronic stress can be so dangerous.
Let’s unpack this by first seeing what cortisol does to your body during acute stress.
Cortisol: The Stress Hormone
Cortisol, also known as the “stress hormone”, is produced in humans by the cortex of the adrenal glands.
One of its main functions (along with epinephrine) is to modulate your “flight or fight response”.
When your brain perceives a stressful or dangerous situation, it initiates a series of metabolic responses designed to allow you to survive the danger.
Some metabolic processes like digestion, growth, reproduction and the need for sleep are suspended.
Others that are normally inactive are immediately activated in order to allow you to survive the threat.
Let’s suppose you’re hiking in beautiful Yellowstone Park and happen to come upon a grizzly bear.
Your brain recognizes the danger (as it should if you saw The Revenant) and immediately prepares your body to fight or flee from the bear.
First, it initiates a cascade of hormones that eventually stimulate the release of cortisol from your adrenal glands.
Cortisol then becomes active in providing energy in the form of glucose to your large muscles by:
1. Releasing glucose from the liver (gluconeogenesis)
2. Stimulating the breakdown of fatty acids from adipose tissue and amino acids from muscle (the substrate for gluconeogenesis)
3. Inhibiting glucose uptake in peripheral tissues
4. Resisting insulin activity
Now that you have all that extra energy in your muscles, you can either outrun the bear or fight it (and hope you don’t fall prey to Leo’s fate in The Revenant).
Good luck with that.
Once you’ve escaped the bear, your brain perceives that the danger is over and your cortisol levels fall back to normal.
The physical exertion you generated will use up the extra glucose in your bloodstream.
It’s a beautifully designed system.
However, what if the threat or stressor is not a physical one but a psychological one?
Cortisol, which can be a life savior during acute stress, can now become a menace during chronic stress.
The Cortisol-Insulin Connection
When the body is under acute stress, cortisol moves energy out of storage (e.g. the liver) into a readily usable form such as glucose.
Insulin’s job, on the other hand, is to move glucose out of the blood and into other areas of the body for storage (primarily muscle cells, fat tissue, and the liver).
During short-term stress, cortisol and insulin appear to have the opposite effect.
However, during chronic stress, the interplay between cortisol and insulin is more complicated.
Chronic psychological stress from stressors such as relationship problems, work issues, or financial matters can last for months or years and can result in chronically elevated cortisol levels.
When cortisol levels remain high, the liver is continually stimulated to release glucose into the bloodstream.
However, because this stress is psychological in nature, there is no resultant physical exertion to use up this excess glucose
This results in high blood glucose levels.
Since excess glucose in your blood is toxic, your body has to remove it.
This is where insulin steps in.
Cortisol Causes Increased Insulin Levels
In order to move the excess glucose from the blood into storage, your body signals the pancreas to increase the secretion of insulin.
Initially, your cells can store extra glucose. However, cortisol is continuing to tell the liver to release more glucose into your blood stream.
Over time, muscle cells and the liver, which have a limited storage capacity, start to become full and resist the effects of insulin.
Fat cells, which have greater storage capacity, are happy to take up the extra glucose. But that fat gets locked in your fat cells by insulin.
You know what that’s going to cause. That’s right: weight gain.
As this process continues, your cells eventually become packed with glucose. They don’t want anymore.
They reject more glucose by becoming increasingly resistant to insulin.
However, your body has to get rid of the extra blood glucose. Your pancreas now expresses itself with more force.
It releases more insulin in an attempt to pack more glucose into the cells.
It’s like when Mom and Dad need to raise their voices because their child hasn’t done what was asked the first time. Hopefully, a stronger response will work
But this only leads to more insulin resistance and subsequently more insulin secretion.
More resistance will lead to higher blood glucose levels and gradually weight gain increases.
However, continually higher blood glucose levels will just lead to an increase in insulin. Thus, the cycle continues.
Incidentally, research has also shown that glucocorticoids can directly cause insulin resistance in skeletal muscle by interfering with insulin signaling.
Several studies have confirmed that cortisol is a major factor contributing to insulin resistance. Also see here.
Insulin Resistance Is Time Dependent
It’s important to note that insulin resistance doesn’t happen overnight. It’s time dependent.
In other words, people who develop insulin resistance may initially have normal or close to normal blood glucose levels.
These levels remain low due to the excessive release of insulin, which is trying to maintain balance in the bloodstream.
However, if cortisol levels are not normalized, over time blood glucose and insulin levels can rise to a level where insulin resistance is created.
While chronically high cortisol levels can induce insulin resistance, they are not the prime driver of insulin resistance.
The prime driver of insulin resistance appears to be a diet high in fructose (not from fruit), sugar, and refined carbohydrates.
Therefore, if you’re eating a poor diet and are also undergoing a time of chronic stress, you could be creating a situation where significant weight gain and other health problems could occur.
The Danger Of Insulin Resistance
Insulin resistance is a serious problem regardless of its origin. A 2015 JAMA study estimates that up to 50% of the American population is insulin resistant.
Insulin resistance is a hallmark of type 2 diabetes and is also highly associated with prediabetes.
Researchers estimate that 86 million adults aged 20 years and older have prediabetes.
A recent University of Florida study revealed that up to 33% of prediabetics are normal weight but have a high proportion of fat to lean muscle.
People who have insulin resistance are also at a higher risk of developing type 2 diabetes, CVD, metabolic syndrome, cancer, and obesity.
It’s not difficult to see why anything that creates insulin resistance including chronic stress can be metabolically devastating.
Insulin Resistance And The Liver
Let’ take a second to consider the liver.
Your liver will absorb glucose and convert it to glycogen.
However, once your liver has maxed out its glycogen storage (true of most people), it will begin to create fat and export it to other parts of the body.
Fat cells, especially those around the abdomen, seem to have a unique affinity for that fat.
Since the liver also doesn’t want excess glucose, it also can become insulin resistant. This further increases insulin levels.
Also, if the liver can’t export fat fast enough, it will store this fat, causing a condition known as non-alcoholic fatty liver disease (NAFLD).
NAFLD is associated with metabolic syndrome, obesity, hyperlipidemia, type 2 diabetes, and high blood pressure.
While there may be other pathways yet to be discovered that link high cortisol to weight gain until there is definitive evidence demonstrating how cortisol causes weight gain these mechanisms seem most plausible.
See Dr. Peter Attia’s TED talk on insulin resistance.
Chronic Stress causes increased cortisol levels. These increased cortisol levels could, in turn, create insulin resistance.
As we’ve seen, insulin resistance has the potential to cause several metabolically dangerous situations.
If you’re undergoing chronic stress and you’re starting to see weight gain, then it’s paramount to get that stress under control.
I know it’s a lot easier said than done.
If you think any of this applies to you or you think you may be a candidate for type 2 diabetes or prediabetes make sure you see your health professional. And make sure you have an A1C test performed.
In part 3 of this series, I’ll look at how cortisol can increase appetite and thus increase weight gain. I’ll give you some practical things you can do to alleviate chronic stress and the complications caused by it.
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