In the first part of this series on diabesity, we “got under the hood” to look at the underlying mechanisms of both obesity and diabetes. We’ve now moved on to discussing the environmental and lifestyle risk factors that drive these conditions. In the last article we learned about the top 3 dietary causes of diabesity. In this article, we’re going to see how stress can independently cause both obesity and diabetes.
A huge – and I mean huge – amount of research over the past two decades shows that stress causes both obesity and diabetes in a variety of ways. Studies also show that stress makes it hard to lose weight. This is one reason why some people just can’t seem to lose weight no matter how well they eat or how much they exercise. I believe stress is one of the most important – yet most often ignored – factors driving the diabesity epidemic.
Stress is a bigger problem than you think
Hans Selye, the famous physiologist who coined the term “stress”, defined it this way:
…the nonspecific response of the body to any demand made upon it.
The prominent psychologist Richard Lazarus offers a similar definition:
…any event in which environmental demands, internal demands, or both tax or exceed the adaptive resources of an individual…
Most people only think of psychological stress when they hear the term “stress”. When asked what causes stress, they might say things like losing a job, having a fight with your spouse, driving in traffic or getting audited by the IRS.
While it’s true that psychological challenges like this are major stressors, what many people don’t realize is that stress is also caused by physiological challenges, such as:
- chronic infections
- autoimmune disease
- environmental toxins
- too much exercise
Even if your levels of psychological stress are pretty low, any of the conditions listed above can provoke a chronic stress reaction in your body. And as we’ll see in the next section, chronic stress can make you both fat and diabetic.
10 ways stress makes you fat and diabetic
When stress becomes chronic and prolonged, the hypothalamus is activated and triggers the adrenal glands to release a hormone called cortisol. Cortisol is normally released in a specific rhythm throughout the day. It should be high in the mornings when you wake up (this is what helps you get out of bed and start your day), and gradually taper off throughout the day (so you feel tired at bedtime and can fall asleep).
Recent research shows that chronic stress can not only increase absolute cortisol levels, but more importantly it disrupts the natural cortisol rhythm. And it’s this broken cortisol rhythm that wreaks so much havoc on your body. Among other effects, it:
- raises your blood sugar
- makes it harder for glucose to get into your cells 1
- makes you hungry and crave sugar
- reduces your ability to burn fat
- suppresses your HPA-axis, which causes hormonal imbalances
- reduces your DHEA, testosterone, growth hormone and TSH levels 2
- makes your cells less sensitive to insulin
- increases your belly fat and makes your liver fatty
- increases the rate at which you store fat
- raises the level of fatty acids and triglycerides in your blood
Each one of these consequences alone could make you fat and diabetic, but when added together they’re almost a perfect recipe for diabesity.
Our bodies aren’t made for chronic stress
One of the reasons chronic stress is so destructive is that our bodies didn’t evolve to deal with it. We’re set up to handle short-term, acute stress fairly well. In paleolithic times, this might have been caused by getting chased by a lion or hunting for our next meal. In fact, this type of stress may even be beneficial for our bodies because it improves our ability to react to the challenges of life.
What we’re not adapted for, however, is the chronic, unrelenting stress that has become so common in modern life. This type of stress provokes feelings of hopelessness and helplessness – what psychologists call a “defeat response”. And it’s the defeat response that leads to increased fat storage, abdominal obesity, tissue breakdown, suppression of the immune system, and all of the other effects I listed above that directly cause obesity and diabetes.
A closer look at insomnia, dieting and exercise
I’d like to take a closer look at three often stressors that can make us fat and diabetic: insomnia, dieting and exercise.
More than a third of American suffer from insomnia, with 42 million prescriptions for sleeping medications filled in 2007. Several studies show that sleep deprivation elevates cortisol and makes it more likely that you’ll get fat and develop diabetes.
A very recent paper showed that restricting sleep to 5 hours a night for just one week significantly reduces insulin sensitivity. Another study earlier this year showed that even one night of sleep loss increased appetite in young, healthy adults. Sleep restriction is associated with impairment of carbohydrate tolerance, and research has shown that a loss of 3 hours of sleep each night causes a weight gain of 4-5%.
It’s estimated that between 50-60% of Americans are dieting at any given time. That’s a huge number. And while it may seem counter-intuitive that dieting contributes to obesity and diabetes, it makes perfect sense when you understand that dieting is a stressor that disrupts our cortisol rhythm.
A 2001 study showed that “cognitive dietary restraint” (translation: stressing about food or doing overly restrictive diets) raises your cortisol levels. Studies have also shown that caloric restriction – as is common in low-fat diets – increases cortisol levels. And a recent study reported on by Stephan Guyenet at Whole Health Source found that caloric restriction is especially harmful when combined with sleep deprivation.
Finally, although not common in the general population, too much exercise can also predispose you to weight gain and diabetes by raising cortisol levels, breaking down muscle tissue and increasing fat storage. This is especially true if cortisol levels are already elevated or disrupted by other stressors like gut infections, insomnia, food toxins or psychological factors.
It’s not uncommon (in the paleo/fitness subculture, at least) to encounter someone who eats well and exercises their brains out, but cannot lose weight. In fact, several of my patients fall into this category. They are often surprised when I tell them they need to exercise less if they want to lose weight and recover their health. What they may not realize is that cortisol is a catabolic hormone. It breaks the body down.
While this might sound like a good thing for those trying to lose weight, it’s not. Muscle tissue is metabolically active and actually helps us lose weight. A reduction of lean muscle tissue may drop a few pounds in the short-term, but it will predispose you to weight gain in the future by impairing your metabolism. (This is another reason why caloric restricted diets, which break down muscle tissue, don’t work in the long-term and even make things worse.)
So if you’re struggling with weight or blood sugar control, don’t diet, get plenty of sleep and take it easy with exercise. You’ll be a lot better off.