Stress and Weight Gain

It's well known that there is an association between stress and weight gain, and our eating pattern is influenced by the different crises that we inevitably face in our daily life.

However, how this correlation works is less obvious because not every stressed individual has necessarily a bigger appetite. In fact, many people eat less, and consequently lose weight during some distressing events.

So what factors influence this non-linear correlation between stress and weight gain? To answer this question, we need to understand first the physiological changes that occur during a stressful period.

This includes the stressor itself, which can be a real fight or a ridiculous dispute for the microwave in the lunch room, a heavy set of squats, etc, and the post-stress recovery period.

Your body perceive the actual stressor as a crisis it has to cope with, so logically appetite and energy storage are suppressed, and all available energy is mobilized for this purpose.

Insulin secretion drops, blood flow in nonessential body parts (such as stomach) decreases dramatically, and stress hormones are released. As a consequence, you feel more invigorated, and eating is the last thing in your mind. So then why stress and weight gain are associated?

Conversely, during the stress recovery period all these effects are reversed. Appetite increases because the energy wasted during the short term crisis has to be restored. Therefore, insulin levels increase, energy mobilization is halted, and more nutrients are stored in the blood stream.

Two important hormones that regulate this process are CRH (corticotropin releasing hormone) and cortisol (there is actually a third one, but for the sake of simplicity we'll just ignore it). By looking at these hormones we can understand the above variance because they have completely opposite effects on appetite.

When something stressful happens, your hypothalamus secretes immediately CRH, which causes a chain reaction that within a few minutes stimulates adrenal gland to release cortisol.

Now, how these hormones influence appetite depends on their timing. If you have a large amount of CRH floating around but almost no cortisol, you are probably at the beginning of a critical event that, under normal circumstances, shouldn't last more than a couple of minutes.

Consequently, you feel very aroused, and appetite is turned off because your priority is to save your ass.

However, as CRH returns rapidly to its base level, cortisol continues its ascension, and at some point becomes predominant. From an evolutionary perspective, you are now searching for food in order to replenish the wasted resources, so you'll still feel alert but also hungry.

Is important to note that the cortisol is not cleared from your bloodstream within a few minutes as it happens with the CRH (10k years ago there was no Burger King around the corner). Normally, it lingers in your bloodstream for a few hours during which appetite is greatly stimulated.

Now, looking at this model (which is superbly explained in Robert Sapolsky's Why Zebras Don't Get Ulcers) the link between stress and weight gain becomes more transparent. Of course, most of us don't experience life threatening crises on a daily basis.

However, as we haven't quite adapted to modern life stressors, your body doesn't make a big difference between a ferocious beast and your retarded manager.

How often do you feel like throwing the keyboard at your boss when he makes the same stupid jokes about the bad weather? Or even worst, when you are anxious because it's almost the end of the month, and you haven't even started most of your projects. I bet your boss wouldn't laugh about that.

How many times while being stuck in a traffic jam you slammed the wheal and cursed the person in front of you?

All these intermittent stressors will trigger a constant on/off secretion of CRH, and as a result cortisol will be chronically high along with insulin – which will make you crave comfort foods high in sugar and fat.

So what's the big deal if you indulge yourself with a piece of chocolate or a few cookies when life struggles seem insurmountable?

Well, there is no problem as long as it doesn't become a habit. In fact, having a few bites of your favorite food has a positive effect on the stress response, and makes you feel better.

However, research shows that restraint eaters tend to go overboard. Instead of being nice with themselves, they gorge thousands of calories in one sitting, and end up felling worst.

So mainstream diets will cause stress and weight gain, (particularly abdominal fat), which leads to a progressive insulin resistance. It should be noted that, besides the fat stores, insulin secretion is also influenced by cortisol, and both play an important role in regulating calorie intake. (You can find relevant research here, here and here.)

“It appears that insulin plays a profound role in food selection, while GCs determine the motivation for selecting these foods, perhaps through their actions on dopamine secretion in the nucleus accumbens.” (Dallman, 2011)

Therefore, you should forget about any restrictive diet such as low “something” because, instead of durable weight loss, the reward for your efforts will be an ever increasing belly. You will become even more stressed, insulin resistance will accentuate, and that's how you get in a vicious circle.

I was mentioning that most modern stressors have an intermittent occurrence, and are an inevitable part of our daily lives. It would very simplistic to tell you to relax or get into meditation. You wouldn't give a shit about such an advice, and you shouldn't. 

There are so many people who just know what is better for you, or what you should do, and who in fact have miserable lives themselves. So I will tell you only one thing about stress and weight gain.

Most of these intermittent stressors are just puerile. Whenever you feel anxiety or anger, just take an imaginary step backward so you can see the big picture. You'll suddenly realize that things are not as bad as you perceive them. 

You can always look for a different job, and tell your boss to fuck off. You'll realize just how silly is to get upset because of a traffic jam. You'll became more calm and lucid in evaluating any given situation.

So don't let deluded perceptions to become your reality, and don't let stress and weight gain to become your problem.

Return from Stress and Weight Gain to Home