Anecdotally, the stress/eating connection makes some sense. I know of a lot of study sessions that are accompanied by a doughnut or two. Or, let’s take people who have high stress jobs: in many cases, a 10 to 20 pound weight gain is typical after the six month honey moon in a career in banking or law.
However, there are other instances where much larger amounts of weight are gained as product of a hugely stressful environment. If the fight or flight response was supposed to work, how can weight gain in response to stress be true? I’m skeptical every time someone tells me ‘stress’ is the reason for extreme weight loss, and here’s why.
What is stress?
Stress occurs in the face of uncontrollable events that pose a threat to your survival. Whether it’s real or perceived isn’t really the issue; any overwhelming emotional or physiological event that forces your body to react, and consequently recalibrate its equilibrium, can be considered highly stressful. Loss of a job, family member, dramatic change to your social or financial landscape… these will elicit that infamous adjective, ‘stress’. In order to adjust, your body engages in what is called ‘allostasis’ which is the body’s ability to achieve physiological stability through change in internal milleu and adjustment to a new physiological set point.
The adjustment comes with a price: increased ‘wear and tear’ to your coping skills, a decrease in immunological defense, and perhaps increased impulsivity. Let me explain how stress can manifest in behavioural change, which may prevent many people from being able to simply Eat Less and Move More.
Stress and overeating
Acute stress will have an effect on eating behaviour. If stress is extreme, you may forego eating for entire parts of the day. However, the whole ‘weight loss due to stress’ phenomena is largely overrated. Chronic stress is one of the key ingredients to weight gain, and I’d like to explain how some of that occurs.
To start, stress is associated with binge eating, increased consumption of hyper palatable food, meal skipping, increased snacking and… do I need to bring up binge eating again? Stress induced eating may be different for obese versus lean people, too. Some obese people show a strong tendency for stress eating in the presence of worry, whereas lean seem to avoid food altogether.
The biology of stress eating
Two key systems here: The hypothalamic pituitary adrenal axis (HPA axis), which stimulates the release of stress hormones (like corticotropin-releasing factor and adrenocroticotrophin hormone), and also the autonomic nervous system. Both stress pathways influence inflammation and immunity.
Both food restriction and high fat diets alter HPA axis response to stress, and we also know comfort foods suppress activity within the HPA, effective immediately. Chronic and high levels of repeated and uncontrollable stress results in dysregulation of the HPA axis, and this can in turn affect energy homeostasis and eating behaviour. Chronic activation of the HPA axis (chronic stress, by the way) promotes insulin resistance, and also alters the activity of appetite related hormones (ghrelin, leptin) and feeding neuropeptides. One way to reduce HPA activity quickly, is with comfort foods. They numb the HPA axis, which might explain part of their analgesic effects (which can also be traced to the release of endeogenous opioids, which accompanies any food that is high in sugar and fat).
… Basic science studies have also shown stress also effects cortico-limbic areas of the brain that modulate food reward and craving. These types of studies are more interesting, as they suggest chronic stress is a culprit in decreasing emotional, visceral, and behavioural control and also increasing impulsivity. Impulsivity is of course associated with increased intake of alcohol, cigarettes, and of course, hyper palatable utlra rewarding food.
So, if a person is not by nature impulsive, chronic stress may play an important role here. Chronic stress may lead to increased impulsivity, which in turn manifests itself in the selection of ‘escapist’ behaviour. This may also explain huge weight loss issues in the case of high stress professionalism: drugs of abuse may be used in order to cope with ‘the daily grind’.
What to do?
With the litany of consequences associated with chronic stress, one small piece of advice is this: so many of our biggest life stressors are imagined. Part of being human includes having an incredible imagination, and ability to plan for ‘future events’. Yet, so many of the imagined future events never occur. Take the weekend to try and think about… nothing! One way to achieve this is by getting outside, getting your running shoes, and looking at the sky. Or bludgeoning your body with so much exercise you can’t see straight! Do it for your head, not necessarily just your heart. Doing absolutely nothing but intense physical activity may soon be the best advice we have in the face of near constant reminders of ‘stress’.
Another thing? Turn off your iphone.
Have a great weekend.