When you are stressed do you tend to eat everything in sight, in a mindless mechanical way?
Or are you on the opposite side of the scale, not hungry, and too stressed to eat a thing, and just happen to nibble 3,000 calories’ worth of food a day. And those of us who really can’t eat a thing. Except for chocolate-chocolate chip hot fudge sundaes. With whipped cream and nuts.
The official numbers are that stress makes about two-thirds of people hyperphagic (eating more) and the rest hypophagic.
So we can conclude with scientific certainty that stress can alter appetite. Which doesn’t teach us a whole lot, since it doesn’t tell us whether there’s an increase or decrease.
It turns out that there are ways to explain why some of us become hyper- and others hypophagic during stress.
During a stressor, appetite and energy storage are suppressed, and stored energy was mobilized. Thus, what’s the logic during the post-stress period?
Obviously to recover from that, reverse those processes.
Block the energy mobilization, store the nutrients in your bloodstream, and get more of them. Appetite goes up. This is accomplished through some endocrinology that is initially fairly confusing, but is actually really elegant.
The confusing issue is that one of the critical hormones of the stress-response stimulates appetite, while another inhibits it.
The type of stressor is key to whether the net result is hyper- or hypophagia. Take some crazed, maze-running rat of a human.
He sleeps through the alarm clock first thing in the morning, total panic. Calms down when it looks like the commute isn’t so bad today, maybe he won’t be late for work after all.
Gets panicked all over again when the commute then turns awful. Calms down at work when it looks like the boss is away for the day and she didn’t notice he was late.
Panics all over again when it becomes clear the boss is there and did notice. So it goes throughout the day. And how would that person describe his life?
“I am like, SO stressed, like totally, nonstop stressed, 24/7.”
But that’s not really like totally nonstop stressed. Take a whole body burn. That’s like totally nonstop stressed, 24/7.
What this first person is actually experiencing is frequent intermittent stressors. And what’s going on hormonally in that scenario?
Frequent bursts of CRH release throughout the day. As a result of the slow speed at which glucocorticoids are cleared from the circulation, elevated glucocorticoid levels are close to nonstop.
Guess who’s going to be scarfing up Krispy Kremes all day at work? So a big reason why most of us become hyperphagic during stress is our westernized human capacity to have intermittent psychological stressors throughout the day.
The type of stressor is a big factor. Another variable that helps predict hyperphagia or hypophagia during stress is how your body responds to a particular stressor.
Put a bunch of subjects through the same experimental stressor (for example, a session on an exercise bicycle, a time-pressured set of math questions, or having to speak in public) and, not surprisingly, not everyone secretes the exact same amount of glucocorticoids.
Furthermore, at the end of the stressor, everyone’s glucocorticoid levels don’t return to baseline at the same rate.
The sources of these individual differences can be psychological, the experimental stressor may be an utter misery for one person and no big deal for another.
Differences can also arise from physiology, one person’s liver may be pokier at breaking down glucocorticoids than the next person’s.
What else separates the stress hyperphagics from the stress hypophagics?
Some of it has to do with your attitude toward eating. Lots of people eat not just out of nutritional need, but out of emotional need as well.
These folks tend both to be overweight and to be stress-eaters. In addition, there’s a fascinating literature concerning the majority of us, for whom eating is a regulated, disciplined task.
At any given point, about two-thirds of us are “restrained” eaters. These are people who are actively trying to diet, who would agree with statements like, “In a typical meal, I’m conscious of trying to restrict the amount of food that I consume.”
Mind you, these are not people who are necessarily overweight. Plenty of heavy people are not dieting, plenty of everyone else is at any point.
Restrained eaters are actively restricting their food intake. What the studies consistently show is that during stress, people who are normally restrained eaters are more likely than others to become hyperphagic.
This makes lots of sense. Things are a bit stressful, corporate thugs have looted your retirement savings, there’s anthrax in the mail, and you’ve realized that you hate how your hair looks.
That’s exactly the time when most people decide that, as a coping device, as a means of being nice to themselves during a tough time, they need to ease up on something about which they’re normally pretty regimented.
So if you normally force yourself to watch Masterpiece Theater instead of reality TV as some sort of gesture of self-improvement, on goes Survivor XII. And if it’s food intake that you’re normally regimented about, out come the fudge brownies.
So we differ as to whether stress stimulates or inhibits our appetite, and this has something to do with the type and pattern of stressors, how reactive our glucocorticoid system is to stress, and whether eating is normally something that we keep a tight lid on.
This information was taken from the book Sapolsky, Robert M.. Why Zebras Don't Get Ulcers (p. 76).