We’ve all had those days: Your morning starts by spilling coffee on your clothes. You have to change, making you late for work. Then, you get dragged into a meeting you definitely weren’t prepared for and realize you also forgot your lunch (because you were in such a hurry due to the coffee fiasco) so you have to spend way too much on a soggy sandwich. Then, 20 minutes before you’re about to leave, your boss gives you an assignment that’s bound to take you hours.
After a day like this, some people turn to comfort food, like a slice of cheesy pizza or a pint of ice cream, while others decompress by sweating it out. Why is that?
It has a lot to do with hormones and psychology. In order to understand how your body reacts to stress, you need to understand how these factors come into play.
When experiencing acute stress, your body is thrown into “fight or flight” mode. Your endocrine system starts pumping out adrenaline (epinephrine), which puts your eating on hold (no time to eat if you’re running from a hungry tiger!). But if this level of stress continues for too long, these hormones will cause some serious damage, so your body needs to calm down, or at least shift to a set of hormones better suited for long-term stress. It does this by releasing noradrenaline (norephinephrine), and cortisol. According to a Harvard Mental Health Letter, “Cortisol increases appetite and may also ramp up motivation in general, including the motivation to eat. Once a stressful episode is over, cortisol levels should fall, but if the stress doesn’t go away — or if a person’s stress response gets stuck in the “on” position — cortisol may stay elevated.”
So does chronic stress makes you crave fatty, sugary foods? Because these foods have more calories—and more calories means more energy to handle your stressful task—some research shows cortisol can make you crave them. But you also crave these “comfort foods” because you (and your body) know they make you temporarily happier. As stated in the Harvard Mental Health Letter, “Fat- and sugar-filled foods seem to have a feedback effect that inhibits activity in the parts of the brain that produce and process stress and related emotions.” If cheesy fries make you feel better, then it seems like a no-brainer to eat them when you want to calm down. “When you’re stressed, you’re uncomfortable by definition,” says Denis Faye, TK’s Director of Nutrition. “So it just makes sense that your brain would crave some relief, no matter how temporary.”
If stress keeps you from sleeping well, then there’s another hormone that can wreck havoc on your appetite. Researchers at Louisiana State University examined the connection between sleep, hormones, and weight gain, and found that sleep deprivation is associated with higher levels of the hormone ghrelin (which tells you to eat), increased hunger, and higher BMI. “Even a single night of sleep deprivation appears sufficient to increase ghrelin and hunger.” According to the study, restricting sleep especially increased hunger and appetite for calorie-dense, high carbohydrate foods.” (a.k.a. cheesy fries.)
A group of Korean researchers recently found similar results. “Growth hormones, melatonin, cortisol, leptin, and ghrelin levels are highly correlated with sleep and circadian rhythmicity,” they stated in their study. Faye explains that being sleep deprived stimulates the production ghrelin, and it decreases the levels of leptin (which tells you to stop eating). “In other words, when you don’t get your seven or eight hours of sleep, your hormones send signals to your brain to eat more,” he says.
However, in times of stress, some people consume comfort food, while others don’t eat much at all. These reactions have a lot to do with how you’ve been conditioned to deal with stress.
A study published in Psychological Science, found that many people can be put into one of two groups: “munchers” and “skippers.” Munchers eat more when they’re stressed and less when they face a positive situation. On the other hand, “skippers” eat less when they’re stressed and more when they’re not. “If food isn’t a comfort source for you, it makes complete sense that you’d stop eating when stressed if you’re focused on the situation,” Faye says.
Other studies have found that habits have a greater influence on how you react to stress.
“Habits are 45 percent of daily life, and they don’t change in high-pressure situations,” says David Neal, PhD in a ScienceDaily article. “People default to what their habits are under stress, whether healthy or not.”
An experiment conducted by Neal and Wendy Wood, at USC, followed students for an entire semester and found that students were more likely to stick to old habits when they were stressed or sleep-deprived. “It was as if they didn’t have the energy to do something new,” Wood says. Students who ate unhealthy foods during the semester ate even more junk food during exams. However, students who ate healthy foods were more likely to eat well when they were under pressure. The same pattern was found with non-eating habits, like exercising. Even with limited time, students who regularly went to the gym during the semester were even more likely to go when they were stressed.
Your brain — especially when it’s tired or stressed – wants to follow the path of least resistance. So if at some point you taught it that candy and cupcakes cheer you up…you’re going to look for them when you’ve had a rough day. But the same goes for a workout. People tend to default on habits during stressful situations because they’re safe and comforting, at least in the beginning. “It’s the same reason people go back to a bad boyfriend or girlfriend,” Faye says. “In a moment of stress, running into the arms of an old flame can be enormously comforting (and kind of fun). But then you wake up the next morning and remember why you left in the first place.”
So, how can you use this information to your advantage? When you’re not in a state of stress, start to reprogram what you turn to for comfort. Ideally, something that doesn’t come in the form of brownies and burgers. “For me, it was exercise,” Faye says. “It took years, but when I’m stressed, the first thing my body wants to do is hop on a bike.” If that doesn’t sound like something you would choose over a chocolate donut, consider meditating, laughing, or spending time with friends. These activities reduce cortisol levels, and they can also just make you feel a whole lot better.