The Science of Stress, Sleep, and Eating

>> Welcome back to our exploration of some of the science behind emotional eating. What if I was to tell you that as a Health Coach, helping your clients stress less and sleep more would solve all of their problems? Okay, that's a bit oversimplified. However, as we'll discuss, it might not be quite as oversimplified as you thought. In this lecture, we're focusing on stress. We talked a lot about stress earlier in the course. But we're going to dive in a bit deeper today, specifically on how stress can biologically affect appetite, food choices and digestion as well as the importance of sleep. Stress is a crucial component of emotional eating. For many people, it's the cornerstone of why they eat the way they do. Stress is also a very popular area of research, and it comes in many forms. We're going to highlight two areas dysregulated sleep and dysregulated eating rhythms. Again, we're sharing this information with you not so that you memorize it, but in order to encourage you to use a wide angle lens. Let's start with stress in general. Number one, stress can dysregulate appetite and digestion. Short-term stress, as with severe and acute trauma, can shut down appetite through corticotropin-releasing hormone or CRH released by the hypothalamus, as well as the hormone epinephrine, otherwise known as adrenaline released by the adrenals. This makes sense as short-term stress is often associated with the fight or flight response. The body can't focus on things like eating and digestion when it's in protection and survival mode. Long-term stress is another story. Now the sympathetic nervous system is one major component of the stress response. Short-term, it initiates fight or flight, but when it's constantly on, it can alter reward pathways in the brain. Cortisol is a steroid hormone, also known as a glucocorticoid produced by the adrenal glands. It's known as the stress hormone. Under chronic stress, cortisol kicks in and increases appetite. However, digestion isn't a priority because the body is under too much stress all the time. The body perceives a threat and it can't differentiate whether you're being chased by a bear or if you just had an argument with your friend. High cortisol reactors, people who experience a higher cortisol spike in response to stress tend to snack more than low reactors. So we might eat when we're not physically hungry to help cope with stress, but our stressed out systems can't efficiently metabolize that food. As a result, appetite gets all out of whack, which can perpetuate harmful eating and stress cycles. Number two, stress can increase desire for pleasurable and palatable foods. Imagine you're having a long stressful day. It drags on and on and nothing seems to go your way. You're tired and you're frustrated. What are you more likely to reach for? Broccoli? Brownies? Again, there's a psychological self-medicating factor that motivates cravings for foods that both taste good and bring us pleasure. And over time, chronic stress can perpetuate emotional eating habits and cycles. There's also the factor of food associations, or the desire to recreate pleasurable past experiences through food, like baking with a family member, or enjoying the same popcorn and candy that we ate at movie theaters as children. To further complicate this web, those processed foods that we so often stress each are designed in labs for the perfect bliss point with an excellent balance of salt, sugar, and fat that keeps us craving and consuming more. They're literally engineered to make us overeat them. However, cortisol can also play a role. First of all, it mobilizes sugar so that the brain and muscles can be ready for fight or flight. This happens when we feel anxiously stressed, but also when we feel fatigued and fuzzy, and that explains why we might reach for sugar to pep us up. However, this raises blood sugar only briefly before that well-known sugar crash. You crash because your brain suddenly feels deprived of glucose, leaving you lightheaded, jittery, and in need of food, preferably sugar as soon as possible. So you reach for the sweet stuff. Going back to those high cortisol reactors, they tend to reach for foods higher in fat and sugar. Why is that? One reason is that cortisol stimulates a neurochemical called neuropeptide Y or NPY which acts on the brain to stimulate eating, in particular, eating carbohydrates. Together, cortisol and NPY can motivate cravings for and overeating of carbohydrates. As it turns out, if you start the day stressed and therefore turn on NPY in the morning, it might stay on all day. In addition, stress-induced boosts of NPY can stimulate the growth of abdominal fat. Add to this, the fact that cortisol tells the body to store fat and break down muscle for energy and you have one more vicious cycle. To recap so far, stress dysregulates appetite and digestion, and it can increase desire for certain foods, partly due to a mix of biochemical reactions in the body. It also makes the body more efficient at storing fat, which may contribute to further feelings of stress, depression, and feeling conflicted over your food choices. To further explore this, I'm going to highlight several body stressors. These are biological cycles or rhythms that can influence emotional eating. After all, the body functions on routines and disrupting its natural rhythms can wreak havoc on eating habits among other things. The first rhythm is sleep. Did you know that getting just six hours of sleep a night can increase your risk of obesity by 23%. Getting only five hours and that risk bumps up to 50%, and 73% with four hours of sleep. This seems to hold true for children as well as adults. We know that dysregulated sleep can act as a chronic stressor. This is a huge area of research, and science is still trying to figure it out. But here's some evidence so far. I'll keep it simple because, of course, it's a complicated web. Number one, lack of sleep increases appetite. Do you ever feel hungrier when you don't get enough sleep? It's not just you, two hormones leptin and ghrelin seem to play important roles in this as does insulin. Insulin is a hormone produced by the pancreas that regulates blood sugar levels. Basically, when you eat food, your body digests it and turns it into glucose so the body can use it for fuel. Insulin clears the glucose from the bloodstream by signaling cells to absorb it. We'll explore insulin later on. Leptin and ghrelin have a rather teeter-totter relationship. Leptin produced by fat cells in response to insulin is known as the satiety hormone. It suppresses appetite by signaling fullness. Ghrelin secreted by the digestive tract is the fast acting hunger hormone. It stops insulin release and signals hunger when the stomach is empty, and it stops when the stomach is full. Your stomach growling means ghrelin is high. And as it turns out, continually fighting cravings can be associated with elevated ghrelin levels. Normally, leptin remains low during the day and rises during sleep, while ghrelin does the opposite. However, a lack of sleep has the same effect of stress. It decreases leptin significantly during the day and increases ghrelin during the night. What does this mean? It usually means that we eat more during the day because our body doesn't feel full. We also might store fat more easily. Finally, losing the final REM cycle of sleep, which happens around six hours in might increase appetite. Again, science is still trying to figure this all out. But all of this research connects lack of sleep with a larger appetite, and it can help explain why you might wake up feeling hungrier than usual after a late night out. Number two, lack of sleep increases cravings for high-calorie, simple carbohydrate foods. Why? Because your body is wise and it wants energy when it's tired. This is why it feels more tempting to eat donuts at a morning meeting after a night of poor sleep. From a biological standpoint, your insulin doesn't respond as much to blood sugar. In other words, blood sugar remains higher than normal because insulin can't clear it out, which simulates cravings. This is what's known as insulin resistance, and it can lead to visceral fat build up aka that stubborn fat that's hard to lose. And what are the possible results of that? Weight gain, obesity, diabetes, you get the idea. Number three, circadian rhythms influence metabolic processes. Your body's circadian rhythms are biological clocks that generally follow a 24-hour cycle based on light. You might have heard of them if you've researched sleep cycles. They help explain why you might feel more refreshed in the morning if you wake up in the right part of your sleep cycle, while other mornings feel more challenging. When it comes to the science of eating, one interesting area of study is night shift workers. Many studies find a connection between night shifts and higher body fat percentage. In fact, these workers might be more likely to gain weight, even if they eat the same foods as people who don't work night shifts. If you think about it, night shifts work against our biological clocks. As a result, the body might not burn calories as efficiently. This relates to the second rhythm we'll highlight today, eating rhythms. In other words, when you eat might be just as important as what you eat. This is because different neurochemicals associated with appetite are different at different times of the day. Therefore, eating patterns that disrupts this natural rhythm can essentially stress the system. For example, skipping breakfast might slow metabolism. Not only does it encourage overeating later in the day, but it also goes against circadian rhythms. In the morning, blood sugar is low because the body has been fasting all night. Therefore, the body wants to break the fast by eating. Remember how NPY motivates eating, specifically carbs? NPY is normally higher in the morning, so skipping meals can increase NPY later on, which means bring on the carb feast. Skipping breakfast also motivates fat storage at the expense of muscle building. In short, the body has a system and messing with it can lead to short and long-term metabolic damage. For this reason, you might want to incorporate this into your coaching. For example, with clients who don't eat much all day because they're going out for big dinner that night. Eating late at night can also strain digestion. Going back to those circadian rhythms, we seem to burn calories less efficiently at night. The energy we expend digesting called diet-induced thermogenesis is lower at 8:00pm than it is at 8:00am. Why? Because sleep is a time to rest and rebuild. If we eat a lot right before bed, our body spend more time digesting and less time rebuilding and detoxing. I've experienced this myself in a rather powerful way. Once in a while, I eat a huge meal before bed, and sometimes, I wake up feeling hot. It's true. I consider it my body's way of saying, don't do that. Leptin and ghrelin also play a role here. Ghrelin tends to peak depending on your heaviest meal. Now this doesn't mean that you should tell your clients to never eat at night. It simply means that their digestion will be less efficient and effective which can lead to things like weight gain and insulin sensitivity in the long term. Awareness and striking a happy medium are key as is bio-individuality. A number of factors from eating habits to genetics and our body's natural set points can influence how our bodies respond to different ways of eating. However, if your clients are frustrated and feel stuck, this is yet one more area to explore. Eating rhythm habits can be very challenging to change. A habit of eating a lot at night sets you up for the same cycle the next day. You're not hungry in the morning, so you skip breakfast. Or perhaps, you don't get as much sleep because you're up late eating or because your body is busy digesting instead of resting, and you end up chowing down on this big portions of carbs that you crave because you're sleep deprived. Also, culture plays a role as it can be difficult to go against cultural norms. For instance, eating big meals in the evening is common in the US as well as many other places. When we eat can affect us not only physically, but also emotionally. Disrupted rhythms can promote moodiness, irritability, and cognitive fuzziness in addition to lower energy and everything else we've discussed. Do you see all the factors at play? Can you see how all of this might connect with emotional eating? Okay, let's end with a recap of the key points. Stress can dysregulate appetite and digestion, and it can increase desire for comfort foods on a biological as well as on a psychological level. Disrupting rhythms like sleep and eating which have to do with biological body clocks called circadian rhythms essentially stress the body. Things like sleep deprivation and eating most of your calories at night can also dysregulate appetite and metabolic processes like digestion, as well as increase cravings for high calorie, rich carbohydrate foods. These are hard habits to break. Emotional eating includes disconnecting from real hunger and stress throws appetite for a loop further exacerbating the challenge. What can you do as a Health Coach? Here's the bottom line. Start by focusing on stressing less and sleeping more. Otherwise, biology works against you, even with all of your efforts. Support clients by helping them work with versus against biology. Take both primary and secondary food habits into account. For example, you might help them develop strategies around eating and self-care on days when they're running low on sleep. And encourage clients to pay attention to their personal eating cycles. Okay, we're done. Time to try applying this material yourself. We've included an exercise handout called Finding Your Rhythm, so be sure to check that out. For now, think about your sleep and eating habits where might you make some small adjustments that support health. Share with your course mates in the Facebook group so we can continue encouraging each other. That's all for now. See you soon.