Blood sugar affects stress, sleep and attention span
Updated: 7/18/2024
I’ve always known… in theory… dysregulated blood sugar would negatively impact our stress levels, sleep, and ability to learn. But over the years as I’ve helped people tighten up their blood sugar, I’ve seen some pretty dramatic improvement in their sleep and focus.
How does stress affect hormones?
Cortisol is a stress hormone… and it’s a good one! In the morning, you should have a nice burst of cortisol to get you up and moving. Cortisol levels gradually wane as the day goes on; so you are very low in the evening, allowing you to produce melatonin and sleep.
Cortisol is your “can-do” hormone. Have you ever had one of those days where you are just going and going, putting out fires all day long, and you sort of get a second wind and feel like… while you should be on your knees, you’re able to push through? That’s cortisol. It helps you rise to the occasion or pull an all-nighter. It keeps you going and going and going. Great when you have work to do. Not so great when you need to sleep.
Another stress hormone is adrenaline (epinephrine). This is your “fight-or-flight” hormone, which raises your heart rate.
Sympathetic vs Parasympathetic
Our autonomic nervous system (the one that ticks along in the background regulating our digestion, heart rate, breathing, etc) has 2 modes: sympathetic and parasympathetic. The parasympathetic is our “rest, digest and have sex” mode. That’s where we want to be most of the time to digest our food, make babies and feel good. But when we produce stress hormones like cortisol or adrenaline, it shifts our body into the sympathetic state. When that happens, it shuts down our digestion (to a certain degree) and redirects the blood to the muscles and brain so we can think, fight or run our way out of danger.
This is an oversimplistic view of it, but in a nutshell know this: If you are living in a sympathetic-dominant mode 90% of the time, your digestion will be impaired, cortisol levels will be dysregulated, and you might have lower melatonin production and impaired sleep.
How does blood sugar affect cortisol and stress?
Where does blood sugar fit into this? When you get low blood sugar, it causes adrenaline surges. You know that “hangry” feeling? You’re probably experiencing a bit of an adrenaline surge.
Low blood sugar is typically caused by eating foods/beverages that spike your blood sugar too high, and your body rebounds with low blood sugar. Your body reads this as stress. And if you have enough stress later in the day, you’re going to have higher afternoon/evening cortisol.
Your blood sugar doesn’t even have to go into clinical hypoglycemia, which is below 70mg/dl (or below 3.9mmol/L). For many, just that rapid descent can lead to these symptoms. We see this often when monitoring on a continuous glucose monitor. Their symptoms occur while blood sugar is dropping too quickly.
Since so much of what we eat is refined carbohydrates, has lots of added sugar, and would be called “high glycemic”, it means this yo-yo blood sugar is very common. In fact, nearly everyone I put on a continuous glucose monitor (CGM) is a bit of a hot mess for the first few weeks until they learn how to eat to suit their body.
Get to the root of the problem
Even 2 weeks using a continuous glucose monitor (CGM) can help you connect the dots. Grab a free guide to learn more and get a prescription from your doc… even if you don’t have diabetes!
Can diet cause sleep problems?
The short answer to this is, “Yes.”
Dysregulated blood sugar can cause high cortisol and high evening cortisol can keep you up at night.
You know those nights where you are overtired and all you want is to sleep, but you can’t? That “tired and wired” feeling is high cortisol keeping you awake.
It’s brutal, but it’s a reality the nights we MOST need to sleep and recover are the nights where we can have the hardest time sleeping. Let’s uncover some of the causes of this so we can find solutions.
The most common dietary cause that I see in my practice is the chronic yo-yo blood sugar. Every time your blood sugar goes throught that cycle of too high followed by too low (or rapid drop), it adds to your stress bucket. Life is already full of challenges that are out of your control. Food is something you can control.
Another issue is eating late. Because our digestion and circadian rhythms are so intertwined, they can affect each other. When you eat late, it tells your body that it’s still daytime and gets you off your sleep cycle. We have found that people tend to sleep better when they stop eating 2-3 hours prior to their bedtime.
Elevated blood sugar levels also cause you to urinate more frequently. If you eat a meal that takes your blood glucose high at night, it’s going to make you get up and pee more frequently. For many of us, that’s the #1 cause of nighttime waking!
Overeating in the evening, however, is extremely common and challenging to overcome. I find a lot of my clients overeat at night and we have linked it to high stress and not eating ENOUGH during the daytime. Enduring all that hunger and stress all day raises cortisol. And elevated cortisol will increase cravings for hyper-palatable food (pizza, cheeseburgers, fries, ice cream, cookies, etc). Also… our bodies might not receive enough nourishment! In any case, when we don’t eat enough during the day, we tend to overcompensate in the evening and that impairs our sleep.
How do you reduce cortisol so you can sleep?
Just reduce your stress!
Just kidding. I know from experience how hard this is to do. But I have some very actionable advice for you.
From a dietary perspective, pulling your evening meal back and eating less at night can really help. But most of the time, you can’t pull it back without addressing the cause of late eating.
Front-loading the day with protein and meals that nourish without spiking blood sugar will help to keep stress levels AND blood sugar levels more even. Then when dinner time rolls around, you’re not famished and your overeating triggers will have lessened.
Chronic undereating during the most active part of your day is another problem I see. This has become more problematic as intermittent fasting gains popularity. Many folks I see will live on caffeine until 11 or 12, then start their eating window with lunch. While not inherently bad, I see this causing 2 problems. One, they are asking a lot of their bodies during this time and not fueling it. This seems to add more stress to the system and (here’s where I’m speculating) tells the body there aren’t sufficient calories available so it drops metabolic rate. But what I definitely see is that either people can’t hit their protein targets in a narrowed eating window, or the prolonged morning fast leads to overeating later on.
One of the biggest surprises for me when I run my “Hack Your Blood Sugar Using a CGM” group program is how many people report better sleep by about week 3. I can’t say for sure what the reason is, but my theory is a reduction in stress hormones from eating more regularly in a way that keeps blood sugar stable throughout the day. They are almost all increasing protein and eating more in the morning and less in the evening.
There are plenty of other things we could talk about in terms of reducing stress. But if your blood sugar is a hot mess, that’s the place to start. The way to even out your blood sugar is to first see what’s going on and what’s causing the trouble.
I tend to recommend using a continuous glucose monitor to measure your blood sugar, for even 2-4 weeks. They can be obtained for about $40/2-week period and gives you a look under the hood so to speak. The reasons I prefer this method over blanket dietary recommendations is this.
Everyone reacts to food differently.
Poor sleep can be a root cause of dysregulated blood sugar.
Non-dietary stress can be the cause.
Also, once we find out that blood sugar is a bit of a problem, the solution can be just as personalized. A person doesn’t have to do ALL the things (sleep study, exercise more, go to bed earlier, cut carbs, intermittent fasting, etc). They need to do what works for them. Using a CGM for a few months can assist in learning what methods deliver the desired results.
While I like the tech companies out there providing AI learning with a CGM, you pay a lot of money for months and months of CGM use/data. But if you get the right support, you only need to use one for 4 weeks.
Does diet affect learning?
Absolutely. But unfortunately, unhealthy food for children is practically screaming at us from the supermarket shelves.
Brain fog is one of the classic symptoms of dysregulated blood sugar and prediabetes. Adults know what I’m talking about, but often our kids don’t know how to tell us. Brain fog can be a sign of high levels of inflammation in the body and we find this is common with insulin resistance and poor blood sugar control. It’s not the only cause of brain fog and inflammation! But it’s usually one of the factors and the easiest one to address.
The yo-yo blood sugar also hits kids hard. When they bottom out, and their body is screaming for more carbs to get their blood sugar up, it’s almost impossible to concentrate on anything else. They are literally in survival mode and math will take a back seat every single time.
Sleepy after lunch? When blood sugar is high, especially after a high-carbohydrate lunch, it tends to make us sleepy. Most of us have experienced that sleepy feeling in the afternoons when we have a hard time working or paying attention in class. It’s the reason we reach for the afternoon coffee (which keeps us up at night). Eating a protein-rich lunch that has a low to moderate amount of low-glycemic starchy foods followed by a walk can be the best way to ensure better focus for your afternoon tasks.
Need some lunch inspiration?
This free guide can help you AND inspire your kids to pack their own balanced lunch.
Does a poor diet cause ADHD?
As I describe in this YouTube video, when we eat sugary foods, it tends to create a blood sugar rollercoaster. It spikes our blood sugar, then causes a crash into low blood sugar. When we are low, we secrete stress hormones like adrenaline and get hangry and agitated. This also impairs concentration and amplifies anxiety and ADHD.
What’s the solution?
The solution is multifactorial. But strictly from a food perspective, it usually starts with breakfast and lunch. You know how they always say that breakfast is the most important meal of the day? That’s because your first meal really sets the tone for the rest of the day. If you eat a sugary breakfast that spikes your blood sugar, it not only makes you feel poorly then, it can cause you to have poor glucose control at your NEXT meal too. The first thing I address with my clients is their breakfast and what they add to their morning coffee. It sets the tone for the rest of their day and makes it all that much easier.
Lunch is the next part. I personally find when I don’t have lunch planned, I wait until I’m so hungry that I end up grabbing the most convenient thing that satisfies my craving. And that’s usually not food that will help me concentrate. Because so many of us… and certainly school-aged children… eat lunch away from home, planning and packing our meals becomes very important. This is a task that many dread, but finding a system that makes balanced protein-rich, nutritious lunches convenient will pay off for better energy and focus in the afternoons.
Tips for the neurodivergent crowd
Hyperfocus
If you or your child has ADHD, then you may have been gifted with the ability to hyperfocus. It’s brilliant for banging out a project or learning at light speed. But not so great when it causes you to skip meals and forget to drink water.
If this is you, setting timers and pre-making your lunch/snacks in such a way that you can bring them to your workspace and eat while working. I know it’s not ideal, but we don’t need ideal. We need good enough. Try making a smoothie, dishing up some cottage cheese, some assortment of good protein sources
For most adults and teens, I recommend 20-30g of protein per meal. When this gets challenging, I often recommend using protein smoothies to fill the gap. I also like to be sure there are some healthy fats to help you feel full along with some vegetables or high-fiber fruit. Water is a frequently overlooked part of lunch. When we get busy, we tend to forget to drink water and poor hydration can make us tired AND more hungry.
Overwhelm and the See-Food Diet
We all get overwhelmed with decision making and having to answer questions. ND folks seem to be especially prone to this. That’s why the See-Food diet works. Instead of asking a child what they want or if they even want to eat, try putting a plate of simple foods in front of them. “I made some things in case you feel like eating.” No pressure, no questions. This is the culinary version of declarative language. You can do this for yourself too. Putting it together ahead of time or ordering your lunches ahead of time (for the whole week) to be delivered and setting a timer to eat it means you don’t have to make more decidions. Food appears, you see it, you eat it.
Best order to eat food for blood sugar
This is a system that works great for my clients. When wearing a continuous glucose monitor, we can see how well this works. If we eat a high carbohydrate food (like bread, potatoes, rice) on an empty stomach, it spikes our blood sugar. But if we eat protein first, it blunts the spike giving us more sustained energy and better blood sugar control. Eating some fiber from vegetables (like a salad) improves this even more. So we’ve created the order of eating…
Need to get a handle on your blood sugar? Want to make it… fun?
Consider taking part in my 4-week group program. We use continuous glucose monitors (CGM) to guide us in created a highly individualized strategy for you to get your blood sugar (and insulin levels) dialed in to reduce stress, improve sleep, improve focus and of course, reduce your risk of diabetes and other chronic diseases. The CGM gives us 24/7 real-time data on how our food affects our bodies. It really “gamifies” the process. Learn more about it here.