Blood Sugar Balance  |  Personalized Nutrition  |  Stress Reduction

Stress And Blood Sugar: What You Need To Know

by: Jamie Foti MS, RDN, IFNCP  |  November 9, 2023

We say it all the time: there are many things that raise blood sugar outside of just what you eat. And while it’s very important to balance your plates to support optimal blood sugar, just as important is monitoring your stress. Stress has the ability to increase your blood sugar because of the stress hormone, cortisol.

Cortisol, the “fight or flight” hormone, prepares your body to run at a moment’s notice. It helps to break down stored forms of glucose so they can be released into the bloodstream, and helps to keep those blood glucose levels high so you have easy access to this fuel.

While our stressors may no longer be running away from tigers, our bodies still respond in the same way, increasing the available glucose to prime our bodies for attack. That means that your body can’t tell the difference between those emails, calls from your kids’ school, or rush hour traffic and a tiger attack. 

Is Cortisol Bad?

It has a time and a place and can be very necessary in certain situations. The issue is when cortisol is elevated long term, since that doesn’t give your body the opportunity to return to baseline. Let’s break down stress into its two forms, short and long term.

Short-Term Stress

You can think of short-term stress as something acute that comes and goes fairly quickly, like giving an important presentation or doing a high intensity workout. In these moments, cortisol will increase to support you in performing well. You might notice increased focus or speed as you begin these stressful tasks, but your body is able to recover once the event is over. If you’re wearing a continuous glucose monitor (CGM) during these events, you may even notice your blood sugar spike. This is not a problem, as long as blood sugar comes back down. It is simply showing you how your body uses that cortisol molecule to make glucose more available during your time of need.

Long-Term Stress

The issue arises when you stack these short-term stressors back to back or adopt more chronic stressors such as a packed schedule, a high demand job, too much caffeine on a day-to-day basis, fasting for too long, infections or gut dysbiosis, or eating too low carb or low calorie. Even if you don’t feel the mental burden of these stressors, your body will physically feel the consequences. I see clients all the time who come to me claiming to have low stress, but live life meeting-to-meeting while attempting to intermittent fast and squeeze in high intensity workouts. Though there is a time and place for things like high intensity exercise or fasting, adding these on top of an already stressful life can cause cortisol dysregulation, which can then cause blood sugar dysregulation.


Can What I'm Eating Impact Cortisol Levels?

What can be the most confusing is that diets that are typically reported to help blood sugar balance can actually increase blood sugar as a result. These would be diets such as very low carb, intermittent fasting, or very low calorie diets. All of these diets require you to produce more cortisol so you can break down stored forms of glucose or to help convert other macromolecules into usable forms of energy. In the short-term, these diets may work, but when followed for too long, they can start to backfire. As cortisol rises, so does fasting blood sugar. This isn’t to say that some people won’t benefit from these kinds of diet interventions, especially in the short-term, but it’s important to recognize when these interventions are hurting you.

A clear clinical picture that these diets are no longer helping you is if you are eating very “healthy” and low carb, yet your fasting blood sugar is very high. Along with this, you may even see high LDL cholesterol with normal HDL cholesterol and triglycerides, which is a sign of stress more than metabolic dysfunction. If you are seeing labs like this while eating low carb and you have a stressful lifestyle, it may be time to cut back on the stressors. This could mean adding in a meditation practice, adding in some more whole food carbs, reducing your fasting window, or reducing your exercise intensity. Overall, if you feel like you’re doing everything for your blood sugar and not seeing results, it’s time to look at stress!


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