Glucose Metabolism: What is it and Why Does it Matter?
In your quest to support your health through better nutrition, you may have come to the decision that sugar should be avoided at all costs. Or you may just be tired of hearing that you should avoid it. However, sugar isn’t an inherently bad thing. Often it is as much about timing and what you are eating with your sugar that really matters. Let’s look at what happens in your body when you consume sugar, a process called glucose metabolism.
What is glucose metabolism?
Glucose is a simple sugar that provides our body with energy. Metabolism is the process your body undergoes to convert what you eat and drink into energy.
Glucose metabolism, then, is the process of our body breaking down carbohydrates that we eat into simple sugars, including glucose, and then how our body absorbs that glucose into our blood and converts it to energy or stores its energy to use later. In this post, we are only getting into the first parts of that process that involves glucose absorption into our bloodstream. Glucose comes from so much of what we eat. Generally, the sources can be divided into:
Natural sugars: the fructose in fruit and lactose in milk and the glucose in every whole food that contains carbohydrates
Added sugars: sugars added to food either in manufacturing or by you in cooking or preparing food/drinks like brown sugar and honey
Glucose metabolism pulls glucose from both simple sugars and complex sugars. This process takes the complex carbohydrates that we consume– like oatmeal, brown rice, and potatoes– and breaks them down into simple sugars that then turn into glucose.
When glucose is absorbed from your gut into your blood, we talk about the resulting levels of glucose in your blood as blood sugar. By the way, your body stores glucose, so you can also raise your blood sugar by doing things that release those stores like exercising or doing something stressful. But that’s a topic for another day.
Glucose metabolism comes down to this: What does your body do when you eat sugar? I’ve previously written a much more detailed description here, but in this post, I want to hit the highlights about why it matters.
What Does Your Body Do When You Eat Sugar?
When you consume sugar, how does your body process it?
Your body begins to break down the simple and complex carbohydrates and turns them into glucose.
The glucose is absorbed into your bloodstream through your small intestine’s lining.
Your blood sugar increases, so your insulin spikes to regulate it and bring it back down.
The insulin signals your body’s cells to absorb the glucose in your bloodstream and use it for energy.
The natural sugars found in fruit are accompanied by fiber and other nutrients, which slow your body’s absorption of them and prevent a sugar crash. This isn’t the case for sugar in fruit juice or added sugars– which are much more concentrated– so they are absorbed into your blood quickly, spiking your glucose. As soon as you consume this sugar, your brain experiences a surge of dopamine and serotonin (this is why we LOVE sugar so much). Because of its concentrated form, your body processes the added sugars extremely quickly, pouring insulin into your blood to get rid of it. Often the insulin overshoots, and you get rid of too much sugar, resulting in a sugar crash a couple of hours after you’ve eaten.
A Deeper Dive into Insulin
Insulin and glucose go hand in hand. While we think of insulin, we typically associate it with diabetes; a quick Google search on insulin results in almost all diabetes-related results. However, it’s a naturally occurring hormone found in all of our bodies. Produced by the pancreas, insulin allows the glucose in your blood to enter your cells in order to help your body turn sugar into energy.
Insulin regulates our blood sugar levels. When someone’s body is unable to use insulin properly or doesn’t produce enough insulin, the result is that the person develops diabetes.
Now, let’s be clear– eating too much sugar doesn’t mean you’re absolutely going to develop diabetes, but it is a contributing factor to developing type 2 diabetes. This chronic disease occurs when your body becomes resistant to insulin, requiring your pancreas to produce more insulin, until it just can’t keep up with the increased insulin needs.
How Does High Blood Glucose Impact Our Body?
The effect that sugar has on your body has a lot to do with what you eat with that sugar. A cookie by itself in the middle of the afternoon will likely send your blood sugar through the roof. But eat that same cookie right after a steak dinner with a glass of wine, and you might not spike your glucose at all. This is because adding in all that protein and fat balances out the surge of sugar and slows absorption. Being conscious about what you eat with sugar can go a long way in helping you to better manage your blood glucose levels.
Regular periods of hyperglycemia (high blood glucose) can impact nearly every part of your body–
Your liver is in charge of pulling that extra glucose out of your blood as quickly as possible. But it runs out of things to do with it. So it turns a lot of that glucose into fat and then stores the fat, which can result in non-alcoholic fatty liver disease. The liver can also make cholesterol with all that extra glucose—way more cholesterol than you need.
Your brain experiences cognitive deficiencies when you repeatedly experience hyperglycemia.
Your immune system is altered, promoting chronic inflammation.
Your arteries stiffen, which increases your risk of a stroke or heart attack.
Your blood vessels, nerves, tissues, and organs are damaged by hyperglycemia that’s untreated for long periods of time. Damaged blood vessels may increase the risk of a stroke or heart attack, and damage to your nerves can affect your eyes and kidney.
Your cells can eventually develop a resistance to insulin. Insulin resistance is a precursor to diabetes.
That short-term feel-good sugar rush to the brain can have long-lasting consequences for your health.
Sugar crashes
In addition to the strain on your body, you have to deal with the short-term annoyance of sugar crashes.
Have you ever been starving mid afternoon and grabbed a piece of fruit to tide you over for dinner and end up hungrier than ever? That’s because the glucose in the fruit spiked your blood sugar and then you came crashing down. Adding peanut butter to the apple or grabbing a piece of cheese would slow that response and is more likely to meet your goal of staying satiated until dinner.
Oftentimes if you find yourself reaching for caffeine mid-afternoon to stay awake after your lunch, it is because that sandwich or whatever you ate sent your blood sugar way up and crashing down. This can lead to you naturally craving more carbs to try to level out your sugar again.
Glucose Metabolism + Your Health
You can learn more about added sugar in this blog, but to make a long story short, it’s almost impossible– and not really necessary– to completely eliminate sugar from your diet. The key, like most things, is consuming it in moderation and in combination with fibers, fats, and proteins to keep your blood sugar more balanced.
I love talking with people about how they can make small tweaks to their dietary patterns to help stabilize their blood sugar to avoid the ups and downs. If you are feeling afternoon sluggishness, constantly leaning on snacks to get you through the afternoon, or are just interested in understanding blood sugar for your long-term health, let’s talk!
