Key Takeaways

• If your blood sugar is on a constant rollercoaster of highs and lows, it can leave you exhausted, moody, and hungry throughout the day.
• The good news: You can stabilize your blood glucose with a few simple lifestyle changes.

Have you ever experienced a sugar crash?

Maybe you eat a big dessert or drink a soda with lunch. Your blood glucose spikes, and for about half an hour, you feel great—lots of energy, positive mood, and so on.

But before long, that sugar high runs out. Brain fog makes it hard to focus. Your energy takes a dip. You’re irritable and moody. Maybe you’re hit with food cravings even though you just ate.

If you’ve ever crashed after eating sugar or refined carbs, you know what it’s like to have unstable blood sugar levels.

Your blood glucose affects your:

• Brain function
• Mental focus
• Energy level
• Mood
• Hunger and food cravings
• Longevity
• Risk of disease

When you’re in good shape, your body can deal with the occasional spike in blood glucose. But if your blood sugar is on a constant rollercoaster of highs and lows—due to your diet, age, genetics, and other factors—it can leave you exhausted, moody, and hungry throughout the day. 

The good news: You can stabilize your blood glucose with a few simple lifestyle changes. In this article, you’ll learn about the benefits of stable blood glucose, as well as simple ways to keep your blood sugar steady throughout the day. 

4 Benefits of Stable Glucose

You usually hear about blood glucose in the context of diabetes.

But even if you aren’t diabetic, stabilizing your blood sugar is a powerful way to live longer, improve your mood and energy levels, and lose weight faster.

Here are four major benefits that come from keeping your blood sugar stable.

Stable Energy

Refined carbohydrates break down very easily in your body. They’re already so close to glucose that you barely need to digest them.

Refined carbs rush through the digestive process and go straight to your bloodstream. Sugar-rich blood circulates throughout your body and your cells can grab onto as much of it as they need.

However, high blood sugar can be a problem if it lasts too long. Your body knows that, so when it detects lots of glucose in your bloodstream, it releases insulin, a hormone that directs sugar out of your blood and into your cells, and brings your blood glucose back down within a normal range.

This process works great for smaller blood sugar spikes. You eat some slow-digesting carbs, your blood sugar rises, you release a bit of insulin, and your blood sugar falls back to normal.

But if you feel lethargic after a carb-rich meal, your insulin response may be off. Many people don’t tolerate carbs well and have trouble releasing the right amount of insulin at the right time; instead, you put out more insulin than you need¹, and you release it late.

The result is low blood sugar, which can leave you tired and struggling to stay focused².

This yo-yo effect demonstrates how blood sugar swings mess with your energy levels. You go from an energy-rich high to an energy-poor low, instead of staying in the middle and enjoying stable, continuous energy throughout the day.

You see this energy crash in research on blood sugar and diet:

<ul role="list"><li>In a 2017 study, researchers put people on high-glycemic and low-glycemic diets for 28 days. People on high-glycemic diets—diets that cause swings in blood sugar—had significantly more depressive symptoms, mood swings, and fatigue³.</li><li>A 2019 research review found similar results: people experienced fatigue and decreased alertness⁴within an hour of eating refined carbs.</li></ul>

If you get sleepy and have trouble focusing after meals, consider cutting back on sugar and other high-glycemic foods. Doing so will stabilize your blood glucose and improve your energy.

Sustainable Weight Loss

Your brain contains special cells that sense your blood sugar levels and change your appetite accordingly⁵. If your blood glucose is low, your brain sends signals to make you eat more—but if your blood sugar stays stable, your brain tells your body that you’re full, reducing your hunger levels⁶.

In other words, swings in blood sugar can make you hungry, making you more likely to overeat⁷.

On top of that, high-glycemic foods, which disrupt your blood sugar levels most, are especially rewarding and can elicit strong food cravings. 

In a 2013 study, men ate either a low-glycemic or high-glycemic meal. The men who ate the high-glycemic meal had low blood sugar afterward, and they reported significantly more food cravings⁸.

There was another interesting finding: brain scans found that when the men ate high-glycemic food, the reward centers of their brains lit up about an hour after the meal, right when the participants’ cravings kicked in. 

Foods that spike your blood glucose are often highly rewarding. They activate the pleasure centers of your brain, which is great during the meal, but once that part of your brain goes dark, you’re left wanting more. That’s why more and more research suggests that high-glycemic foods play a role in food addiction⁹ and obesity¹⁰.

On the other hand, diets that keep blood sugar stable, like low-glycemic¹¹ or low-carb diets, actually decrease food cravings¹². Not surprisingly, they also work better¹³ for long-term weight loss¹⁴.

If you’re trying to lose weight but food cravings keep sabotaging you, prioritize stabilizing blood sugar to reach your fitness goals.

<p class="pro-tip"><strong>Learn more about </strong> <a href="/blog/blood-sugar-metabolic-health">blood sugar and metabolic health</a>.</p>

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Mental Clarity

Blood sugar affects your brain, too. Unstable blood sugar decreases alertness⁴ and increases mood swings³and depressive symptoms.

Spikes in blood sugar are also linked to subtle brain injuries¹⁵; a 2015 study found that poor blood sugar control links to decreased attention, lapses in memory, and loss of gray matter¹⁶ (a major component of your brain), even in young adults without diabetes.

More long-term, constantly yo-yoing blood sugar may contribute to dementia, especially Alzheimer’s. In fact, some researchers call Alzheimer’s “type 3 diabetes” because of the link between unstable blood sugar and brain degeneration¹⁷.

For reference, about 35% of Americans have poor blood sugar control without diabetes¹⁸, and about 84% of people with poor blood sugar control¹⁹ don’t realize that they have it.

By stabilizing your blood sugar, you can keep your brain strong, both short-term and long-term. 

Longevity

Stable blood sugar may stave off dementia and keep your brain healthy well into old age. But that’s not the only way that blood sugar affects longevity.

If you routinely spike your blood glucose over time, you can begin to develop insulin resistance. Basically your body, confused by the constant up-and-down in your blood sugar, begins misjudging how much insulin you need to keep your blood sugar stable.

Sometimes it releases too much insulin, other times it releases too little, and as time goes on, you lose your ability to stabilize your blood sugar.

Insulin resistance is a strong risk factor for many common age-related diseases, including type 2 diabetes²⁰, non-alcoholic fatty liver disease, heart attack²¹ and stroke, and obesity²².

Stable blood sugar keeps your body sensitive to insulin²³ and reduces your risk of disease, especially as you get older.

<p class="pro-tip">Read these tips on how to control blood sugar spikes after meals.</p>