Here’s Why a Sugar Crash Slows You Down — And How to Boost Your Energy

Although sugar may give you a boost, the surge is only temporary.
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It's 3 p.m. and your energy feels drained. That's when you reach into the office candy bowl to pull out a handful of chocolate. While it may give you a boost, the surge is only temporary, as you soon feel more fatigued, even sleepy. You may be experiencing the effects of a sugar crash.


Read more:How to Quickly Reverse a Sugar Crash

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Science Behind a Sugar Crash

When you eat foods that contain added sugar, those sugars "quickly absorb into the bloodstream and cause a spike in your blood sugar level, also known as your blood glucose level," says Alicia Galvin, RD, a registered dietitian in Dallas. Added sugars include ingredients like honey, maple syrup and coconut sugar. These "natural" sugars aren't necessarily better for you. Metabolically, they affect blood glucose in a similar way to other sugars, like cane sugar, she says.

As a result, that blood sugar spike might make you feel more energetic, but it's unlikely that vigor to tackle your to-do list will last long. "Since our body likes to have [blood sugar] levels balanced, this quick increase in blood sugar causes a surge of insulin to be produced to try to quickly bring the blood levels back in balance," explains Galvin. The fast dip in blood sugar is also known as a sugar crash.

What Happens During Sugar Crashes?

It's a common experience to feel that a sugar crash makes you sleepy. Some other symptoms you may experience, says Galvin, include weakness, fatigue, shakiness, nausea, irritability or headaches. You might also notice that you're hungry — and crave the very foods that will quickly spike your blood sugar once again. That's sometimes referred to as a blood sugar roller coaster, she says.


The problem is that, for some people, blood sugar that's either too high or low can be dangerous.

Foods to Regulate Blood Sugar

The foods that can take you for a ride on that blood sugar roller coaster include added sugars — both refined sugars like corn syrup or cane sugar and "natural" options like honey and maple syrup — in foods like candy, cookies and soda, says Galvin.


Some traditionally healthy foods may also be packed with the sweet stuff, like packaged instant oatmeal, granola bars and cereals. Refined carbohydrates should be another red flag, and that includes foods made with white, refined flour (white bread, packaged snacks and crackers).


On the other hand, there are smart ways to prevent blood sugar spikes — and subsequent dips. "The best way to keep blood glucose levels stable and in balance is to eat whole foods, focusing on fiber, protein and fat. When you include these as part of a meal, they work to regulate the rise in blood sugar, so it does not spike and then drop," says Galvin. She suggests a few swaps for blood sugar management:


  • Instead of chips or crackers, go for roasted, salted nuts or seeds.
  • Instead of flavored yogurt, go for plain, full-fat yogurt with nuts and blueberries.

Issues to Watch Out For

As your blood glucose level increases, insulin rises along with it. Insulin is a hormone that drives glucose into your body's cells to provide energy, according to the Endocrine Society.


Over time, however, "high levels of blood sugar circulating in the blood cause an increased demand on the pancreas to make insulin, and eventually the cells become resistant to the insulin," explains Galvin. This can contribute to insulin resistance and prediabetes, notes the National Institute of Diabetes and Digestive and Kidney Diseases.

If you're experiencing frequent blood sugar crash issues, ask your doctor if you should get a blood test to check your fasting insulin, blood glucose and fasting hemoglobin A1C, says Galvin. "If they are elevated, that may indicate you'll want to make some dietary changes," she says.


Exercise will also help lower your blood sugar by using blood glucose for energy, and long-term it makes your body more sensitive to insulin. So don't forget to get moving.

Read more:10 Foods You Don't Realize Are Packed With Sugar




Is this an emergency? If you are experiencing serious medical symptoms, please see the National Library of Medicine’s list of signs you need emergency medical attention or call 911.

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