Blood sugar spikes occur when your blood sugar rises and then falls sharply after you eat.
In the short term, they can cause lethargy and hunger. Over time, your body may not be able to lower blood sugar effectively, which can lead to type 2 diabetes.
Diabetes is a rising health problem. In fact, 29 million Americans have diabetes, and 25% of them don't even know they have it (1).
Blood sugar spikes can also cause your blood vessels to harden and narrow, which can lead to a heart attack or stroke.
This article looks at 12 simple things you can do to prevent blood sugar spikes.
Carbohydrates (carbs) are what cause blood sugar to rise.
When you eat carbs, they are broken down into simple sugars. Those sugars then enter the bloodstream.
As your blood sugar levels rise, your pancreas releases a hormone called insulin, which prompts your cells to absorb sugar from the blood. This causes your blood sugar levels to drop.
Summary: A low-carb diet can help prevent blood sugar spikes and aid weight loss. Counting carbs can also help.
Refined carbs, otherwise known as processed carbs, are sugars or refined grains.
Some common sources of refined carbs are table sugar, white bread, white rice, soda, candy, breakfast cereals and desserts.
Refined carbs have been stripped of almost all nutrients, vitamins, minerals and fiber.
Refined carbs are said to have a high glycemic index because they are very easily and quickly digested by the body. This leads to blood sugar spikes.
A large observational study of more than 91,000 women found that a diet high in high-glycemic-index carbs was associated with an increase in type 2 diabetes (10).
The spike in blood sugar and subsequent drop you may experience after eating high-glycemic-index foods can also promote hunger and can lead to overeating and weight gain (11).
The glycemic index of carbs varies. It's affected by a number of things, including ripeness, what else you eat and how the carbs are cooked or prepared.
Generally, whole-grain foods have a lower glycemic index, as do most fruits, non-starchy vegetables and legumes.
Summary: Refined carbs have almost no nutritional value and increase the risk of type 2 diabetes and weight gain.
The average American consumes 22 teaspoons (88 grams) of added sugar per day. That translates to around 350 calories (12).
While some of this is added as table sugar, most of it comes from processed and prepared foods, such as candy, cookies and sodas.
You have no nutritional need for added sugar like sucrose and high-fructose corn syrup. They are, in effect, just empty calories.
Your body breaks these simple sugars down very easily, causing an almost immediate spike in blood sugar.
Studies show that consuming sugars is associated with developing insulin resistance.
In 2016, the US Food and Drug Administration (FDA) changed the way foods have to be labeled in the US. Foods now have to display the amount of added sugars they contain in grams and as a percentage of the recommended daily maximum intake.
An alternative option to giving up sugar entirely is to replace it with natural sugar substitutes.
Summary: Sugar is effectively empty calories. It causes an immediate blood sugar spike and high intake is associated with insulin resistance.
At present, two out of three adults in the US are considered to be overweight or obese (15).
Being overweight or obese can make it more difficult for your body to use insulin and control blood sugar levels.
This can lead to blood sugar spikes and a corresponding higher risk of developing type 2 diabetes.Weight loss, on the other hand, has been shown to improve blood sugar control.
In one study, 35 obese people lost an average of 14.5 pounds (6.6 kg) over 12 weeks while they were on a diet of 1,600 calories a day. Their blood sugar dropped by an average of 14% (19).
In another study of people without diabetes, weight loss was found to decrease the incidence of developing type 2 diabetes by 58% (20).
Summary: Being overweight makes it difficult for your body to control blood sugar levels. Even losing a little weight can improve your blood sugar control.
Exercise helps control blood sugar spikes by increasing the sensitivity of your cells to the hormone insulin.
Exercise also causes muscle cells to absorb sugar from the blood, helping to lower blood sugar levels (21).
Both high-intensity and moderate-intensity exercise have been found to reduce blood sugar spikes.
One study found similar improvements in blood sugar control in 27 adults who carried out either medium- or high-intensity exercise (22).
Whether you exercise on an empty or full stomach could have an effect on blood sugar control.
One study found exercise performed before breakfast controlled blood sugar more effectively than exercise done after breakfast (23).
Increasing exercise also has the added benefit of helping with weight loss, a double whammy to combat blood sugar spikes.
Summary: Exercise increases insulin sensitivity and stimulates cells to remove sugar from the blood.
Fiber is made up of the parts of plant food that your body can't digest.
It is often divided into two groups: soluble and insoluble fiber.
Soluble fiber, in particular, can help control blood sugar spikes.
Fiber can also make you feel full, reducing your appetite and food intake (26).
Good sources of soluble fiber include:
- Some fruits, such as apples, oranges and blueberries
- Many vegetables
Summary: Fiber can slow the absorption of carbs and the release of sugar into the blood. It can also reduce appetite and food intake.
Not drinking enough water can lead to blood sugar spikes.
When you are dehydrated, your body produces a hormone called vasopressin. This encourages your kidneys to retain fluid and stop the body from flushing out excess sugar in your urine.
One study of 3,615 people found that those who drank at least 34 ounces (about 1 liter) of water a day were 21% less likely to develop high blood sugar than those who drank 16 ounces (473 ml) or less a day (28).
A long-term study on 4,742 people in Sweden found that, over 12.6 years, an increase of vasopressin in the blood was linked to an increase in insulin resistance and type 2 diabetes (30).
How much water you should drink is often up for discussion. Essentially, it depends on the individual.
Always make sure you drink as soon as you're thirsty and increase your water intake during hot weather or while exercising.
Stick to water rather than sugary juice or sodas, since the sugar content will lead to blood sugar spikes.
Summary: Dehydration negatively affects blood sugar control. Over time, it can lead to insulin resistance and type 2 diabetes.
Vinegar, particularly apple cider vinegar, has been found to have many health benefits.
One study found vinegar significantly reduced blood sugar in participants who had just consumed a meal containing 50 grams of carbs. The study also found that the stronger the vinegar, the lower the blood sugar (31).
Another study looked into the effect of vinegar on blood sugar after participants consumed carbs. It found that vinegar increased insulin sensitivity by between 19% and 34% (37).
The addition of vinegar can also lower the glycemic index of a food, which can help reduce blood sugar spikes.
A study in Japan found that adding pickled foods to rice decreased the glycemic index of the meal significantly (38).
Summary: Vinegar has been shown to increase insulin response and help control blood sugar when taken with carbs.
Studies show both chromium and magnesium can be effective in controlling blood sugar spikes.
Chromium is a mineral that you need in small amounts.
It is thought to enhance the action of insulin. This could help control blood sugar spikes by encouraging the cells to absorb sugar from the blood.
In one small study, 13 healthy men were given 75 grams of white bread with or without chromium added. The addition of chromium resulted in about a 20% reduction in blood sugar following the meal (39).
However, findings on chromium and blood sugar control are mixed. An analysis of 15 studies concluded that there was no effect of chromium on blood sugar control in healthy people (40).
Recommended dietary intakes for chromium can be found here. Rich food sources include broccoli, egg yolks, shellfish, tomatoes and Brazil nuts.
Magnesium is another mineral that has been linked to blood sugar control.
In one study of 48 people, half were given a 600-mg magnesium supplement along with lifestyle advice, while the other half were just given lifestyle advice. Insulin sensitivity increased in the group given magnesium supplements (41).
Another study investigated the combined effects of supplementing with chromium and magnesium on blood sugar. They found that a combination of the two increased insulin sensitivity more than either supplement alone (42).
Recommended dietary intakes for magnesium can be found here. Rich food sources include spinach, almonds, avocados, cashews and peanuts.
Summary: Chromium and magnesium may help increase insulin sensitivity. Evidence shows they may be more effective together.
Cinnamon and fenugreek have been used in alternative medicine for thousands of years. They have both been linked to blood sugar control.
The scientific evidence for the use of cinnamon in blood sugar control is mixed.
One of these studies followed 14 healthy people.
It found that eating 6 grams of cinnamon with 300 grams of rice pudding significantly reduced blood sugar spikes, compared to eating the pudding alone (45).
However, there are also studies that show cinnamon has no effect on blood sugar.
One review looked at 10 high-quality studies in a total of 577 people with diabetes. The review found no significant difference in blood sugar spikes after participants had taken cinnamon (47).
There are two types of cinnamon:
- Cassia: Can come from several different species of Cinnamomum trees. This is the type most commonly found in most supermarkets.
- Ceylon: Comes specifically from the Cinnamomum verum tree. It is more expensive, but may contain more antioxidants.
The European Food Safety Authority (EFSA) has set the tolerable daily intake of coumarin at 0.045 mg per pound of body weight (0.1mg/kg). This is around half a teaspoon (1 gram) of Cassia cinnamon for a 165-pound (75-kg) person (48).
One of the properties of fenugreek is that the seeds are high in soluble fiber.
This helps prevent blood sugar spikes by slowing down the digestion and absorption of carbs.
However, it appears that blood sugar levels may benefit from more than just the seeds.
In one study, 20 healthy people were given powdered fenugreek leaves mixed with water before they ate. The study found the fenugreek reduced their blood sugar levels after eating by 13.4%, compared to the placebo (49).
An analysis of 10 studies found that fenugreek significantly reduced blood sugar two hours after eating (50).
Fenugreek may help reduce blood sugar spikes. It can be added to food, but it does have quite a strong taste, so some people prefer to take it as a supplement.
Summary: Both cinnamon and fenugreek are relatively safe. They may have beneficial effects on your blood sugar if you take them with a meal that contains carbs.
One study looked at 116 people with type 2 diabetes who either received berberine or a placebo for three months. Berberine reduced blood sugar spikes after a meal by 25% (58).
However, another study found berberine caused side effects in some people, such as diarrhea, constipation and gas (59).
Although berberine appears to be fairly safe, speak to your doctor before taking it if you have any medical conditions or are taking any medication.
Summary: Berberine has minimal side effects and studies have shown it can reduce blood sugar spikes by 25% after you eat it.
If you really want to reduce your blood sugar spikes, you should also consider these lifestyle factors that can affect blood sugar.
Stress can negatively affect your health in a number of ways, causing headaches, increased blood pressure and anxiety.
It has also been shown to affect blood sugar. As stress levels go up, your body releases certain hormones. The effect is to release stored energy in the form of sugar into your bloodstream for the fight-or-flight response (60).
One study of 241 Italian workers found an increase in work-related stress was directly linked to an increase in blood sugar levels (61).
Both too little and too much sleep have been associated with poor blood sugar control.
A study in 4,870 adults with type 2 diabetes found those who slept for the longest or shortest durations had the poorest blood sugar control. The best control was found in those who slept between 6.5 and 7.4 hours a night (63).
Even having one or two bad nights can affect your blood sugar levels.
A study of nine healthy people showed that sleeping too little, or only for 4 hours, increased insulin resistance and blood sugar levels (64).
With sleep, quality is as important as quantity. A study found the deepest level of sleep (NREM) to be most important in terms of controlling blood sugar (65).
Alcoholic drinks often contain a lot of added sugar. This is particularly true for mixed drinks and cocktails, which can contain up to 30 grams of sugar per serving.
The sugar in alcoholic drinks will cause blood sugar spikes in the same way as added sugar in food. Most alcoholic drinks also have little or no nutritional value. As with added sugar, they are effectively empty calories.
Furthermore, over time, heavy drinking can decrease the effectiveness of insulin, which leads to high blood sugar and can eventually lead to type 2 diabetes (66).
However, studies show that moderate, controlled drinking can actually have a protective effect when it comes to blood sugar control and can also lower the risk of developing type 2 diabetes (67, 68, 69).
One study found that drinking moderate amounts of alcohol with meals may reduce blood sugar spikes by up to 37% (70).
Summary: Poor sleep, stress and high alcohol intake all negatively affect blood sugar. That's why it is important to consider lifestyle interventions as well as diet.
Simple dietary changes, such as sticking to a low-carb, high-fiber diet and avoiding added sugars and refined grains, can help you avoid blood sugar spikes.
Exercising regularly, maintaining a healthy weight and drinking plenty of water can also have added benefits to your health beyond helping to control your blood sugar.
That said, if you have any medical conditions or are on any medications, speak to your doctor before making any changes to your diet.
For most people, making these simple diet and lifestyle changes is a great way to lower your risk of developing insulin resistance or type 2 diabetes.