How to Prevent Blood Sugar Spikes: Meal Sequencing and Smart Snacking

Do you ever feel anxious about your blood sugar levels because you suddenly feel sleepy or lethargic after a meal, even though your medical checkup results were normal? This article explains the mechanism behind glucose spikes, practical tips you can incorporate into your meals, snacks, and exercise, as well as how to keep a record of your physical condition.

What happens during a glucose spike?

A glucose spike refers to a state where blood sugar levels rise and fall rapidly after eating. Even if a medical checkup reports "no abnormalities," these sudden fluctuations may not be detected.

The mechanism behind sudden spikes and drops

The term "glucose spike" describes a state where blood sugar levels spike rapidly after a meal and then drop sharply. It is believed that eating only carbohydrate-rich foods after a long period of fasting tends to cause greater fluctuations in blood sugar. When having snacks, it is important to consider the overall balance of your diet rather than relying on specific foods. For more details on the relationship between snacking and blood sugar spikes, please refer to Are snacks the cause of glucose spikes? The right approach.

Changes that are difficult to capture with fasting blood glucose or HbA1c

Medical checkups often measure blood glucose levels while fasting or at a specific time after consuming glucose. According to the Ministry of Health, Labour and Welfare's classification, the venous plasma glucose level measured 2 hours after drinking 75g of glucose is categorized, for example, as under 140 mg/dL or over 200 mg/dL (Ministry of Health, Labour and Welfare). This value reflects a specific point in time—2 hours later. Sudden rises and falls that occur in shorter intervals, such as 30 minutes or an hour after a meal, may not be visible through this test alone. If you continue to feel intense drowsiness or lethargy after meals despite normal checkup results, it is a good idea to record these changes in your physical condition.

What adjustments can you make regarding eating order and drinks?

There are adjustments you can start today that don't require special foods or calorie counting simply by reviewing the order in which you eat and what you drink. We will introduce methods that involve small changes to your usual habits, such as switching from a rice bowl dish (donburi) to a set meal (teishoku) or replacing sugary drinks with water or unsweetened tea.

Eat vegetables and protein first

When eating a set meal, what is the first thing you reach for with your chopsticks? Eating salads or side dishes, followed by protein sources like grilled fish or rolled omelets, and saving the rice for last is known as "veggie-first" eating, and it is an effective way to suppress rapid rises in blood sugar after a meal. There is no need to increase the types or amounts of ingredients used. Even with a convenience store bento, you can achieve the same effect by eating the side dishes first instead of mixing the rice and toppings together. Whether you are dining out or eating a packed lunch, this is an easy habit to maintain because you only need to change the order without changing the menu itself.

Tips for switching from a rice bowl to a set meal

There may be days when your lunch break is short and you tend to choose meals that can be eaten quickly. Rice bowl dishes like oyakodon or beef bowls are difficult to eat in a specific order because the rice and toppings are combined. By choosing a set meal at the same restaurant instead, the rice, soup, main dish, and side dishes are served separately, making it easier to eat vegetables and protein first. Many restaurants offer set meals at a price that is almost the same, and because the number of items increases, you may even get an extra vegetable dish. When you are torn between a rice bowl and a set meal, try starting by choosing the set meal.

Replace sugary drinks with water or unsweetened tea

Canned coffee, sweetened soft drinks, and sports drinks contain sugar or high-fructose corn syrup. When you choose sugary drinks with your meals or during breaks, you are adding the sugar from the drink to the carbohydrates you get from your meal. By switching to drinks that contain no sugar, such as water, barley tea, or green tea, you can reduce this extra sugar intake. Vending machines and convenience store drink aisles are filled with unsweetened tea and black coffee. If you find yourself reaching for a sugary drink, try opting for an unsweetened product instead.

The relationship between coffee and blood sugar

You might find yourself reaching for a sweet cafe latte or syrup-filled coffee when you feel sleepy in the afternoon. Research findings on how coffee itself affects blood sugar levels are divided, so we cannot definitively state its effect here. What we can say for sure is that what you add to your coffee significantly changes the amount of carbohydrates per cup. If you drink unsweetened black coffee or an Americano, the carbohydrate content remains minimal, but a sweetened cafe latte or a Frappuccino with syrup contains more carbohydrates than it may look. When you crave something sweet, it's best to start by reviewing the amount of sugar or syrup you add to your coffee. However, post-meal drowsiness is not always caused by blood sugar levels. For tips on how to distinguish the causes if drowsiness and persistent lethargy continue, please refer to Is afternoon sleepiness due to blood sugar? How to distinguish causes and review your lunch.

When and how much light exercise should you do after a meal?

You might wonder whether it is better to sit down immediately after lunch or to walk around a bit first. Here, we introduce what research has shown regarding the timing and duration of exercise.

How does light exercise 15–30 minutes after a meal change blood sugar? (Findings from research)

In an experiment conducted by the Kyoto Women's University Home Economics Society targeting healthy young women, participants performed 10 minutes of light step exercise 15 or 30 minutes after starting a meal (Source: Kyoto Women's University Home Economics Society). This experiment showed that exercising 30 minutes after starting a meal resulted in lower blood sugar levels 45 minutes after the meal compared to those who did not exercise. Additionally, in cases where exercise was performed 15 or 30 minutes after the meal, the overall rise in blood sugar up to 60 minutes after the meal was smaller than in cases without exercise. Activities that take about 10 minutes, such as walking to the post office after lunch or walking around your office floor, can easily fit into this timing. On days when you can move around immediately after a meal, it is recommended to be conscious of moving your body lightly within 15–30 minutes rather than spending the time sitting still.

Considering exercise one hour after a meal as an option

There may be days when you have back-to-back meetings or cannot leave your seat immediately after a meal. The Ministry of Health, Labour and Welfare's e-Health Net states that for people with diabetes, exercising one hour after a meal is effective in improving post-meal hyperglycemia (Source: Ministry of Health, Labour and Welfare e-Health Net). Since this content is aimed at people with diabetes, it cannot necessarily be applied directly to everyone. However, it can serve as a guide for when to take a light walk about an hour after lunch on days when you cannot move right after eating. Don't give up just because you couldn't move 15–30 minutes later; even just standing up and walking an hour later is a better opportunity to move your body than staying seated.

How do skipping breakfast and snacking affect blood sugar?

Have you ever felt sleepier than usual after lunch on a day when you skipped breakfast? Let's look at how skipping meals and the timing or content of snacks relate to how blood sugar levels rise.

Skipping breakfast may affect blood sugar at the next meal

Many people are short on time in the morning and head to work after having only coffee. Skipping breakfast itself is not necessarily a problem, but it is said that after a long period of fasting, blood sugar levels may be more likely to spike during the next meal. If you eat your usual portion of a carbohydrate-rich dish like a rice bowl or pasta for lunch on a day you skipped breakfast, you might feel that your blood sugar levels are rising differently than usual. You don't necessarily have to eat three meals every single day, but on days when the interval between meals is extremely long, it is a good idea to make adjustments such as starting your next meal with vegetables or protein, or reviewing your portion sizes.

The results of snacking depend on "when and what"

When you get a bit hungry at 3:00 PM and decide to have a snack, your choice affects your body. Consuming a lot of sugary sweet bread or juice at once while hungry makes blood sugar levels more likely to rise rapidly. The timing of your snack is also important; if you have a large snack right before dinner, the total carbohydrate intake combined with your dinner will increase. It is recommended to use snacks to prevent "overeating at your next meal because you were too hungry," while deciding on the portion and the time of day in advance.

Can recording your physical condition be useful for medical consultations?

If you keep a note of days when you feel sleepy or lethargic after a meal, you may start to see patterns regarding when and what you ate. However, this record only indicates trends in your physical condition, not blood sugar levels themselves.

Post-meal drowsiness and lethargy are "physical condition records," not blood sugar measurements

"I feel incredibly sleepy after lunch today," or "I feel lethargic in the afternoon." Keeping a note of these feelings in a notebook or on your smartphone can be a clue to understanding the ups and downs of your physical condition. However, sleepiness and lethargy also occur due to factors other than blood sugar. Sleep deprivation, temperature, and work-related fatigue can also cause similar sensations. A physical condition record is intended to help you learn your "patterns for days when you feel sleepy" and is not a numerical indicator of how your blood sugar actually moved. Keeping this distinction in mind will help you avoid becoming overly anxious or, conversely, being too dismissive when you look at the records.

Consult a medical institution regarding concerning changes

As you continue to keep records, you may notice changes such as drowsiness or lethargy occurring repeatedly after certain meals, or feeling stronger than before. In such cases, it is recommended that you consult a medical institution without waiting for your next checkup, rather than relying on your own judgment. As mentioned above, it can be difficult to see post-meal changes from checkup results alone, so while your physical condition record may not serve as direct evidence for a diagnosis, it will be useful as supporting material when explaining your situation to a doctor.

How to read the nutritional information on protein bars chosen for snacks?

When choosing a protein bar for an afternoon snack, you might be unsure about what to look for on the package. Here, we introduce what you can read from the numbers for carbohydrates, protein, dietary fiber, and the ingredient list.

Choose based on the balance of carbohydrates, protein, and dietary fiber

When choosing a protein bar, do you decide based only on the amount of protein? Checking the amount of carbohydrates as well can help you see whether it is suitable as a snack. Since carbohydrates consist of sugar and dietary fiber, if both are listed on the nutritional information, confirm the estimated amount of sugar as "Carbohydrates minus Dietary Fiber." The Ministry of Health, Labour and Welfare's e-Health Net describes dietary fiber as a food component that is difficult for human digestive enzymes to digest and reaches the large intestine without being absorbed in the small intestine (Ministry of Health, Labour and Welfare e-Health Net). Since it is digested and absorbed in the body differently than sugar, it is important to pay attention to the breakdown of carbohydrates, not just the total amount. It is a good habit to compare the figures for protein, dietary fiber, and carbohydrates on a regular basis.

Points to confirm on the ingredient list

In addition to the figures in the nutritional information, be sure to look through the ingredient list. Ingredients are listed in descending order of the amount used, so looking at the first few items will tell you what the main raw materials of the bar are. Products with white sugar or starch syrup at the top versus those with soy or nuts at the top are quite different in content, even if both are called "protein bars." Be sure to check the types of sweeteners and allergen labeling before purchasing.

Related information is introduced in How long does drowsiness from a glucose spike last? Causes and countermeasures and How to choose and eat snacks that won't raise your blood sugar, so please refer to these as well.

Comparing BRAIN PRO ingredients and nutritional information with other companies

Even with protein bars, the amount of sugar, dietary fiber, and ingredients vary by product. After checking the figures for BRAIN PRO, let's compare them side-by-side with other companies' products.

Check the sugar and dietary fiber figures for BRAIN PRO

One 35g bar of BRAIN PRO contains 190 kcal, 11.1g of protein, 13.5g of fat, 7.1g of carbohydrates (4.9g of sugar, 2.2g of dietary fiber), and 0.4g of salt equivalent. Sugar is kept to 4.9g using stevia and agave syrup, and as mentioned above, it contains 2.2g of dietary fiber, a component that reaches the large intestine. Ingredients include almond paste, pea protein, almonds, soy puffs, and lion's mane mushroom powder; it does not use white sugar, preservatives, wheat, casein, trans fatty acids, animal-derived raw materials, or artificial coloring. As it contains soy and almonds as ingredients, people with allergies to these should be careful.

Differences seen in a comparison table with 4–5 other products

Protein bars vary greatly by product in the distribution of sugar and dietary fiber, not just the amount of protein. When you align the figures displayed on the official websites and packages of each company, the differences become clear.

Product	Content	Sugar	Artificial Sweetener	White Sugar	Protein (Source)
Myprotein Layered Protein Bar Birthday Cake	60g	21g	Used (Sucralose)	Used	20g / Milk, Soy
in Bar Protein Baked Choco	42g	11g	Used (Sucralose)	Used	15.8g / Soy, Milk
ZAVAS Protein Bar Chocolate Flavor	44g	Not listed (Sugars 7.6g)	Used (Sucralose)	Used	17.2g / Milk, Soy
SOYJOY Calorie Control 80 Strawberry	18.1g	6.9g	Not used	Used	2.4g / Soy
BRAIN PRO	35g	4.9g	Not used	Not used	11.1g / Plant-based (Pea)

Those who want to keep sugar low should choose based on the sugar-to-protein ratio, while those who prioritize satiety should check the amount of dietary fiber. We recommend BRAIN PRO for those who want to take in dietary fiber while keeping sugar intake low.

Frequently Asked Questions

Can granola suppress glucose spikes?

The amount of sugar in granola varies by product, so it cannot be said unconditionally that it can suppress glucose spikes. Types coated in dried fruit or sugar are high in sugar, and depending on how you eat them, they can lead to rapid rises in blood sugar. When choosing, we recommend that you check that sugar or starch syrup is not at the top of the ingredient list and verify the amount of sugar and dietary fiber in the nutritional information.

Does eating two meals a day make glucose spikes more likely to occur?

It cannot be said for sure that this will always happen, but it is said that the longer the interval between meals, the greater the potential for a larger-than-usual rise in blood sugar at the next meal. If you eat two meals a day, consider the length of time between meals and try to be conscious of the order in which you eat, starting with vegetables or protein rather than focusing only on carbohydrates.

Summary

Glucose spikes are difficult to detect from medical checkup results alone, and daily small choices such as eating order, drinks, and light exercise after meals have an impact. There are many adjustments you can try from today's meal without special food or equipment. If persistent drowsiness or lethargy concerns you, try keeping a record of your physical condition and consider discussing it during your next medical checkup or consulting a medical institution.