Why are blood sugar spikes a problem—and how can they be avoided?

Do you constantly feel tired after eating, or get hungry again sooner than expected? Your blood sugar level is often to blame. We’ll explain how blood sugar spikes occur, how to avoid them, and how stable blood sugar levels support energy, satiety, and metabolism.

What does the term “blood sugar” actually mean?

Blood sugar refers to the concentration of glucose in the blood. Glucose is the body’s primary source of energy; the brain and certain cells, in particular, rely on a continuous supply. Glucose reaches the organs and cells via the bloodstream, where it is used to produce energy.¹

What happens to blood sugar after a meal?

After eating, blood sugar rises because carbohydrates are broken down into simple sugars in the digestive tract and absorbed into the blood as glucose.² In response, the body releases insulin, a hormone that ensures glucose is transported from the blood into the cells, where it is either used for energy or stored for later.³

What are blood sugar spikes, and why are they problematic?

It’s normal for blood sugar levels to rise after a meal. However, sharp increases—known as blood sugar spikes—are problematic. The body responds by releasing large amounts of insulin, causing blood sugar levels to drop rapidly—often even below the initial level.⁴ In the short term, this can lead to energy slumps, fatigue, and difficulty concentrating. Cravings are also a common consequence, often occurring shortly after the last meal: The drop in blood sugar signals to the brain that the body needs more fuel.^4,5,6

In the long term, frequent blood sugar spikes can harm metabolism: They can increase the risk of chronic diseases, slow down fat burning, and thus promote weight gain, since persistently elevated insulin levels inhibit the release of fat from cells.^7,8,9 In short: the more frequent and pronounced the spikes, the greater the strain on your metabolism. Conversely, stable blood sugar levels can help reduce cravings, maintain a more consistent energy level, and relieve the strain on your metabolism in the long term.^6,10

What affects blood sugar levels?

How much blood sugar levels rise after a meal depends primarily on the composition of the meal. Foods high in carbohydrates and sugar cause blood sugar to rise quickly and significantly, while dietary fiber, protein, and fat can flatten and delay the rise.¹¹ This is because dietary fiber slows digestion and glucose absorption in the intestines—as a result, glucose enters the bloodstream more gradually.¹² Proteins and fats also slow gastric emptying, thereby moderating the rise in blood sugar after a meal.^13,14

Which foods cause blood sugar to rise particularly sharply?

• Starchy foods low in dietary fiber, such as white bread, pasta, white rice, or breakfast cereals. The starch they contain is quickly broken down into glucose and enters the bloodstream rapidly.
• Sugary foods and beverages, including candy, cakes, sweetened dairy products, sugary drinks, and fruit juices. They provide readily available sugar without the slowing effect of dietary fiber.

What practical tips can help slow the rise in blood sugar?

Blood sugar levels can be stabilized by carefully choosing the composition and order of meals, as well as by exercising after eating. It’s not about deprivation, but about making smart choices in everyday life.

• The order makes all the difference: If you start a meal with high-fiber foods, followed by sources of protein and fat, and save the carbohydrates for last, you can significantly flatten the rise in blood sugar after eating.^15,16 Specifically, this means: start with vegetables or salad, followed by, for example, meat, fish, tofu, or legumes, and then rice, potatoes, or pasta. For mixed dishes where it’s hard to follow this order, it helps to eat a serving of vegetables or salad before the main meal.
• Combining carbohydrates: Carbohydrate-rich foods have a less pronounced effect on blood sugar when eaten together with protein, fat, or dietary fiber.¹⁷ In practice, this means combining bread with eggs, cottage cheese, or nut butter, or eating fruit with nuts or plain yogurt.
• Selected plant compounds and micronutrients: Certain plant compounds and micronutrients can further help regulate blood sugar levels after high-carbohydrate meals. These include extracts from white mulberry, green tea, chromium, and inositol—which are discussed in more detail below.
• Exercise after eating: Even a short walk of about 10 minutes after a meal can help slow the rise in blood sugar. The activated muscles absorb more glucose directly from the blood.^18,19,20,21

Which plant compounds and nutrients can help keep blood sugar levels in balance?

Certain plant compounds and micronutrients, such as white mulberry, chromium, green tea, or inositol, can help regulate blood sugar levels after carbohydrate-rich meals.

• White mulberry: The plant compound DNJ-1 (1-deoxynojirimycin), which occurs naturally in the leaves of the white mulberry tree, inhibits a specific enzyme that breaks down carbohydrates into glucose.²² This delays carbohydrate digestion, causing glucose to enter the bloodstream more slowly.²³ In a double-blind study, white mulberry leaf extract was even shown to reduce the postprandial rise in blood sugar by up to 40%.²⁴
• Chromium: This is a trace element that enhances the action of insulin and helps maintain normal blood sugar levels.²⁵
• Green tea: Green tea contains catechins, which can support insulin action and fat metabolism.^26,27 They can also help reduce oxidative stress and thereby ease the burden on the metabolism.²⁶
• Inositol: This is a vitamin-like substance that can support insulin action and thus help stabilize blood sugar levels.^28,29