What does an empty stomach mean and why is it important
An empty stomach means that there is nothing in the digestive tract to slow down digestion. In the morning, after 7–9 hours of sleep without food, the body is very responsive. When a lot of sugar hits an empty stomach, it is quickly absorbed into the blood. Blood sugar means the amount of sugar circulating in the blood and serving as fuel for the body. If this amount rises too quickly, the body reacts intensely.
Studies from 2020 show that as many as 65% of people who regularly eat sweet pastries for breakfast report morning fatigue even before noon. In 2025, similar numbers were confirmed by European nutrition studies.
What happens in the body after a sweet breakfast
When you eat a sweet breakfast, for example a muffin or sweetened coffee, sugar quickly enters the bloodstream. The body responds by releasing the hormone insulin, which helps sugar enter the cells to be used as energy. The problem arises when there is too much sugar and it comes in too quickly. Sometimes the body releases too much insulin, which causes a rapid drop in blood sugar. This is when the classic signs appear: hunger, poor concentration, nervousness, and shakiness.
This state even has a name: reactive hypoglycemia. This means that blood sugar drops too much after a meal because of the body’s excessive response. It’s not a disease, but a warning that the body doesn’t tolerate such a meal well.
Why do you feel worse after a sweet breakfast than before
Interestingly, many people feel worse after a sweet breakfast than before eating. Research from 2021–2024 shows that after meals high in added sugar, energy levels indeed rise quickly, but also fall quickly. For about 40% of people, there is a marked drop in energy after just 60 to 90 minutes. This means you’re even more tired than if you hadn’t eaten at all.
Folk practice described it very simply: sugar lifts you up, then drops you even more.
Why don’t we all react the same
It's important to note that not all people are the same. Some can eat a sweet breakfast and have no problems. Their bodies have a more stable blood sugar regulation system.
But research shows that sensitivity is higher among:
- people who sleep poorly,
- those under stress,
- people over the age of 40,
- people with fluctuating body weight.
In 2025, data showed that every third adult European has at least occasional problems with blood sugar fluctuations, even if they don’t have diabetes.
Sugar and the brain: why concentration suffers
The brain uses about 20% of all the body’s energy. It needs a steady supply of fuel. When blood sugar fluctuates, the brain feels it first. That’s why after a sweet breakfast, the following often appear:
- trouble concentrating,
- distractibility,
- reduced attention,
- irritability.
Research from 2022 showed that people who ate a high-sugar breakfast had up to 25% poorer cognitive performance in the morning compared to those who had a balanced breakfast.
What does a balanced breakfast mean
A balanced breakfast is not complicated. It doesn’t mean expensive supplements or special diets. It simply means that sugar is not alone. Proteins, fiber, and fats slow down sugar digestion. Proteins are the body’s building blocks, fiber aids digestion, and fats help maintain long-lasting satiety.
Traditional cuisine always knew this. Eggs, cottage cheese, dairy products, whole grain bread... these were common morning foods, not desserts.
Why sweet drinks in the morning do more harm
Sweet drinks are a particular problem. Juice, sweetened coffee, or energy drinks contain sugar in liquid form. Liquid sugar is absorbed even faster than solid sugar. One cup of sweetened coffee may contain up to 20 grams of sugar, almost half the daily recommendation. Studies from 2020 showed that sweet drinks in the morning are one of the biggest factors in morning fatigue.
What does folk wisdom say
In folk medicine, sweet breakfasts were almost nonexistent. Sweets were reserved for holidays, not everyday meals. In the morning, people ate simple, filling foods because they knew work awaited them. Sweets on an empty stomach were considered indulgence, not fuel.
Of course, the solution is not to completely ban sweets. It’s about the order. If you want something sweet, eat it after a meal, not instead of a meal. Even a small change in the morning is enough. Add protein or fiber. Yogurt, an egg, a piece of whole grain bread. For many, the difference in how they feel is noticeable within a few days.
Research from 2023 showed that people who replaced a sweet breakfast with a more balanced one reported 30% more energy in the morning and less craving for sweets.
And movement helps, too. Just 10–15 minutes of slow walking after breakfast helps the body use sugar. Sleep has a big impact. Less than 6 hours of sleep increases the risk of morning blood sugar fluctuations by up to 40%.
Coffee also has an effect. For some people, caffeine raises blood sugar even without sugar. That’s why it’s important to observe your body.
What to remember
Sweets on an empty stomach are not poison, but they’re also not a good way to start the day. The body perceives them as stress, not as help. The consequences show up quickly: fatigue, hunger, poor concentration...
If you want a calm morning, stable energy, and less craving for sweets, the solution is surprisingly simple. Feed your body first, then indulge your taste.
And one more thing... This isn’t a diet. It's basic self-care, something our ancestors knew — and today, science confirms it too.
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