Fructose, glucose, sucrose… we all know these terms. But what's the deal with all these names for sugar? Is there good sugar and bad sugar? – With the help of a little chemistry (don't worry, you don't need to dig out your dusty school chemistry knowledge), we want to explain the differences between fructose and glucose in this article.
Fructose and glucose - sugar as an essential substance?
It's quite clear: Our bodies need sugar. We think about its use for energy, cell growth, and so on. However, our bodies don't need sugar in the form of table sugar, but rather blood glucose (Yudkin & Lustig, 2014, p. 43).
But how much of it do we need? The figures for Germany speak for themselves: In 2022, Germans consumed an average of 34.8 kilograms of sugar per person. That's almost double the amount that the World Health Organization (WHO) has recommended for many years as the maximum amount of sugar to consume. For comparison: People in indigenous societies consume around 3 to 5 kilograms of sugar per year (Wölnerhanssen, 2020). The alarming fact is that our bodies do not require this external supply of sugar. Sugar from additional sources is purely a luxury product that our bodies do not need (Lustig, 2019; Wölnerhanssen, 2020).
Reason enough to take a closer look at the matter.
Basic knowledge about sugar
The general term "sugar" is used colloquially to describe many different substances. These should, however, be named and considered separately. Fundamentally, sugar belongs to the carbohydrates. Depending on the number of sugar molecules, a distinction is made between:
- Simple sugars (monosaccharides)
- Disaccharides and
- Complex sugars (polysaccharides)
Common table sugar ( sucrose ) consists of glucose and fructose – more precisely, of one molecule of glucose and one molecule of fructose ( Yudkin & Lustig, 2014, p. 43 ).
Fructose and glucose are both monosaccharides. They are therefore each a single sugar molecule. .
Glucose and fructose – what do these terms stand for?
Glucose is a white, water-soluble, and sweet-tasting powder. It is an important energy source for the human body. The brain also requires glucose as a nutrient. In humans and animals, glucose is stored in the form of glycogen, while in plants it is stored as starch. Fructose is also a white powder that is more easily soluble in water and tastes sweeter than glucose. You can find even more background information about glucose and its different types in this video .
Both fructose and glucose have the molecular formula C6H12O6 . However, they differ in their chemical structure and belong to different chemical groups (Lustig, 2019, pp. 258-259). It's no wonder that there are so many differences between glucose and fructose . .
Processing of glucose and fructose in the body
The human body can generally absorb sugar in the form of simple sugars via the bloodstream. When sucrose (table sugar) is ingested, the body must break it down into glucose and fructose. If sugar is ingested not as sucrose, but as glucose or fructose, it can be processed directly. But what happens to the fructose and glucose in the body?
Glucose enters the bloodstream via the intestines and can be directly converted into energy by the cells. Fructose, on the other hand, is primarily converted into fat in the liver and is not directly used for energy production ( Wölnerhanssen, 2020 ).
Glucose is stored in the body as glycogen. Furthermore, glucose intake causes a significant increase in blood sugar levels and the release of insulin. Satiety hormones are also released (Lustig, 2019, pp. 156-157). In contrast, fructose does not affect blood sugar levels or insulin release in the body. Satiety hormones are also not released (Wölnerhanssen, 2020).
Fructose and glucose in foods
Glucose occurs naturally in many foods.
Fructose , or fruit sugar, is found primarily in fruits and honey, as the name suggests. It is also increasingly found in processed foods. This is because fructose has a much higher sweetening power than glucose. Fructose is twice as sweet as glucose in the same quantity. Therefore, less fructose is needed than glucose to sweeten a dish. Since fructose is much cheaper to produce than sucrose (table sugar), it has been increasingly added to processed foods in recent decades (Yudkin & Lustig, 2014, p. 43). You can learn more about fructose in processed foods and why the artificial sweetness of fructose can be problematic in this video .
Now you might be wondering: What about fruit then? Doesn't it contain fructose? – You're absolutely right. However, fruits and vegetables contain many other nutrients, fiber, and vitamins in addition to fructose and glucose. This means that you're not only ingesting glucose and fructose, but also many other nutrients. Furthermore, the fiber they contain prevents you from absorbing too much sugar at once, slowing down its absorption in the body. This allows the liver to keep pace with the sugar intake. Therefore, it's not so easy to consume too much sugar from natural foods like fruits and vegetables (Lustig, 2019, pp. 171-173).
And what does a juice cleanse look like?
During an organic juice cleanse, you take a break and consciously abstain from solid food, from which you normally obtain the energy your body needs. The juices are your only source of nutrition and therefore also your only sugar intake. With our cold-pressed I·DO juices, you consume the sugar and nutrients of several servings of fruits and vegetables per day. However, sugar intake is limited during this time, as the amount of juice per day is precisely defined.
Of course, no added sugar is added to our I·DO juices . Thanks to cold pressing, your body also benefits – unlike when consuming conventional pasteurized juices – from the full range of nutrients and minerals from the fresh fruits and vegetables.
Conclusion
One thing is certain: not all sugar is created equal. Just to reiterate: sucrose is table sugar and belongs to the disaccharides, consisting of fructose and glucose. Fructose and glucose are both monosaccharides (simple sugars).
Less sugar – whether glucose or fructose
As with all nutrients, balance is key! A balanced diet with sufficient amounts of all essential nutrients covers the body's need for glucose and fructose. Sugar should only be consumed through foods in which it occurs naturally. Therefore, consciously choose to consume sugar in its naturally occurring form through fruits, vegetables, grains, etc. Excessive sugar consumption can have a detrimental effect on the body's organ systems ( Wölnerhanssen, 2020).
In the following magazine articles, you'll learn even more about sugar, because fructose and glucose aren't the only forms in which sugar can be consumed. There's also plenty to discover about other types of sugar, such as cane sugar, alternatives like agave syrup, and sugar additives.
Sources
Berneis, K (2012). The search for the sweet placebo. Not all sugar is created equal! Swiss Medical Forum, 12(1-2):6-7.
Lustig, RH (2019). The bitter truth about sugar – How obesity and other chronic diseases develop and how we can defeat them. 4th edition. Munich: Riva-Verlag.
Wölnerhannsen, K. (2020). Refined sugar – valuable energy or physiological nonsense? Quintessence of Dentistry, 71(5).
Yudkin, John & Lustig, Robert P. (2014). Pure, white, deadly: Why sugar is killing us – and how we can prevent it. Lünen: Systemed Verlag.
