Fructose – healthy sweetness or disease-causing agent? We explain!

Fruchtzucker – gesunde Süße oder Krankmacher? Wir klären auf!

Fructose – much loved and wildly controversial! 

Fruit sugar or fructose is a naturally occurring sugar that is found primarily in fruit and has received a lot of attention in recent years with regard to its health effects. Once celebrated as a healthier alternative to other types of sugar, fructose is now viewed increasingly critically and is suspected of promoting obesity and numerous diseases. Does this mean that you should now eat no or less fruit? In this blog article, we examine the technical aspects of fructose and shed light on its effects on health and metabolism and the importance of fruit in a healthy diet.

Fructose – sweet & delicious – healthy or unhealthy? 

First of all, let's clarify the term - what is fructose actually? Fructose is a natural type of sugar that occurs in many types of fruit, vegetables and honey. Chemically speaking, it is a simple sugar that belongs to the monosaccharides and, at around 400 kcal/100 g, provides the same number of calories as glucose. However, fructose tastes almost twice as sweet as glucose (eg dextrose), but triggers a lesser feeling of satiety in the body and is also metabolized differently by the organism.

What does the body do with fructose?

Fructose is often considered a healthier alternative to other types of sugar because it has a lower glycemic index and is thus metabolized largely independently of insulin. This means that fructose does not affect blood sugar levels as much as glucose. This is why fructose was and is often recommended for diabetics. However, fructose is mainly metabolized in the liver and can be converted directly and quickly into fat there. This increased fat synthesis can lead to fat accumulation in the liver and promote diseases such as non-alcoholic fatty liver disease. In addition, research suggests that high fructose consumption can also increase insulin resistance in the long term, which is associated with an increased risk of obesity, type 2 diabetes, heart disease and liver disease. The effects of fructose on metabolism are therefore more complex than previously thought.

The recommended daily amount of fructose is approximately 25-50 g or 5-10% of calorie intake, or more if you are physically active or doing sports.

But what does this mean for you – is fruit now unhealthy and should you eat no or less fruit?

Nutrition and fructose – Natural is simply healthier 

Fructose is found in many natural foods, especially fruit. It is interesting to note that the fructose content of fruit varies greatly. Apples contain around 6 g, grapes around 8 g and raspberries around 2 g of fructose per 100 g of fruit. (1. see However, fruit and vegetables contain health-promoting vital substances and nutrients such as vitamins, minerals, trace elements, fiber and valuable secondary plant substances. Consuming fructose from these natural sources is generally harmless and is an essential part of a healthy and balanced diet.

But why the fuss about fructose? Fructose is not only found in fruit, but is now one of the most popular and cheapest raw materials in the food industry. Whether in soft drinks, sweets, cereal bars, fruit juices and countless industrially processed foods, fructose often only provides empty calories without any significant vital substances. The added fruit sugar in foods is called, for example, fruit sugar, fructose, sugar, invert sugar syrup, fructose syrup, isoglucose, corn syrup, fructose-glucose syrup, glucose-fructose syrup or juice concentrate. The fructose content does not have to be declared separately on the product. High fructose corn syrup (HFCS), a fructose-glucose mixture made from corn with a high fructose content, is particularly problematic. This very cheap HFCS is found mainly in soft drinks and floods the body with empty calories.

Numerous studies suggest that excessive consumption of fructose in the form of added fructose sources promotes obesity, metabolic syndrome, the development of fatty liver disease and many other diseases. It is important to note that the majority of this research indicates that normal consumption of fructose in the form of natural foods such as fruits and vegetables does not have any negative health effects.

A current quote from research: "But what about fruit? Can it also be dangerous for us?" Johnson says: "No. Fruits have much less fructose, which is also bound to fiber. The body can only absorb it slowly from the intact plant cell structure. In addition, the intestines break down small amounts of fructose independently before they enter the body." (2. see, Dtsch Arztebl 2023; 120(10): A-437 / B-375 )

That's why fresh fruit is good for you

  1. Rich in vital substances

Fresh fruit is an excellent source of a variety of vitamins, minerals, trace elements and fiber. These vital substances are important for your health and support your immune system, your intestinal health, your cell and bone health and numerous other metabolic processes. 

  1. Nature's Pharmacy - Secondary Plant Ingredients

Particularly well-known are the so-called antioxidants, which help to protect the body from oxidative stress and damage caused by free radicals. Numerous types of fruit are particularly rich in these antioxidants. These can help reduce inflammation, reduce the risk of chronic diseases such as heart disease, cancer and neurodegenerative diseases, and improve cell and skin health. In addition, fruit contains numerous other secondary plant substances with positive effects on your metabolism and your health. 

  1. Dietary fiber

The perfect food for your microbiome! Fruit is a natural and excellent source of fiber. This can promote gut health, regulate bowel movements, lower cholesterol levels and reduce the risk of cardiovascular disease and type 2 diabetes. If you want to know more about this, then take a look at our blog - Fiber .

© Monika Löff (Fructose_Blog_(c)Monika Löff)

Conclusion – nature can simply do it better

Regular consumption of fresh fruit makes an important contribution to a balanced diet and a healthy lifestyle. 2-4 handfuls of fruit a day provide you with plenty of nutrients, vital substances and fiber. Whether an apple or a pear as a fruity snack, a handful of delicious berries in muesli, a fresh homemade fruit or vegetable drink or a nutrient-rich smoothie - enjoy the colorful variety of fruits, preferably organic, regional, seasonal and adapted to your individual needs. At the same time, however, you should reduce the consumption of foods to which fructose has been added as a source of sugar to a minimum. Soft drinks, concentrated juices, industrially processed, pasteurized or otherwise artificially preserved fruit juices in particular often contain a lot of fructose, few vital substances and often only provide empty calories. Avoid these and thus long-term negative effects on your health and instead give yourself and your body what it needs - true to the motto - it's natural and it simply tastes better that way!


Dtsch Arztebl 2023; 120(10): A-437 / B-375


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