Defining sugar and sugars can be tough, as the proper nomenclature is often different from the colloquial names we hear in the media and use ourselves. It is also somewhat different from the nomenclature used in labelling legislation. Take your time and try to comprehend how it works.
Carbohydrates = sugars = saccharides – proper chemical names of sugars
Let’s start with a very broad term: the name ‘carbohydrates’. In chemical terms, carbohydrates are organic molecules composed of carbon, oxygen and hydrogen. More specifically, they are aldehydes or ketones bonded with hydroxyl groups. Various carbohydrates differ in terms of:
- impact on blood sugar levels.
Carbohydrates can also be referred to as sugars or saccharides, all these names are correct. Carbohydrates include:
- Simple carbohydrates (monosaccharides);
- Complex carbohydrates (complex sugars, polysaccharides), which include:
- Disaccharides, double sugars (composed of two sugar units),
- Oligosaccharides (consisting of 3 to 10 sugar units).
For instance, potato or buckwheat starch is a complex carbohydrate; sucrose (white sugar in the sugar bowl) and lactose (milk sugar) are disaccharides; maltodextrin is an oligosaccharide; while glucose and fructose are examples of simple sugars.
A completely separate group, that is not chemically classified as sugars, are the polyols you probably know as healthier sweeteners: xylitol, maltitol, sorbitol, erythrol and most sweeteners ending with -ol.
Carbohydrates can be also classified as digestible carbohydrates (that can be digested by humans and transformed into energy) and indigestible carbohydrates, or dietary fibre.
You have gone through the strictly scientific part of your reading. Now you know that ‘sugars’ can mean buckwheat starch, lactose from milk, totally indigestible dietary fibre, or fructose from fruits, to name just some. Sugars (carbohydrates, saccharides) are a very broad group of molecules. You may be well aware now that they will affect our bodies in different ways and some of them will even be indigestible by humans. There are healthier kinds of carbohydrates, which should be eaten in larger quantities (such as dietary fibre, starch) and sugars which should not be consumed in excess (such as sucrose).
Names of sugars and carbohydrates in dietetics vs. food industry
You instinctively know for sure that if you hear someone say they are ‘cutting down on sugar’, they do not mean cutting down on the entire group of carbohydrates altogether. That’s because the nomenclature used in the food industry is somewhat simplified. It differs from the chemical names. According to European Union legislation, the two most important definitions are:
- Carbohydrates – any carbohydrates which are metabolised by humans, including polyols.
- Sugars – all monosaccharides and disaccharides present in food, but excluding polyols.
If the nutrition label of a product states ‘of which sugars’, you can expect it to mean the presence of simple sugars, such as glucose and fructose, but also double sugars: sucrose, lactose, maltose etc. The term ‘sugars’, however, excludes polyols such as xylitol, sorbitol, or maltitol, as well as dietary fibre and complex carbohydrates.
FAO experts make things a little bit more difficult by using the term ‘simple sugars’ when referring to all monosaccharides and disaccharides in food. Sucrose and lactose, although in chemical terms they are not simple sugars but disaccharides, are therefore colloquially included in this group.
‘Total carbohydrates’ on the label refers to all types of carbohydrates available in the product, whether digestible or not. To calculate their amount in a food item, we simply deduct the content of all other ingredients (proteins, fats, water, alcohol). They are called ‘carbohydrates by difference’.
The term ‘digestible carbohydrates’ covers all carbohydrates metabolised by the human body, as well as polyols. But the indigestible dietary fibre is excluded. The term ‘digestible carbohydrates’ is not always present on the packaging. Oftentimes, if you want to check their content, you need to deduct dietary fibre from ‘total carbohydrates’ on your own.
That’s not all yet, we should also define the term ‘added sugars’, or ‘free sugars’. These are carbohydrates delivered by ingredients added in the production and preparation process to the final product. The term free sugars also includes sugar from natural ingredients, such as honey, syrups, fruit juices or fruit preserves.
While some simple sugars have the same chemical structure, depending on where they come from, they will have to be classified in other groups. For instance, fructose which is naturally present in apples is classified as a simple sugar, but not as added or free sugar. The same fructose, when it comes from honey, will be considered as an added and free sugar.
Recommendations on sugar consumption – which sugars are ‘good’, and which are ‘bad’ for you?
Let’s get more specific: you should not be concerned about complex carbohydrates. It is a good idea to keep the intake within the 45-65% range, but you don’t need to cut down on them. They are the primary source of energy for your brain, muscles and thyroid. Your best bet would be fibre-rich whole grain sources of carbohydrates, which are slow to digest and to raise blood sugar levels. However, this must not be confused with knowing how to tell ‘bad’ sugar from ‘good’ sugar.
WHO experts strongly recommend keeping free sugars at less than 10% of the dietary energy intake. Ideally, we should cut them down even further to 5% of the daily energy intake. Free sugars: what are they? Free sugars are sugars added to food items and meals by producers at the preparation stage in the form of:
- white sugar,
- cane sugar,
- coconut sugar,
- maple syrup,
- other sugar syrups,
- dried fruits,
- fruit juices,
- fruit juice concentrate,
- fruit jam,
- other fruit preserves.
This means that WHO does not advise against a specific molecule, but against adding sugar in general. The World Health Organisation clearly emphasises that we should not seek to restrict carbohydrates from fresh fruit, vegetables and dairy products, but recommends against sweetening. Don’t eat chocolate, don’t take sugar in your tea, avoid jams (even the healthy ones), other substances with added sugar, and even fresh fruit juices. Here are some examples:
- Does WHO consider natural yoghurt which is not sweetened in any manner as a source of free sugars? – NO, it doesn’t count towards the 10% limit, you can eat it without remorse.
- So is an apple a source of free sugars according to WHO? – NO, it doesn’t count towards the 10% limit, you can eat it without remorse.
- Is natural yoghurt into which you put apple chunks a source of free sugars? – again NO, according to WHO you don’t have to count the sugars from these ingredients towards the recommended 10%.
- Is natural yoghurt with raisins a source of free sugars? – YES, raisins are processed fruit, so the carbohydrates from raisins count towards the free added sugar limit.
- Is 100% apple juice a source of free sugar according to WHO? – YES, sugar from juices counts towards the daily limit.
- Is natural yoghurt with an extra teaspoon of honey a source of free sugars according to WHO? – YES, sugars from honey must be counted towards the 10% limit.
- Does WHO consider natural fruit yoghurt with added sugar as a source of free sugars? – YES, the producer added the sugar to the yoghurt, and this sugar must be counted towards the daily maximum of 10%.
- According to WHO, is fruit-flavoured yoghurt which is labelled as ‘sugar-free’ but is sweetened with apple juice concentrate a source of free sugars? YES – sugar from apple juice concentrate is considered as ‘free sugar’ and counts towards the 10% limit set by WHO.
Now you should understand a little bit better what the WHO recommendations are about. They don’t count sugars coming naturally from dairy products, fresh vegetables and fresh fruit towards the 10% daily intake limit, because they believe “there is no evidence that these substances are harmful to health”. However, WHO warns against products to which sugar or some other, theoretically more natural sweetener has been added.
Why did they introduce these limits? The World Health Organisation justifies its recommendations in great detail in a 59 pages long document, providing specific reasons in support of these recommendations and a lot of evidence. Briefly speaking, by reducing free sugars below 10% of the daily energy intake, we take care of two aspects:
- Maintaining a healthy weight and preventing obesity and all its complications, such as diabetes, fatty liver syndrome, heart diseases, cancer, etc.
- Dental health.
Reading carbohydrate (sugar) content from a product label: an example
If you want to cut down on sugar, you need to read labels. Actually, it’s not as difficult as it may seem. To help you understand and review the essential definitions of sugars and carbohydrates, you can analyse an imaginary product and its label as an example. Let’s try to drill down into the content of all carbohydrates in natural yoghurt with fruit and cereals. Here’s what you can read from the label:
- of which saturated
- of which sugars
- Carbohydrates: 12.6 g – this is the total content of carbohydrates, digestible and undigestible, in fruit yoghurt with cereals.
- Of which sugars: 9.9 g – this is the content of simple carbohydrates (monosaccharides and disaccharides) in fruit yoghurt with cereals. This includes sugars naturally occurring in yoghurt as well as sugar added by the manufacturer.
- Dietary fibre: 1.3 g – this is the content of potentially undigestible dietary fibre in fruit yoghurt with cereals.
So how do we know how many ‘teaspoons’ of sugar the producer has added to this yoghurt? Even if you can see sugar on the list of ingredients, this information is not expressly provided anywhere on the label. You need to check the sugar content in natural yoghurt to be able to actually separate milk sugars from the sugar added by the producer to make the yoghurt sweeter.
From a label of natural yoghurt, it follows that it contains 6.2 g of carbohydrates, all 6.2 g being ‘sugars’.
Let’s compare this to the value read from the fruit and cereal yoghurt packaging. 9.9-6.2 = 3.7 g of sugar added by the producer per 100 g of the product.
WHO is ‘warning us’ and wants us to count 3.7 g of sugar instead of the total of 9.9 g stated on the label towards the 10% daily energy intake limit.
Summary: Sugars cannot be clearly divided into ‘bad’ and ‘good’ sugars. We should aim at restricting simple sugars (glucose, fructose, sucrose, etc.) in our diet, but not at the expense of dairy products and fresh vegetables and fruit. However, we should avoid all kinds of sugar added to foods, even when they are disguised and we can’t see them at first glance.
World Health Organisation WHO; Guidelines: Sugars intake for adults and children; 2015 https://www.who.int/publications/i/item/9789241549028 dostęp: 3.09.2022.
Normy żywienia dla populacji Polski i ich zastosowanie. Pod redakcją M. Jarosza, E. Rychlik, K. Stoś, J. Charzewskiej; Warszawa: Narodowy Instytut Zdrowia Publicznego, 2020. ISBN: 978-83-65870-28-5