Baby and You

Low-calorie sweeteners are used in a variety of foods and beverages as an alternative to sugar. Johanna Hignett takes a closer look at what they are, what they do and how they work

A liking for sweetness is inherent from an early age. Sweetness is one of our preferred tastes and evolved to help the selection of safe and nourishing foods because many unsuitable or unsafe foods have unpleasant tastes. Breast milk has a slightly sweet flavour, so it’s usual that infants tend to like sweet flavours from the start and acceptance of other flavours may take time.

“Sugar provides 4 calories per gram”


Sugar, or sucrose, is the most common source of sweetness in the diet, but other sugars such as fructose, glucose and lactose are also sweet to varying degrees. Sugars provide 4 calories per gram and research suggests that a higher consumption of sugar sweetened beverages may lead to a higher risk of type 2 diabetes and weight gain. Frequent intake of sugary foods and drinks may also be associated with the development of dental decay.

Replacements that provide sweetness of sugar but without the calories or dental risks have been sought for many years, although, in practice, it’s difficult to mimic all the functions of sugar.

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Replacing sugar

Scientifically, sugar is quite unique. Not only is it sweet, but it has many other functions and plays a role to the overall quality and appearance of foods.

These days, a range of sugar alternatives are available and they can replace some, but not all, the functions of sugar.

Sweeteners in detail

Today’s sweeteners can be broadly split into two categories: ‘low calorie intense sweeteners’ and ‘bulk sweeteners’.

Intense sweeteners provide a very strong, sweet taste and are used in very small amounts. For instance, Aspartame is 200 times sweeter and Sucralose 320 – 1000 times sweeter than sucrose. These can be used to provide sweetness in liquid based products, such as drinks, yogurts, dessert mixes and puddings, but aren’t suitable in cakes and biscuits as they don’t provide the volume of sugar and aren’t suitable for baking.

As the amount of sweetener used is extremely small, the calories provided are low too. For example, by choosing a typical can of fizzy drink sweetened with intense sweetener, you would save around 100 – 140 calories compared to a sugar sweetened version. Intense sweeteners are not linked with the dental problems seen with sugar, but ‘acids’ in soft drinks may cause dental erosion.

Bulk sweeteners are compounds also called ‘polyols’ and provide sweetness with fewer calories than sugar. Polyols provide around 2.4 calories a gram, compared to 4 in sugar. They are mainly used in confectionery products such as boiled sweets, chocolate and chewing gum. These usually contain fewer calories and also help to reduce the dental issues associated with the normal sugar contained in them. In fact, research has concluded that polyols can have a positive impact on the hardness and strength of tooth enamel. Take care though, as if you eat too much they can have a laxative effect and cause diarrhoea. Foods containing more than 10 per cent of added polyols must be labelled with the statement ‘excessive consumption may produce laxative effects’ and they are not permitted in soft drinks in the European Union (EU).

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Pros and cons

As with so many factors relating to food and nutrition, there are pros and cons when considering the role of sweeteners in foods and in your diet. Given that sugar performs many functions in foods, it is no surprise that sweeteners can fulfil one or two of the functions of sugar but do not fully replace them all.

Both intense and bulk sweeteners can play useful roles in specific foods and drinks, helping to reduce or exclude sugar whilst still providing the desirable sweet taste. There are, however, limitations:

Preservative effect – using low calorie sweeteners in food and liquids provides sweetness but no preservative effect. Preservatives may additionally be required in some foods to ensure safe consumption and an acceptable shelf life.

Bulk effect – sugar bulks out cakes and biscuits which low-calorie sweeteners don’t do because they’re used in very small quantities.

Colour – sweeteners don’t caramelise, so don’t give the golden-brown colour seen in baked foods.

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Sweeteners and health

Replacing sugar in foods and drinks with sweeteners reduces the sugar and calorie level of a product, but does this, in turn, help people?

Yes – research suggests that substituting full sugar products with foods and drinks sweetened with low-calorie sweeteners may be useful in reducing total energy intake and, in turn, body weight. To manage your weight, it’s important to include regular physical activity and take care with your overall calorie intake too.

Sweeteners can also help in reducing total intake of sugars to achieve the dietary guidelines. The UK’s Scientific Advisory Committee on Food for intakes states that free sugars should be no more than 5 per cent of total calories. Free sugars are ‘all monosaccharides and disaccharides added to foods by the manufacturer, cook or consumer, plus sugars naturally present in honey, syrups and unsweetened fruit juices. Under this definition, lactose when naturally present in milk and milk products is excluded’.


Like any food additive, sweeteners have to be tested and approved as safe for use in food before they are permitted for use. All sweeteners have been tested for safety and have an ‘E number’, a mark that shows they have been tested and approved by the EU authorities. In fact, many studies have used intakes so high that humans would not typically consume such amounts. Overall, experts across Europe have classified sweeteners as safe for consumption.

Bulk sweeteners offer particular benefits in confectionery products, but may have a laxative effect if consumed in excess. This is a natural response to higher intakes of these compounds and although the effects don’t last, it can be uncomfortable and distressing, especially in children.

Sweeteners or sugar?

Whether you choose foods or drinks sweetened with sweeteners or with sugar depends largely on the type of food or drink, your motivation and your personal taste.

Sweeteners can help to reduce sugar intake, so may help to achieve weight management goals. They may also help dental health. Equally, reducing overall intakes of sugar and sweetened foods will help to reduce total sugar intakes.

Sugar intakes are too high and action is needed. Whether you choose to switch to sweeteners, cut down on sugar, or do both, is a personal choice.

References available upon request.

Johanna Hignett, Nutrition Consultant (RNutr), is a highly experienced nutritionist with over 20 years’ experience working primarily as a nutritionist in the food industry, as Head of Nutrition Science and Communication for Nestle UK before setting up Nourish Consulting over ten years ago.

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