What’s the problem with fizzy drinks?

Fizzy drinks are a major source of the type of sugars we’re advised to cut back on. ‘Free sugars’ are those added to food and drinks, rather than found naturally in substances like fruit and milk, but also include syrups, honey, concentrated fruit purées and juices. Consuming too many ‘free sugars’ poses various health risks such as weight gain, tooth decay, heart disease and type 2 diabetes. In the UK, 16% of an adult’s ‘free sugar’ intake and nearly a third (29%) of that for children aged 11-18 years comes from fizzy drinks like cola.


As we learn more about the dangers of sugar, it appears fizzy drinks may be especially problematic. They have been formulated to hit our ‘sweet spot’ – that perfect point at which taste and mouthfeel stimulate the brain’s reward system and we feel good. That’s why a chilled can of your favourite fizz is hard to resist.

Read more about sugar and sweeteners, including how much sugar we should have in a day and how much sugar children should have.

Three different glasses of cola

How do different fizzy drinks compare?

The introduction of the Soft Drink Industry Levy (‘sugar tax’) in April 2018 prompted widespread reformulation of products, reducing many from 10g of sugar per 100ml to less than 5g per 100ml. Many of these reformulated products make use of the 11 low-calorie sweeteners that are approved for use within the European Union. The main four are aspartame, acesulfame K, sucralose and saccharin.

Acceptable daily intakes (ADI) for these sweeteners have been set, but, although manufacturers must state the sweetener used, they do not currently have to list the amount of sweetener on the drink’s label.

More like this

There are many different brands of soft drinks and the manufacturers undergo reformulation of their products regularly, so the figures below are approximate and given for illustration purposes only.

Calories, sugar and sweeteners per 100ml serving:

42 Kcal
10.6g sugar
Sweeteners – none

Diet cola
1.6 Kcal
0g sugar
Sweeteners – aspartame, acesulfame K

10 Kcal
2.1g sugar
Sweeteners – sucralose, saccharin

Diet lemonade
1 Kcal
0g sugar
Sweeteners – sucralose, saccharin

Ginger ale
13 Kcal
3g sugar
Sweeteners – saccharin, sucralose

Diet ginger ale
6 Kcal
0.5g sugar
Sweeteners – saccharin, sucralose

Elderflower pressé
32 Kcal
7.8g sugar
Sweeteners – none

Light elderflower pressé
19 Kcal
4.5g sugar (including fructose)
Sweeteners – none

Fruit-flavoured water
10 Kcal
2.3g sugar
Sweeteners – stevia

Sugar-free fruit-flavoured water
0 Kcal
0g sugar
Sweeteners – acesulfame K, sucralose

Boy in baseball cap drinking from a bottle of cola, profile

Is diet cola better than regular?

Diet drinks contain few calories and no sugar, making them appealing options for those wanting to reduce their sugar intake and cut calories. The health effects of artificial sweeteners, including the widely used aspartame, remain controversial and concerns regarding their use are growing. One area of ongoing research is the influence these sweeteners have on our gut and oral microbiome and the knock-on consequences for blood sugar control, among other areas.

That said, many experts believe that sweeteners are safe to consume up to their acceptable daily intake for the general population. The one exception is infants and young children (one to three years) who have specific nutritional needs and increased energy requirements. In addition to this, those with the rare condition phenylketonuria should avoid all products containing aspartame.

How much caffeine is in a can of cola?

Low doses of caffeine can be useful, as it may make you feel more alert, energised and sharpen your memory. However, higher amounts – especially for certain sensitive people – may disrupt sleep, increase blood pressure and lead to anxiety.

In cola, caffeine is used as a flavouring. Soft drink manufacturers are limited as to the amount of caffeine they can add to regular fizzy drinks – the limit being 150mg per litre. On average, a standard 330ml can of cola contains about 32mg caffeine, whereas the diet version may contain slightly more at 42mg. So-called ‘energy’ drinks that include caffeine for its stimulating effect may contain more than 150mg per litre and for this reason are required to carry warnings that they are not suitable for children or pregnant and breast-feeding women.

How does the caffeine in a can of cola compare to other drinks and snacks?

  • Can of regular cola (330ml) – 32mg
  • Can of ‘diet’ cola (330ml) – 42mg
  • Can of ‘energy’ drink (500ml) – 160mg
  • Brewed coffee 1 mug (200ml) – 70-140mg
  • Instant coffee 1 mug (200ml) – 30-90mg
  • Tea 1 mug (200ml) – 45mg
  • Bar of milk chocolate (50g) – 10mg
  • Bar of 75% cocoa chocolate (50g) – 75mg

All figures are approximate

Read more about caffeine

A child's hand holding a glass of cola

The bottom line…

While sugary fizzy drinks may be consumed in moderation as part of a varied, balanced diet, excessive consumption of these and other sources of ‘free sugars’ may have detrimental effects on your longer-term health. The diet version of your favourite drink may offer a means of reducing your sugar intake but shouldn’t be seen as a long-term alternative because they still pose a problem for dental health. Ideally limit your intake to occasional and focus instead on plain, carbonated or unsweetened flavoured water.

Cola contains caffeine and, based on current scientific opinion, children and other sensitive people should consume it, and other sources of caffeine, in moderation. Pregnant and breast-feeding women are advised not to have more than 200mg of caffeine from whatever source, over the course of a day. If you are used to drinking cola regularly and you decide to cut back, do so gradually to minimise the effects of caffeine withdrawal.

There are many different brands of fizzy drinks and manufacturers undergo reformulation of their products regularly, so the figures quoted are approximate and given for illustration purposes only.

Now read:
Why is sugar bad for me?
8 ways to cut down on sugar
Sugar substitutes: aspartame explained
Are fizzy drinks bad for you?

Have you reduced how much cola you drink? Share your experience in the comments below…


All health content on bbcgoodfood.com is provided for general information only, and should not be treated as a substitute for the medical advice of your own doctor or any other healthcare professional. If you have any concerns about your general health, you should contact your local healthcare provider. See our website terms and conditions for more information.

Comments, questions and tips

Choose the type of message you'd like to post

Choose the type of message you'd like to post