Is Coke Zero unhealthy? An explanation of the ingredients in zero-calorie drinks

Is Coke Zero unhealthy? No expert body makes a blanket judgement – but there are clear assessments of the individual ingredients. Sugar-free, caffeinated soft drinks are sold with sweeteners, and these sweeteners are subject to authorisations, maximum limits and labelling requirements. This guide explains the typical ingredients, the assessments by the WHO and the International Agency for Research on Cancer regarding aspartame, and how to read a label. We do not evaluate specific products; the list of ingredients on the respective can is always the decisive factor.

What ‘Zero’ means on the label

Zero-calorie drinks exist because sugary fizzy drinks contain a lot of sugar: According to the WHO, a can of sugar-sweetened soft drink can contain up to 40 g of free sugars, whilst the WHO and the German Nutrition Society (DGE) recommend that free sugars should account for less than 10 per cent of total energy intake – a maximum of 50 g per day on a 2,000 kcal diet.

‘Zero’ is a marketing claim. The law specifies when a drink may be advertised as ‘sugar-free’: it must contain no more than 0.5 g of sugar per 100 ml. This claim says nothing about sweeteners. Whether any are present is indicated by the list of ingredients and the statement ‘contains sweetener(s)’.

What ingredients are typically found in zero-calorie fizzy drinks?

The guidelines for soft drinks set out what is standard practice for lemonades:

• Water and carbon dioxide as the base.
• Flavourings – Limes are made with flavouring extracts or natural flavourings as a minimum.
• Something to satisfy a sweet tooth, such as different types of sugar or sweeteners. In low-calorie fizzy drinks, added sugar may be partially or entirely replaced by sweeteners.
• Caramel colouring – common in caffeinated soft drinks and their flavour-matched decaffeinated versions.
• Citric acid.
• Caffeine in caffeinated soft drinks: Most cola drinks contain around 100 mg of caffeine per litre.

The exact ingredients of a particular drink are listed only on its label.

Sweeteners: permitted, but subject to maximum limits

Sweeteners are food additives. They may only be used in certain foods and within specified maximum limits; these are based on the ADI – the amount a person can consume daily over a lifetime without any adverse health effects being expected. Sweeteners are virtually calorie-free and can be 30 to 37,000 times sweeter than table sugar.

On the packaging, they are listed under the category ‘sweeteners’ along with their name or E number; in addition, the words ‘contains sweetener(s)’ must appear in conjunction with the product name. A separate requirement applies to aspartame: ‘Contains aspartame (a source of phenylalanine)’ or ‘Contains a source of phenylalanine’.

Three sweeteners commonly found in soft drinks

The Hamburg Consumer Advice Centre describes all 14 sweeteners authorised in the EU. It also lists three of these as being typically used in soft drinks:

Acesulfame K and sucralose are excreted by the body unchanged and enter water bodies via sewage treatment works; the Federal Environment Agency has classified both as relevant trace substances in 2024.

Aspartame: what the WHO and the International Agency for Research on Cancer said in 2023

In July 2023, the International Agency for Research on Cancer (IARC) and the Joint Expert Committee on Food Additives (JECFA) of the WHO and FAO published their assessments of aspartame:

• IARC: Aspartame is ‘possibly carcinogenic to humans’ (Group 2B), based on limited evidence in humans. This classification describes the strength of the evidence – not the level of risk associated with a specific intake level.
• JECFA: The ADI of 0 to 40 mg per kilogram of body weight remains unchanged; according to the committee, consumption within this limit is safe.
• To put this into perspective: if a can of diet soft drink contains 200 or 300 mg of aspartame, an adult weighing 70 kg would have to drink more than 9 to 14 cans a day to exceed the ADI – not taking into account any other sources of aspartame.

Both organisations are calling for more and better research. You can find a detailed fact-check on sweeteners and cancer under ‘Are sweeteners carcinogenic?’.

The WHO guidelines on sweeteners

Regardless of individual substances, the WHO has, since May 2023, advised against the use of sweeteners to control body weight or reduce the risk of non-communicable diseases. According to its assessment, sweeteners offer no long-term benefit in terms of reducing body fat. The recommendation is classified as ‘conditional’ and does not apply to people with existing diabetes. The Hamburg Consumer Advice Centre summarises the situation as follows: in the short term, sweeteners may help with weight loss, but in the long term the risk of weight gain increases – the calories saved are usually offset by other foods. There are only a few studies on the effects of sweeteners on children. The guide ‘Sugar or Stevia?’ explains the comparison between sugar and sweeteners.

Caffeine in cola drinks

According to the Federal Institute for Risk Assessment, a 330-ml can of cola contains around 35 mg of caffeine. Most cola drinks contain around 100 mg per litre and therefore do not require the warning ‘High caffeine content’, which is only mandatory from 150 mg per litre. According to the EFSA, 3 mg of caffeine per kilogram of body weight is considered safe for children and adolescents. The caffeine levels of other drinks are listed in the caffeine table.

Is Cola Zero unhealthy? What the launch of Paulaner Cola Zero reveals

The sugar-free range continues to expand. According to a press release from the Paulaner Brewery Group dated 28 October 2026, the Munich-based company will launch Paulaner Cola Zero across Germany in January 2027 – in food and drink retail outlets as well as in the hospitality sector, in standard bottle and can sizes. The sugar-free version complements the classic Paulaner Cola, which has been on sale since its market launch in spring 2026. The industry news service lebensmittelzeitung.net reported the move on 28 October 2026.

The company cites market conditions as the reason why this is set to pay off: according to its figures, zero-sugar variants account for around 36 per cent of the German cola market, the segment is recording double-digit growth rates, and around a third of German households buy sugar-free cola. CEO Jörg Biebernick says that the company has been working on sugar-free and reduced-sugar products for a long time and does not need government tax regulations to do so.

For you, a product launch like this doesn’t change your assessment: ‘sugar-free’ only refers to the sugar content, not to sweeteners. Whether a drink contains any is indicated by the list of ingredients and the statement ‘contains sweetener(s)’ in conjunction with the product name. In the case of aspartame, the label will also state ‘Contains aspartame (a source of phenylalanine)’ or ‘Contains a source of phenylalanine’.

We don’t sell cola. Our flavoured drinks have no sugar and no sweetener – according to the list of ingredients, they contain:

• Pink Grapefruit: Water, carbon dioxide, natural grapefruit flavouring, citric acid (acidity regulator).
• Lime & Mint: Water, carbon dioxide, natural lime flavouring, citric acid (acidity regulator), natural peppermint flavouring.
• Citrus: Water, carbon dioxide, citric acid (acidity regulator), natural citrus flavouring.

All three contain 1 kcal per 100 ml and do not taste as sweet as lemonade. The question of sweeteners therefore does not even arise in their case.

Zero, light or completely unsweetened?

If you don’t want either sugar or sweeteners, you have two options. The German Nutrition Society recommends water or other calorie-free drinks, such as unsweetened tea, as the best choice. And there are flavoured drinks with no sugar: Our Pink Grapefruit, Lime & Mint and Citrus varieties contain 0 g of sugar per 100 ml and, according to the list of ingredients, no sweeteners; the flavour comes from natural flavourings, with citric acid added. They therefore do not taste sweet like a fizzy drink – nor are they meant to.

Find out more in the guide ‘Sugar-free without sweeteners’.

Frequently Asked Questions

Sources

1. Product range expansion: Paulaner launches a zero-sugar version of cola (lebensmittelzeitung.net, 28 October 2026), accessed on 29 October 2026. lebensmittelzeitung.net
2. Paulaner expands its cola business and launches Cola Zero | Presseportal (presseportal.de, 28 October 2026), accessed on 29 October 2026. presseportal.de
3. Paulaner expands its cola business and launches Cola Zero (about-drinks.com, 28 October 2026), accessed on 29 October 2026. about-drinks.com
4. Sweeteners: What are sweeteners and sugar substitutes? (verbraucherzentrale.de), accessed on 29 October 2026. verbraucherzentrale.de
5. German Food Codex Commission: Guidelines for Soft Drinks, revised version dated 10 April 24, BAnz AT 16 May 24 B3. deutsche-lebensmittelbuch-kommission.de
6. European Commission: Nutrition claims (Annex to Regulation (EC) No 1924/2006), accessed 16 September 2026. food.ec.europa.eu
7. Consumer Advice Centre: Sweeteners: What are sweeteners and sugar substitutes?, as at 26 June 25. verbraucherzentrale.de
8. Hamburg Consumer Advice Centre: Sweeteners – Sweetness without regret?, as at 30 July 2026. vzhh.de
9. World Health Organisation (WHO): WHO calls on countries to reduce sugar intake among adults and children, 4 March 2015. who.int
10. DAG, DDG and DGE: Consensus paper: Quantitative recommendation on sugar intake in Germany, December 2018. dge.de
11. World Health Organisation (WHO), IARC, JECFA: Results of the hazard and risk assessment of aspartame published, 14 July 2023. who.int
12. World Health Organisation (WHO): WHO advises against the use of non-sugar sweeteners for weight control in newly published guidance, 15 May 2023. who.int
13. Food Transparency (Federal Association of Consumer Organisations): Caffeine labelling is not mandatory for all food products, as at 19 June 26. lebensmittelklarheit.de
14. Federal Institute for Risk Assessment (BfR): Questions and answers on caffeine and caffeinated foods, including energy drinks, FAQ dated 5 January 2026. bfr.bund.de
15. German Nutrition Society: It’s best to drink water, accessed 16 September 2026. dge.de
16. ACQUA REAPER: Product labels, as at 26 July.