A sugar-free diet: four weeks without sugar, step by step

A sugar-free diet does not mean you can never eat fruit again. The World Health Organisation (WHO) recommends limiting free sugars: sugar added to food and drink by manufacturers, cooks or yourself, and sugar from honey, syrup and fruit juice. The WHO explicitly excludes sugar found in fresh fruit, vegetables and milk. This is how we also understand ‘sugar-free’ in this guide. You’ll receive a four-week plan that starts with the easiest area to tackle – drinks – along with the most common hidden forms of sugar and an honest account of what happens during sugar withdrawal.

What does a sugar-free diet mean?

Three specialist bodies set the guidelines. The WHO advises adults and children to consume less than 10 per cent of their daily energy intake from free sugars. It estimates that consuming less than 5 per cent – around 25 g or six teaspoons a day – would bring additional benefits; the WHO classifies this second recommendation as conditional. The German Nutrition Society (DGE), together with the professional associations for obesity and diabetes, has endorsed the 10 per cent limit: for a daily intake of 2,000 kcal, this amounts to a maximum of 50 g of free sugars – intended as an upper limit, not as the amount one should consume.

In 2022, the European Food Safety Authority (EFSA) was unable to identify a level of sugar consumption below which the risk of tooth decay and certain chronic diseases does not increase. Its conclusion: added and free sugars should be kept as low as possible, whilst ensuring that the diet provides sufficient nutrients.

Fruit, vegetables and milk remain on the plate. Bananas contain around 17 g of sugar per 100 g, apples 13 g, carrots 6 g, and 100 ml of cow’s milk contains around 5 g of lactose – according to the WHO definition, these are not free sugars. It’s a different story with juice: apple or grape juice contains 11 to 17 g of sugar per 100 ml, and this sugar counts as free sugar.

How much sugar do we eat in Germany?

More than the recommended amount. According to data from the National Dietary Survey II, analysed in the consensus paper by the German Nutrition Society (DGE), the German Obesity Society and the German Diabetes Society, 13.9 per cent of energy intake among women aged between 15 and 80 comes from free sugars, compared with 13.0 per cent among men. The proportion is highest amongst adolescents and young adults, at around 17.8 per cent for 15- to 18-year-old women and 18.5 per cent for women aged between 19 and 24.

It is revealing to look at where the sugar comes from. Confectionery accounts for 36 per cent of free sugars, fruit juices and nectars for 26 per cent, and soft drinks for a further 12 per cent. Taken together, this means that 38 per cent comes from drinks – more than from sweets. In terms of consumption, fruit juices, nectars and other soft drinks totalled 148 litres per capita in 2017, the same amount as bottled water.

Why you should start with drinks

When it comes to drinks, you can cut down on a lot of sugar by making just one simple swap. 100 ml of lemonade or cola contains 10 to 11 g of sugar, whilst 100 ml of fruit nectar contains 17 g. Even a 200 ml glass contains 20 to 34 g of free sugars. According to the WHO, a can of soft drink can contain up to 40 g of free sugars – about ten teaspoons. Energy drinks contain on average around 100 g of sugar per litre, so a 250 ml can contains around 25 g.

By way of comparison: half a litre of fizzy drink containing 10 to 11 g of sugar per 100 ml contains 50 to 55 g – as much as the total daily upper limit of 50 g based on a 2,000 kcal diet.

The DGE recommends drinking around 1.5 litres a day, ideally water or unsweetened tea. It does not recommend sugar-sweetened drinks. If you like juice spritzers, it’s best to mix them yourself – that way, you decide how much juice to add. You can find out how much water you need and how to work out your daily intake in the guide ‘Drinking Water’. We explain what the planned sugar tax on drinks means in the article ‘Sugar Tax’.

What about ‘light’ drinks? The WHO advises against using sweeteners to control body weight and recommends reducing the overall sweetness of one’s diet. According to the AOK, sugar substitutes such as xylitol or erythritol do not help people to wean themselves off sweet things either. Find out more in ‘Sugar or sweetener?’ and in our overview of sweeteners.

If you find plain water a bit boring: according to the nutrition facts table, our flavoured varieties contain 0 g of sugar, and the lists of ingredients for all varieties do not include any sweeteners. The flavour comes from natural flavourings and citric acid. Energy – Blackcurrant & Pomegranate contains caffeine and is not recommended for children, pregnant women or breastfeeding mothers. You can find all our varieties under ‘Flavoured Water’, and ideas for making your own at home under ‘Make your own flavoured water’. You can read why we use no sugar and no sweetener on the page ‘Drinks without sugar and without sweetener’.

Your four-week plan

The AOK advises cutting down on sugar gradually, rather than cutting out all sources of sugar at once. The plan therefore adds one area each week. Once you’ve made a change, you stick with it.

Make a note of how you’re getting on with less sugar, perhaps in a diary. This will help you spot any changes and realise where your limits lie. If natural yoghurt or pancakes with no sugar don’t taste right yet, reduce the sugar slowly, bit by bit: your sense of taste is used to a certain level of sweetness and needs time to adjust.

Sugar has many names

Sugar is not always listed as ‘sugar’ in the ingredients list. The following terms also refer to sugar or sugar-rich ingredients:

• Sucrose, glucose (grape sugar), dextrose, fructose (fruit sugar), lactose, maltose and raffinose
• Glucose syrup, glucose-fructose syrup, fructose-glucose syrup, starch syrup, caramel syrup and invert sugar syrup
• Malt extract, barley malt extract and maltodextrin, which, depending on the type, contains up to 20 per cent sugar
• Sweetened whey powder, whey products and milk powder
• Honey, grape fruit sweetener, date powder, agave syrup, fruit concentrates, fruit purées and dried fruit such as raisins

Manufacturers are not required to specify the quantities of individual types of sugar. The order in which ingredients appear on the list of ingredients provides a clue, as ingredients listed near the top indicate a high proportion. However, if several types of sugar are spread throughout the list of ingredients, it is often impossible to estimate the total sugar content. In the nutrition facts table, ‘sugar’ includes all monosaccharides and disaccharides, including those naturally present in fruit or milk. We explain how to read an ingredients list step by step in our guide to reading ingredients lists.

Advertising slogans can be helpful too – if you know what they mean:

• ‘Sugar-free’: no more than 0.5 g of sugar per 100 g or 100 ml. A litre of ‘sugar-free’ fizzy drink may therefore contain up to 5 g of sugar.
• ‘low in sugar’: no more than 5 g of sugar per 100 g; for drinks, no more than 2.5 g per 100 ml.
• ‘reduced-sugar’: at least 30 per cent less sugar than comparable foods, whilst containing no more than the same number of kilocalories.
• ‘No sugar’: No sugar or other sweetening ingredients have been added. However, the product may naturally contain sugar.

Claims such as ‘naturally sweet’ or ‘sweetness from fruit only’, on the other hand, say nothing about the actual sugar content. Be careful with ‘sugar-free’ sweets too: they often contain sugar substitutes such as sorbitol, xylitol, maltitol or isomalt, and most of these have a laxative effect.

Sugar withdrawal: What’s the truth?

Many people describe the first few days without sugar as withdrawal. However, whether sugar in the strict sense is addictive is a matter of debate. The Hamburg Consumer Advice Centre considers the claim to be scientifically untenable: the neurotransmitter dopamine is released not only in response to sugar, but to all ‘natural rewards’, and the brain reacts very differently to drugs. The distinction is, however, a grey area, and further research is needed here. A review by the University of Cambridge found little evidence of sugar addiction in humans. Addiction-like behaviour, such as binge eating, was only observed in animal studies when sugar was available intermittently.

However, it is still possible to experience symptoms when making the switch. According to the AOK, people who are used to a high-sugar diet are more likely to feel the effects of a sudden change. It lists possible symptoms as including, amongst others, light-headedness or dizziness, nausea, tiredness, low mood, sleep disturbances and food cravings.

A small study from the US investigated this in relation to drinks: 25 overweight adolescents, who would normally drink at least three sugary drinks a day, were asked to drink only water and milk for three days. They reported stronger cravings for these drinks, lower motivation and reduced well-being; headaches were also mentioned more frequently. The researchers themselves describe these findings as preliminary indications.

If you cut out cola or energy drinks, you’ll also be cutting out caffeine – a 330 ml can of cola contains around 35 mg. The German Federal Institute for Risk Assessment lists withdrawal symptoms such as headaches, tiredness and irritability following regular high caffeine consumption. To combat cravings, the AOK advises: drink plenty of fluids, get enough sleep and get some exercise in the fresh air, rather than heading for the fridge.

Four weeks sugar-free: What’s realistic in terms of before and after

Accounts of people going four weeks without no sugar mention, amongst other things, an improved sense of taste, reduced sugar cravings, less hunger, less tiredness and better skin. The AOK classifies these as individual experiences: some people notice a difference quickly, others notice nothing at all because the period is too short, whilst others experience side effects.

A study by the Monell Chemical Senses Centre in Philadelphia shows that taste does indeed adapt. For three months, one group replaced 40 per cent of the calories from simple sugars with fat, protein and complex carbohydrates, whilst a control group continued to eat as before. In the first month, both groups rated the sweetness equally. In the second month, the low-sugar group perceived lightly sweetened custard as more intense; in the third month, they rated the custard as around 40 per cent sweeter than the control group. The effect was weaker with drinks, and the participants’ perception of how pleasant the sweetness was did not change. The groups were small, and researchers from PepsiCo were involved in the study.

For you, this means: four weeks is a good start, but not the end of the story. The AOK comes to the same conclusion – your health benefits from a long-term change in habits, not from a short-term challenge. The WHO and the DGE recommend reducing your sugar intake, not cutting it out completely.

Frequently Asked Questions

Sources

1. World Health Organisation (WHO): WHO calls on countries to reduce sugar intake among adults and children, 4 March 2015. who.int
2. DAG, DDG and DGE: Consensus paper: Quantitative recommendation on sugar intake in Germany, December 2018. dge.de
3. EFSA Panel on Nutrition, Novel Foods and Food Allergens (NDA): Tolerable upper intake level for dietary sugars. EFSA Journal 2022;20(2):7074, 28 February 2022. doi.org
4. German Nutrition Society: Eating and drinking well – the DGE’s recommendations, accessed 16 September 2026. dge.de
5. 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
6. 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
7. Food Transparency (Federal Association of Consumer Organisations): Sugar has many names, as at 9 February 2021. lebensmittelklarheit.de
8. Consumer Advice Centre: Sugar and sugar substitutes: How to spot sweeteners in food, as at 5 April 2024. verbraucherzentrale.de
9. Hamburg Consumer Advice Centre: How the sugar lobby conducts research and presents its arguments, as at 6 November 2023. vzhh.de
10. AOK Health Magazine (Volker Zapf, fact-checked): Giving up sugar: What are the benefits of a month without sugar?, 8 August 25. aok.de
11. AOK Health Magazine: Living Sugar-Free: 5 Steps to a Diet No Sugar, 19 August 2020, updated 25 January 2023. aok.de
12. European Journal of Nutrition (Westwater ML, Fletcher PC, Ziauddeen H): Sugar addiction: the state of the science, 2016. doi.org
13. Appetite (Falbe J, Thompson HR, Patel A, Madsen KA): Potentially addictive properties of sugar-sweetened drinks among adolescents, 2019. doi.org
14. American Journal of Clinical Nutrition (Wise PM, Nattress L, Flammer LJ, Beauchamp GK): Reduced dietary intake of simple sugars alters the perceived intensity of sweet taste but not its perceived pleasantness, 2016. doi.org
15. ACQUA REAPER: Product labels, 07–08/26.
16. Acqua Reaper: Product label for Energy Blackcurrant, as at 07/26.