A sugar detox is a popular idea, but scientifically we are talking about something simpler: cutting down on added sugar. We explain what the WHO recommends, what research says happens when you cut out sugar, where sugar hides on food labels, and offer a simple 7-day plan with no promises.
A sugar detox usually means a week or more without sweets, sugary drinks and other foods with added sugar. The word "detox" is used loosely here. Sugar isn't a toxin that needs to be "flushed out": your body uses it for energy, and your liver and kidneys remove unwanted substances every day. We explain this in more detail in our article "Body detoxification: does your body really need 'cleansing'?". So it's more honest to talk not about cleansing, but about giving up sugar, or at least cutting down.
In this article we draw on recommendations from the World Health Organization (WHO) and the European Food Safety Authority (EFSA), information from the UK's National Health Service (NHS) and peer-reviewed research on sweet taste perception, cravings and mood. You'll find the sources at the end of the article, and they are numbered in the text, for example [1]. We write about how sugar relates to hormones in our article on sugar and hormonal balance.
What does a sugar detox actually mean?
There is no official definition of a sugar detox. Some people give up only sweets, others fruit as well. Scientific recommendations are simpler: they are not about all sugar, but about free sugars [1, 2].
Free sugars and added sugars: what's the difference?
- Added sugar is sugar put into food or drink by the manufacturer, the cook or you: in tea, cake, yoghurt or a sauce.
- Free sugars is a broader term. The WHO includes all added sugar plus the sugars naturally present in honey, syrups, fruit juices and juice concentrates [2].
- The natural sugars in whole fruit, vegetables and milk are not counted as free sugars, so the WHO recommendations don't limit them [1, 2].
| Food | Is it a free sugar? |
|---|---|
| White and brown sugar | Yes |
| Honey, maple or agave syrup | Yes |
| Fruit juice, even without added sugar | Yes |
| Sugary drinks and sweets | Yes |
| A whole apple, berries, a banana | No |
| Vegetables | No |
| Plain milk and unsweetened yoghurt | No |
So giving up sugar doesn't mean giving up fruit. It's far more important to look at sugary drinks, sweets and processed foods.
How much sugar do the WHO and EFSA recommend?
The WHO recommends that free sugars make up less than 10% of daily energy intake, and that reducing them to 5% or less may bring additional health benefits [1, 2]. On a diet of about 2,000 kcal a day, 10% is about 50 g, or roughly 12 level teaspoons [2]. The 5% limit works out at about 25 g a day. The WHO bases these recommendations on evidence about unhealthy weight gain and tooth decay [1].
In 2022 EFSA assessed whether a safe upper limit for sugar intake could be set. The scientists could not identify one and concluded that intake of added and free sugars should be as low as possible within a nutritionally adequate diet [3]. The NHS advises adults to have no more than 30 g of free sugars a day, and children aged 7 to 10 no more than 24 g [4].
| Organisation | Recommendation | What it means in practice |
|---|---|---|
| WHO | Free sugars below 10% of daily energy | About 50 g (12 teaspoons) on 2,000 kcal |
| WHO | Ideally 5% or less | About 25 g a day |
| EFSA | Added and free sugars as low as possible | No safe upper limit could be set |
| NHS | Up to 30 g of free sugars for adults | Fruit juice and smoothies up to 150 ml a day |
What happens when you cut out sugar: what does research show?
Online, a sugar detox is often described day by day: headaches, the strongest cravings on day three, glowing skin by the end of the week. These accounts are based on personal experience, not research.
Does your perception of sweetness change?
It can, but not in a week. In a US study, 33 adults spent 3 months either on a diet lower in simple sugars or eating as usual [5]. In the first month there were no differences between the groups. In the second month, those eating less sugar rated a lightly sweetened pudding as sweeter, and by the third month the puddings tasted about 40% sweeter to them than to the control group. But how much they liked sweet taste didn't change: they enjoyed sweet foods just as much [5].
In a larger 2025 study, 180 adults ate food with a high, regular or low level of sweetness for 6 months. Liking for sweet taste didn't change in any group, and neither did other measured outcomes, such as energy intake [6]. This study looked at sweet taste in general, not just sugar, so it doesn't contradict the WHO advice to cut free sugars. It simply shows that the promise "after a week you won't want sweets any more" isn't backed by science.
Is sugar addictive, and is there "withdrawal"?
"Sugar addiction" and "withdrawal" sound convincing, but there is little evidence in humans. A 2016 scientific review found that addiction-like behaviour, such as bingeing, appeared only in rats given sugar intermittently after periods without food [7]. The review's authors found little evidence from human studies to support sugar addiction [7].
That doesn't mean the urge for something sweet is imaginary. It's often linked to habit, tiredness, long gaps between meals, or simply sweets sitting on the table. So the first days without sweets can be uncomfortable, but this is more about changing a habit than withdrawal of the kind seen with addiction. You'll find practical tips in our article "How to reduce sugar cravings".
Will you have more energy without sugar?
A 2019 meta-analysis combining 31 studies with 1,259 participants found that carbohydrates did not improve any aspect of mood [8]. In fact, within the first hour after eating carbohydrates, participants felt more tired and less alert than those given a placebo [8]. So the "sugar rush" is more myth than fact.
| Common claim | What research shows |
|---|---|
| "After a week you won't want sweets" | Liking for sweet taste didn't change even over 3–6 months [5, 6] |
| "Food will taste sweeter" | Possibly, but changes were seen only after 2–3 months [5] |
| "Sugar is as addictive as drugs" | There is little evidence for this in humans [7] |
| "Sugar gives you energy and lifts your mood" | More tiredness in the first hour, no improvement in mood [8] |
| "A sugar detox cleanses your body" | No, but less free sugar is in line with WHO and EFSA advice [1, 3] |
Important: these research findings are about reducing sugar and about nutrition in general. They do not describe the effects of any fruttberry product.
Where does added sugar hide?
Much of our added sugar comes not from the sugar bowl but from processed foods, so the most useful skill is knowing how to read a label. We cover this in detail in our article "Food labels: how to read them"; here is a short guide to sugar.
The nutrition table
The line "carbohydrates, of which sugars" shows all sugars: both added sugars and those naturally found in milk, fruit or vegetables [4]. So plain yoghurt or milk will show sugars even though nobody added any. The NHS says a food is high in sugar if it contains more than 22.5 g per 100 g, and low if it contains 5 g or less per 100 g [4].
The ingredients list
Ingredients are listed in descending order of weight, so the closer sugar is to the start of the list, the more there is. Sugar can go by many names [4]:
- Sugars ending in "-ose": sucrose, glucose, fructose, dextrose, maltose.
- Syrups: glucose-fructose syrup, corn syrup, maple and agave syrups.
- Other sources of sugar: honey, molasses, nectars, brown or cane sugar.
- Fruit juice concentrate and purées, when added for sweetness.
| Food | What to check on the label |
|---|---|
| Sugary drinks, iced tea | Sugars per 100 ml and in the whole pack |
| Fruit juices and smoothies | Even without added sugar they count as free sugars; the NHS suggests up to 150 ml a day |
| Fruit yoghurts and curd desserts | Whether sugar or syrup is among the ingredients |
| Breakfast cereals, granola | Sugars per 100 g and where sugar appears in the list |
| Sauces, ketchup, marinades | Sugar or syrups in the ingredients list |
| Bars labelled "healthy" | Honey, syrups, juice concentrate |
A 7-day sugar detox: a simple plan with no promises
This plan doesn't promise that your taste, skin or weight will change in a week. Its aim is simpler: over 7 days, review the main sources of added sugar in your diet and choose the habits you want to keep. Add one step each day.
- Day 1: drinks. Swap sugary drinks and juice for water, unsweetened tea or coffee. Drinks are one of the easiest sources of free sugars to spot [2, 4].
- Day 2: breakfast. Instead of sweetened cereal or a pastry, go for porridge or plain yoghurt with berries and nuts.
- Day 3: labels. Check your fridge and cupboard: yoghurts, cereals, sauces. Look for the names of sugars in the ingredients list [4].
- Day 4: snacks. Prepare snacks without added sugar: fruit, nuts, vegetables with hummus. You'll find ideas in our article "Healthy snacks: 7 simple fibre-rich recipes".
- Day 5: regular meals. Eat regularly so that long gaps don't turn into a quick grab for something sweet. Add vegetables, whole grains and pulses to your meals: fibre-rich food helps you feel full for longer [10].
- Day 6: dessert. If you fancy something sweet, choose fruit or berries.
- Day 7: review. Think about which changes were easy and which were hard. Pick 2–3 habits to carry on with. You don't need to give up sugar forever: what matters most is keeping free sugars below 10% of daily energy [1].
If you'd like daily reminders and meal ideas sent to your inbox, join our free 7-day no-added-sugar challenge.
Why fibre matters too
When cutting down on sugar, it's better to replace sweets with food rather than sweeteners: fruit, nuts, whole grains. That way you also get more fibre. EFSA considers 25 g of fibre a day adequate for normal bowel function in adults [9]. Increase your fibre intake gradually and drink more fluids, as a sudden change can cause bloating [10]. How much fibre you need and where to find it is covered in our article "How much fibre do you need a day?".
When should you talk to a doctor?
Cutting down on added sugar is generally safe for healthy adults. However, it's worth talking to a doctor or dietitian before changing your diet if:
- you have diabetes or take medication that affects blood glucose. Discuss dietary changes with your doctor and never change your medication dose on your own;
- you are pregnant or breastfeeding;
- you plan to change your child's diet;
- food and restrictions make you anxious, or you have had an eating disorder in the past;
- you notice unexplained weight loss, severe tiredness, dizziness or other unusual symptoms.
Fibre for every day: fruttberry fibre blend
We created fruttberry out of our own need: we wanted a fibre blend that would be enjoyable to drink every day. It's best to get fibre from food first, and if you still get too little, the blend can help top up your daily amount.
Ingredients
- Psyllium husk and ground psyllium seed (psyllium) are the base of the blend.
- Agave inulin is a soluble fibre obtained from agave. It is not agave syrup.
- Freeze-dried strawberries (12%) and blackcurrants (8%) provide flavour and colour from real berries, not flavourings.
- Glucomannan from konjac (Amorphophallus) tubers is another soluble fibre.
How much fibre is in one teaspoon?
100 g of the blend contains 77 g of fibre. An independent test by the KTU Food Institute found as much as 84.4 g of fibre per 100 g in a sample of our blend. One teaspoon (5 g) provides about 3.86 g of fibre and only 11 kcal. The blend contains no added sugar, gluten, lactose or preservatives, and it's suitable for vegans.
Stir one teaspoon into 200–250 ml of water and drink it straight away, and increase the amount every 3–4 days. Psyllium and glucomannan swell, so always take the blend with plenty of water: taking it with too little liquid carries a risk of choking. If you have difficulty swallowing, don't take this type of fibre.
All fruttberry dietary fibre products in one place.
Frequently asked questions about a sugar detox
Does a sugar detox really cleanse your body?
No. Sugar isn't a toxin that needs to be "flushed out". What's called a sugar detox usually means cutting down on added sugar, and that is exactly what the WHO and EFSA recommend [1, 3].
How much sugar can you have a day?
The WHO recommends getting less than 10% of daily energy from free sugars, about 50 g on 2,000 kcal, and ideally less than 5%, about 25 g [1, 2]. The NHS advises adults to have up to 30 g [4].
Do you have to give up fruit when cutting out sugar?
No. The natural sugars in whole fruit are not counted as free sugars [2]. Fruit juice is worth limiting: the NHS suggests no more than 150 ml a day [4].
Are honey and agave syrup healthier than sugar?
The WHO counts honey and syrups as free sugars, just like ordinary sugar [2]. So they count towards the same daily limit.
Is a week enough for your taste to change?
Probably not. In one study, perception of sweetness changed only in the second and third months, and liking for sweet taste didn't change [5, 6]. A week is a good start for reviewing your habits, but not the end result.
Sources
- World Health Organization. Guideline: sugars intake for adults and children. Geneva: WHO; 2015.
- World Health Organization. Healthy diet. Fact sheet, 2026.
- EFSA Panel on Nutrition, Novel Foods and Food Allergens (NDA). Tolerable upper intake level for dietary sugars. EFSA Journal. 2022;20(2):7074.
- NHS. Sugar: the facts. Reviewed 2023.
- Wise PM, Nattress L, Flammer LJ, Beauchamp GK. Reduced dietary intake of simple sugars alters perceived sweet taste intensity but not perceived pleasantness. American Journal of Clinical Nutrition. 2016;103(1):50–60.
- Čad EM, Mars M, Pretorius L, et al. The Sweet Tooth Trial: a parallel randomized controlled trial investigating the effects of a 6-month low, regular, or high dietary sweet taste exposure on sweet taste liking and various outcomes related to food intake and weight status. American Journal of Clinical Nutrition. 2026;123(1):101073.
- Westwater ML, Fletcher PC, Ziauddeen H. Sugar addiction: the state of the science. European Journal of Nutrition. 2016;55(Suppl 2):55–69.
- Mantantzis K, Schlaghecken F, Sünram-Lea SI, Maylor EA. Sugar rush or sugar crash? A meta-analysis of carbohydrate effects on mood. Neuroscience & Biobehavioral Reviews. 2019;101:45–67.
- EFSA Panel on Dietetic Products, Nutrition and Allergies. Scientific Opinion on Dietary Reference Values for carbohydrates and dietary fibre. EFSA Journal. 2010;8(3):1462.
- Harvard T.H. Chan School of Public Health. Fiber. The Nutrition Source. Reviewed 2022.
The information provided is general in nature and does not replace advice from a doctor or dietitian. Scientific data is presented about sugar, fibre and nutrition in general and does not describe the properties of any specific product. If you have a chronic condition, take medication, are pregnant or breastfeeding, talk to a healthcare professional before you start taking food supplements. A food supplement is not a substitute for a varied and balanced diet.
