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Sugar withdrawal

Why do we get sugar withdrawal symptoms?

Cutting down on sugar has a lot of health benefits, including reducing your risk of obesity and type 2 diabetes. However, some people report unpleasant sugar withdrawal symptoms - such as headaches and tiredness when they try to eat fewer sugary foods. But why is this the case and how can you manage these side effects?

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Why does giving up sugar cause withdrawal symptoms?

The symptoms of sugar withdrawal include headaches, decreased energy, an inability to concentrate and mood changes1. Although it’s not completely understood why these side effects happen, research shows it's likely linked to the impact sugar intake has on our brain chemistry.

Eating sugar triggers a release of different chemicals, including endorphins - which boost your mood and reduce pain - and dopamine, which is linked to pleasure, satisfaction and reward. Sugar stimulates the brain's reward system and ultimately, it makes us feel good - so we are likely to want to eat more sugary food and drinks.

These kinds of changes can lead to dependence and addiction2. Therefore, giving sugar up may trigger unwanted side effects.

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Symptoms of sugar withdrawal

Not everyone struggles when they cut back on sugary foods. In the long-term, it can make you feel good and improve your health. However, symptoms of sugar withdrawal can be both physical and mental. You may feel tired, irritable and anxious, or you may have headaches - but these issues are temporary.

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Why can the keto diet cause sugar withdrawal symptoms?

Ketogenic diets involve cutting all sugars out of your diet, including natural sugars found in fruit. The aim of these high-fat, low-carb diets is to put the body into a state of ketosis, which is when the body burns fats instead of carbohydrates as its main fuel source3. Ketosis can have unpleasant symptoms similar to sugar withdrawal.

Reema Patel, dietitian at Dietitian Fit & Co, says the symptoms of ketosis are colloquially known as keto flu.

"Initially, these symptoms include headaches, fatigue and nausea, but again they will soon go away," she says. Being dehydrated can also mimic the sugar withdrawal symptoms, so it is important to make sure you keep well hydrated if you are cutting down on sugar.

"If you have a lack of sodium in the diet, you may also experience symptoms such as headache and low mood," says Patel.

How can you manage sugar withdrawal symptoms?

Set achievable goals

There may be health reasons to switch to a very low-sugar diet, but it can be easier to gradually reduce the amount of sugar you eat rather than cutting it out all at once.

Making small food swaps can be helpful. For example, switching sugary snacks for foods that are higher in proteins, fats and wholegrains. Swap sugary fizzy drinks and energy drinks with plain or sparkling water - adding some slices of lemon or lime can add flavour.

Eat enough fibre

"Be sure that you are consuming enough dietary fibre," says Patel. "This will help regulate blood sugar levels, reducing dips that can lead to cravings. Dietary fibre comes from vegetables, wholegrains, pulses, beans as well as nuts and seeds.

"It’s also important to include a good mix of proteins, healthy fats and complex carbohydrates with meals to help keep you full and reduce cravings."


Exercise can improve symptoms of reducing sugar, as physical activity releases endorphins which boost your mood and wellbeing.

Improve your sleep hygiene

Poor sleep has long been known to make us crave sugary and higher calorie foods4. Working on your bedtime routine - by avoiding screens before bed and creating a relaxing atmosphere - can help improve your sleep. If you're well-rested, you'll be less likely to give in to sugar cravings.

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Further reading

1. Falbe et al: Potentially addictive properties of sugar-sweetened beverages among adolescents.

2. Avena et al: Evidence for sugar addiction: Behavioural and neurochemical effects of intermittent, excessive sugar intake.

3. Masood et al: Ketogenic diets.

4. Markwald et al: Impact of insufficient sleep on total daily energy expenditure, food intake, and weight gain.

Article history

The information on this page is peer reviewed by qualified clinicians.

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