ADHD and nutrition: does the ketogenic diet offer perspective?

Source: Jeleefstijlalsmedicijn

In this article, we discuss new evidence about how this diet may potentially have benefits for people with ADHD.

Many adults with ADHD experience challenges in concentration, energy, and impulse regulation. At the same time, many consider their way of thinking as an integral part of their identity, with unique strengths. Within this neurodiversity perspective, we present the ketogenic diet as a possible way to relieve certain symptoms, not as a correction of a ‘disorder’. Transparent information helps people with ADHD and their environment to together see if this suits them.

Author: Jaap Versfelt
Scientific reviewers: Nathalie van Vugt MSc, LBI alumnus; David Bezpalec, PhD candidate at LBI; Dr. Eline Dekeyster, associate professor Neurosciences and head of the LBI (Lifestyle Brain Interaction), Leiden University

Key insights from the article ADHD and nutrition

ADHD is becoming more common: ADHD is a condition that causes problems with attention, hyperactivity, and impulsive behavior. Since 2002, the use of ADHD medication in the Netherlands has increased sevenfold.
Energy deficits in the brain in ADHD: The brain consumes a lot of energy, primarily from glucose, derived from sugars and starch in food. In people with ADHD, however, brain metabolism seems to work less well. A shortage of energy in the brain can contribute to cognitive limitations that occur in ADHD.
The role of metabolic dysfunction: Metabolic dysfunction occurs when the body has difficulty converting food efficiently into energy. This is more common in people with ADHD.
Can the ketogenic diet be a solution? The ketogenic diet consists of lots of fats and few carbohydrates. This forces the body to use “ketones,” an alternative energy source that is produced from fat instead of glucose. Ketones can thus form an alternative fuel for the brain.
Evidence for the ketogenic diet: The ketogenic diet is standardly used in the treatment of epilepsy and shows promising results in Alzheimer’s, Parkinson’s, and cognitive improvements. Although direct evidence for ADHD is limited, mechanisms such as improved energy metabolism and reduced inflammation levels point to possible benefits for ADHD.
Safety considerations: The ketogenic diet is generally safe for adults. However, certain conditions must be excluded, such as rare metabolic disorders, the use of certain medications (e.g., insulin, lithium), and eating disorders. With long-term use, regular monitoring of cholesterol levels is recommended. For children, the diet is part of the standard treatment for epilepsy (usually for a limited period of two years), but there are no guidelines for other conditions. Medical supervision is therefore recommended before starting this diet.
Starting the diet: Starting a ketogenic diet can be challenging without guidance. Tools such as beginner’s guides and meal plans can facilitate the transition.
Conclusion: Although more research is needed, the ketogenic diet offers a possible alternative for managing ADHD symptoms, especially when standard treatments do not have sufficient effect.

1. What is ADHD

ADHD stands for attention deficit hyperactivity disorder. It is a condition that affects how people concentrate, manage tasks, and control impulses. ADHD can manifest in one or more of the following behaviors:

Inattention: This means having difficulty staying focused, being easily distracted, or having problems with organization.
Hyperactivity: This includes constant movement, restlessness, or talking a lot — even at inappropriate moments.
Impulsivity: Acting without thinking, interrupting others, or having difficulty waiting your turn.

Everyone experiences these behaviors sometimes. What makes ADHD different is that these behaviors occur frequently and in various situations — such as at school, at work, at home, or with friends. They also disrupt the daily life of someone with ADHD.

2. ADHD is becoming more common

More and more children are being diagnosed with ADHD. In 2023, more than 5% of Dutch parents indicated that their child between 4 and 12 years old had ADHD. Boys are diagnosed more often than girls: about 6.6% of boys versus 3.5% of girls (NJI, 2024). The number of people using ADHD medication has also risen sharply. In 2003, about 48,000 people in the Netherlands were prescribed ADHD medication such as Ritalin. By 2024, that number had risen to nearly 304,000.

Medication	2003	2010	2015	2020	2024	Growth
Dexamphetamine	12	4,287	24,643	37,610	61,197	+5,000%
Methylphenidate	48,430	140,421	193,774	195,196	255,806	+428%
Atomoxetine	-	5,885	4,260	4,736	6,897	-
Total	48,436	146,483	213,372	225,848	303,786	+527%

Figure 1. Development of ADHD medication use in the Netherlands. Source: GIP Databank.

What could be the cause of this increase and what can be done about it? To answer these questions, we first need to understand how the brain uses energy and what happens when this process does not work well.

3. The brain as an energy-intensive organ

The human brain consumes an extremely large amount of energy. Although it makes up only 2% of body weight, it uses about 20% of the body’s energy at rest. This energy comes primarily from glucose, a form of sugar in food. Carbohydrates in our diet — such as candy, soft drinks, bread, pasta, and rice — are broken down into glucose, which is transported to the brain via the blood. Glucose is the brain’s primary fuel.

But this dependence on glucose has a disadvantage. When glucose use is disrupted, the brain does not get the energy it needs to function well. This is especially important for people with ADHD:

ADHD affects focus, planning, and task management. These cognitive functions depend on brain areas that need a lot of energy to work well. Research shows that with complex mental tasks, the involved brain areas consume more energy. If the brain does not get enough energy, these tasks become more difficult.
Cognitive tasks require brain energy. In people with ADHD, scientists have discovered that certain parts of the brain — particularly those involved in focus and decision-making — use glucose less well. This reduced ability to convert glucose into energy is called “cerebral glucose hypometabolism” and has been observed in various brain disorders, including ADHD (Newman, 2011).
Brain energy may be disrupted in people with ADHD. A reduced ability to use glucose as an energy source occurs in various neurological conditions such as epilepsy, traumatic brain injury, bipolar disorder, and Alzheimer’s. This also applies to ADHD (Zametkin, 1990). This energy deficit could explain some problems of people with ADHD.

What can cause such energy deficits in the brain?

4. Metabolic dysfunction disrupts the use of glucose as brain energy

Metabolic dysfunction occurs when metabolism — the system that converts food into energy and nutrients — does not function well. This can disrupt the brain’s energy supply. Normally, the brain relies on glucose from food as its main energy source. Glucose is transported to cells via the blood and enters with the help of insulin, a hormone that acts as a “key” to open the cells.

In metabolic dysfunction, cells in the body, including brain cells, become less sensitive to insulin. This is called insulin resistance. As a result, less glucose enters the cells and the brain has difficulty getting enough energy.

Metabolic dysfunction increases the risk of physical conditions such as type 2 diabetes, heart attacks, and strokes. Additionally, it increases the chance of brain disorders such as dementia and Parkinson’s. When metabolic dysfunction manifests in measurable clinical features, such as increased waist circumference and high blood pressure, we speak of metabolic syndrome. This syndrome appears to be associated with ADHD (Yuan, 2022).

The relationship between metabolic dysfunction and ADHD is still being studied. Possibly this relationship is mutual: metabolic dysfunction may increase the risk of ADHD, while ADHD may lead to lifestyle choices that contribute to metabolic dysfunction.

Metabolic dysfunction is becoming increasingly common in the Netherlands. In the 90s, 19% of men and 12% of women between 28 and 59 years old had metabolic syndrome. By 2020, this had doubled to 36% of men and 24% of women (Bos, 2007; Sigit, 2020).

Factors such as eating lots of ultra-processed food, too little exercise, stress, lack of sleep, and exposure to harmful substances can contribute to metabolic dysfunction. Improving these habits can restore the body’s ability to use glucose as energy, supporting both physical and brain health.

5. Ketones as alternative fuel for the brain

The ketogenic diet is a dietary pattern that is rich in fats and very low in carbohydrates. This causes the body to reach a state called ‘ketosis,’ where it switches from using carbohydrates as the primary energy source to using ‘ketones’.

Ketones are special molecules that are made in the liver when the body breaks down fat. Normally, the brain relies on glucose (a form of sugar) from carbohydrates as fuel. However, when carbohydrate intake is very low — such as during fasting, prolonged exercise, or a ketogenic diet — the body begins to produce ketones. These ketones are transported to the brain via the bloodstream and provide energy there.

Remarkably, ketones after a very long fasting period (30 to 40 days) can cover up to 70% of the brain’s energy needs. The body still produces a little glucose for the brain via a process called ‘gluconeogenesis.’ In this process, glucose is produced from non-carbohydrate sources, such as proteins in meat, eggs, or beans.

This ability to use ketones as an energy source is a survival mechanism from human evolution. During periods of food scarcity, the body relied on fat reserves to produce ketones, so the brain could continue to function even without regular nutrition. Thanks to this adaptation, people could survive for weeks without food.

6. Evidence for the effectiveness of the ketogenic diet for brain disorders

The ketogenic diet has been studied as a possible treatment for brain-related conditions (Anderson, 2025). It is already widely used in the treatment of type 2 diabetes because it can improve blood sugar levels and help the body use insulin better (Goldenberg, 2021).

But what is the effect on the brain? Research shows that it can help with various brain disorders. Here are some examples:

Epilepsy. The ketogenic diet has been used for more than 100 years to treat epilepsy, especially in people for whom medication does not have sufficient effect (Jiang, 2022). For children, it is even included in official medical guidelines in the Netherlands and has been proven effective in reducing seizures (FMS).
Alzheimer’s. Studies have shown that people with Alzheimer’s who follow a ketogenic diet often experience improvements in memory and language skills (Jensen, 2020).
Parkinson’s. A small study with five participants showed that people with Parkinson’s had fewer symptoms after just 28 days on a ketogenic diet. Symptoms improved by about 45% (Vanitallie, 2005).

The diet not only helps reduce symptoms of these conditions but can also improve cognitive functions. A review study of 27 studies found that ketosis (the state that is caused by the ketogenic diet) improved thinking skills such as attention, memory, and alertness in most participants. Importantly, none of these studies found negative effects on brain function (Chinna-Meyyappan, 2023).

NTR science broadcast: The keto diet as medicine for ADHD and epilepsy with Eline Dekeyster

7. The ketogenic diet and the possible impact on ADHD

What is the evidence that the ketogenic diet can be beneficial for people with ADHD? This evidence is still scarce and recent. There are no randomized studies that show that people with ADHD benefit from this diet (or not). Yet more and more unpublished anecdotal reports point to a possible positive effect. Additionally, mechanistic evidence suggests that the ketogenic diet can help. These mechanisms involve the brain’s energy supply, protection against stress in brain cells, and the balance of neurotransmitters:\

7.1. Addressing brain energy deficits

As described earlier, ADHD is associated with a shortage of brain energy, particularly in areas essential for executive functions, attention regulation, and cognitive endurance (Todd, 2001). Research shows that the prefrontal cortex, an important brain area for these functions, uses less glucose in people with ADHD (Zametkin, 1990).

Ketones could provide a more efficient and stable energy source than glucose. Unlike glucose, which depends on food intake and fluctuates, ketones provide a constant energy supply. Ketones improve the functioning of mitochondria (the energy factories in cells) and increase energy production, which can contribute to improved energy supply in the brain in ADHD (Marosi, 2016).

7.2. Protection of brain cells

ADHD is associated with increased oxidative stress and low-grade inflammation. Oxidative stress occurs when harmful molecules, so-called reactive oxygen species (ROS), accumulate faster than the body can neutralize them. This can damage brain cells and impair their function. Research suggests that oxidative stress may play an important role in ADHD (Corona, 2020).

Ketones have a protective effect on neurons, meaning that they help protect brain cells against damage. They reduce inflammation and oxidative stress, which may possibly be beneficial for people with ADHD (Pinto, 2018).

7.3. Balancing neurotransmitters

People with ADHD often have an imbalance in important neurotransmitters, such as dopamine, norepinephrine, and glutamate (Cortese, 2012). These chemicals play a crucial role in focus, hyperactivity, and self-control.

Ketones seem to influence these chemicals in various ways. For example, they can increase the amount of GABA, a calming neurotransmitter that balances the excitatory effects of glutamate. By restoring this balance, ketones may possibly reduce hyperactivity, improve focus, and support emotional regulation in people with ADHD.

Although these initial findings are promising, more research is needed to determine whether these benefits can be consistently reproduced in people with ADHD.

8. Is the ketogenic diet safe?

To answer this question, we distinguish between children and adults.

8.1. Children

The ketogenic diet has been used for more than a century as a treatment for children with epilepsy who do not respond to medication. In the Netherlands, it is officially recognized as a treatment method for these cases. Usually, the diet is followed for about two years, or shorter if the seizures stop (Federation of Medical Specialists, 2024). For epilepsy, this duration is considered safe under medical supervision, but for other conditions, including ADHD, further research is needed into the long-term effects and safety. Long-term use can, for example, lead to growth delays.

8.2. Adults

For adults, the ketogenic diet is generally safe, provided they are under the guidance of a nutritionist to prevent nutritional deficiencies, electrolyte problems, and digestive complaints.

However, there are situations where caution is advised. People with rare metabolic disorders who cannot process fat well should avoid this diet. Additionally, adults who use certain medications should be extra careful. For example, people who use insulin for diabetes or lithium for bipolar disorder may find that the diet affects their treatment. In such cases, medical supervision is essential.

Finally, the diet can lead to an increase in LDL cholesterol, also called “bad” cholesterol. Higher LDL levels are associated with heart disease, so people following the diet should regularly check their cholesterol levels.

Box: ketoacidosis

The ketogenic diet sometimes raises concerns about ketoacidosis, but this is a misunderstanding. Ketosis, the desired state with the diet, and ketoacidosis, a dangerous medical condition, work via different mechanisms:
— Ketosis occurs when the body burns fat instead of carbohydrates, producing ketones as fuel. This process is natural and safe for most people.
— Ketoacidosis on the other hand is a dangerous condition where ketone levels become extremely high, leading to a harmful drop in the acidity of the blood (acidosis). This usually happens in people with untreated type 1 diabetes. For people with a healthy pancreas, the ketogenic diet does not cause ketoacidosis (Westerberg, 2013).

9. Starting with the ketogenic diet

This article does not cover all the details of the ketogenic diet. For more practical information, you can visit: the ultimate keto guide for beginners. This guide contains:

What a ketogenic diet is
How it works and what the effects on the body are
Explanation of ketosis and ketones and how to measure them
Information about nutrients
Which foods are suitable for the ketogenic diet
Recipes and meal plans

The ultimate keto guide for beginners

10. Conclusion

There is increasing evidence that the ketogenic diet can be beneficial for brain disorders such as Alzheimer’s and Parkinson’s.

For ADHD, the evidence is still limited to small studies and case reports, while large-scale clinical studies are lacking. Yet studies point to promising mechanisms, such as improved energy supply in the brain, a better neurotransmitter balance, and less inflammation.

When standard treatments for ADHD do not have sufficient effect, the ketogenic diet can be considered as an alternative, but medical supervision is recommended.

NTR broadcast about ketogenic diet and brain disorders

Veelgestelde vragen

Is the ketogenic diet proven effective for ADHD?

Direct evidence for ADHD is still limited. There are no randomized studies, but mechanistic evidence points to possible benefits via improved brain energy, reduced oxidative stress, and better neurotransmitter balance. The diet is proven effective for other brain disorders such as epilepsy.

Is the ketogenic diet safe for people with ADHD?

For adults, the ketogenic diet is generally safe under the guidance of a nutritionist. People with rare metabolic disorders, or who use certain medications such as insulin or lithium, should be extra careful. Regular cholesterol monitoring is recommended.

How can the ketogenic diet help with ADHD symptoms?

The diet can help through three mechanisms: (1) ketones provide an alternative, more stable energy source for the brain, (2) ketones protect brain cells against oxidative stress, and (3) ketones can improve the balance of neurotransmitters by increasing GABA.

Can I stop ADHD medication if I follow the ketogenic diet?

Never stop medication on your own. The ketogenic diet can be a supplement but does not replace medical treatment. Always discuss changes in your treatment plan with your doctor, especially if you use medications that may interact with the diet.

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