In this article, we discuss new evidence on how this diet may offer potential benefits for people with ADHD.
Author: Jaap Versfelt.
Scientific reviewers: Nathalie van Vugt, MSc, LBI alumnus; David Bezpalec, PhD candidate at LBI; Dr. Eline Dekeyster, Assistant Professor of Neuroscience and Head of the LBI Research Group. LBI (Lifestyle Brain Interaction), Leiden University.
Key insights from this article
- ADHD overview: ADHD is a condition that causes difficulties with attention, hyperactivity, and impulsive behavior. There is a sevenfold increase in ADHD medication use in the Netherlands since 2002.
- Brain energy shortages in ADHD: The brain uses a lot of energy, mostly from glucose, derived from sugars and starches in food. However, in people with ADHD, the brain doesn’t always use glucose efficiently. The insufficient supply of energy to the brain might be responsible for some of the cognitive impairments seen in ADHD.
- Role of metabolic dysfunction: Metabolic dysfunction happens when the body struggles to convert food into energy efficiently. Metabolic dysfunction is more common in people with ADHD. Metabolic dysfunction is linked to lifestyle factors like poor diet and lack of exercise.
- Might the ketogenic diet be a solution? The ketogenic diet contains a lot of fats and few carbohydrates. This forces the body to use “ketones,” a different type of fuel made from fat, instead of glucose. Ketones thereby provide an alternative energy source for the brain.
- Evidence for ketogenic diet: The ketogenic diet is part of the standard of care for epilepsy and shows promise for Alzheimer’s, Parkinson’s, and cognitive improvements. While direct evidence for ADHD is limited, mechanisms like improved energy metabolism and reduced neuroinflammation suggest potential benefits.
- Safety considerations: The ketogenic diet is generally safe for adults. Certain preconditions should be excluded, such as certain rare metabolic disorders, certain medications (e.g., insulin, lithium) and eating disorders. Cholesterol levels should be monitored frequently when you adhere to ketogenic diet. For children, the diet is part of the standard treatment for epilepsy, albeit for a limited period (two years), while guidelines for other disorders are not available. Medical supervision is therefore advised before embarking on this diet.
- Starting the diet: Starting a ketogenic diet can be challenging without guidance. Resources like beginner guides and meal plans can make the transition easier.
- Conclusion: Although more research is needed, the ketogenic diet offers a potential alternative for managing ADHD symptoms, especially when standard treatments don’t work well.
1. ADHD overview
ADHD stands for attention deficit hyperactivity disorder. It’s a condition that affects how people focus, manage tasks, and control their impulses. ADHD can show up as one or more of the following behaviors:
- Inattention: This means struggling to stay focused, getting distracted easily, or having trouble staying organized.
- Hyperactivity: This includes being constantly on the move, feeling restless, or talking a lot – even when it’s not the right time.
- Impulsivity: Acting without thinking, interrupting others, or finding it hard to wait your turn.
Everyone experiences some of these behaviors occasionally. What makes ADHD different is that these behaviors happen frequently and in different settings—like at school, at work, at home, or with friends. They also interfere with daily life and responsibilities.
2. ADHD prevalence is increasing
More children are being diagnosed with ADHD now than in the past. In 2023, over 5% of Dutch parents said their child, aged 4 to 12, has ADHD. Boys are more often diagnosed than girls—about 6.6% of boys compared to 3.5% of girls (NJI, 2024).
The number of people using medication for ADHD has also risen sharply. In 2002, around 40,000 people in the Netherlands were prescribed ADHD medication like Ritalin. By 2023, that number had grown to 282,000 (SFK, 2023). See figure 1.
Figuur 1. Ontwikkeling gebruik ADHD-medicatie in Nederland (GIP, 2023)
What could be the cause of this increase and what can be done about it? To explore these questions, we first need to understand how the brain uses energy and what happens when this process doesn’t work properly.
3. The brain as energy-intensive organ
The human brain is incredibly demanding when it comes to energy. Even though it only makes up about 2% of body weight, it uses around 20% of the body’s energy at rest. This energy mainly comes from glucose, a type of sugar found in food. After eating, carbohydrates—like bread, pasta, and rice—are broken down into glucose, which is then delivered to the brain through the blood. Glucose is the brain’s primary fuel.
However, the brain’s dependence on glucose has a downside. If something disrupts how glucose is used, the brain may not get the energy it needs to function properly. This is especially important to consider for people with ADHD.
- ADHD affects how people focus, plan, and manage tasks. These cognitive activities rely on parts of the brain that need a lot of energy to work well. Research has shown that when people perform complex mental tasks, the parts of the brain responsible for those tasks require more energy. If the brain doesn’t get enough energy, these tasks become harder to complete.
- Cognitive tasks require brain energy. In people with ADHD, scientists have found that some parts of the brain – particularly those involved in focus and decision-making – use glucose less efficiently. This reduced ability to use glucose for energy is called “cerebral glucose hypometabolism” and has been observed in several brain-related conditions, including ADHD (Newman, 2011).
- Brain energy availability can be disrupted for people with ADHD. A reduced ability to use glucose as an energy source is seen in various neurological disorders like epilepsy, traumatic brain injury, bipolar disorder, Alzheimer’s disease. And also for ADHD (Zametkin, 1990). This energy shortage could explain some of the challenges faced by people with ADHD.
What could cause such shortages of energy in the brain?
4. Metabolic disfunction disrupts the use of glucose for energy in the brain
Metabolic dysfunction occurs when the body’s metabolism – the system that turns food into energy and supports growth – does not work properly. This can interfere with how the brain gets its energy. Normally, the brain depends on glucose, a type of sugar from food, as its main energy source. Glucose is carried in the blood and enters cells with the help of insulin, a hormone that acts like a “key” to unlock the cells so glucose can get in.
When metabolic dysfunction occurs, the 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 struggles to get enough energy.
Metabolic dysfunction increases the risk of physical conditions such as type 2 diabetes, myocardial infarctions, and strokes. Additionally, metabolic dysfunction raises the risk of brain disorders like dementia and Parkinson’s disease. Likewise metabolic syndrome (the clinical manifestation of metabolic dysfunction) is associated with ADHD (Yuan, 2022).
The link between metabolic dysfunction and ADHD is still being explored. This relationship may be bidirectional – metabolic dysfunction could increase the risk of ADHD, while ADHD may lead to lifestyle choices that contribute to metabolic dysfunction.
Metabolic dysfunction is increasingly common in the Netherlands. In the 1990s 19 percent of men and 12 percent of women aged 28 to 59 were diagnosed with metabolic syndrome. By 2020, this had doubled to 36 percent of men and 24 percent of women (Bos, 2007, Sigit, 2020).
Metabolic dysfunction is influenced by lifestyle factors such as eating a lot of ultra-processed food, lack of exercise, stress, insufficient sleep, and exposure to harmful substances. Improving these habits can help restore the body’s ability to use glucose for energy, which supports both physical and brain health.
5. Ketones as an alternative fuel for the brain
The ketogenic diet is a way of eating that is high in fat and very low in carbohydrates. It causes the body to enter a state called ‘ketosis’, where it switches from using carbohydrates as its main energy source to using ‘ketones’.
Ketones are special molecules made in the liver when the body breaks down fat. Normally, the brain relies on glucose (a type of sugar) from carbohydrates for energy. 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 travel through the bloodstream to the brain, where they provide energy.
Remarkably, after a very long fasting period (30 to 40 days) ketones can meet up to 70% of the brain’s energy. The body still makes some glucose for the brain through a process called ‘gluconeogenesis’. In this process, glucose is created from non-carbohydrate sources like proteins found in foods such as meat, eggs, or beans.
This ability to use ketones as an energy source is a survival mechanism from human evolution. During times when food was scarce, the body relied on fat stores to produce ketones, ensuring the brain could keep functioning even without regular meals. This adaptation allowed people to 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 way to help with brain-related conditions (Anderson ,2025). It is already widely used to treat type 2 diabetes, as it can improve blood sugar levels and help the body use insulin better (Goldenberg, 2021). But how does it affect the brain? Research shows it can also help with several brain disorders. Here are some examples:
- Epilepsy. For over 100 years, the ketogenic diet has been used to treat epilepsy, especially in people whose seizures do not improve with medication (Jiang, 2022). In children, it is even part of official medical guidelines in the Netherlands and has been shown to reduce seizures effectively (FMS).
- Alzheimer’s. Studies have found that people with Alzheimer’s who follow a ketogenic diet often experience improvements in memory and language abilities (Jensen, 2020).
- Parkinson. A small study with five participants showed that people with Parkinson’s had fewer symptoms after following the ketogenic diet for just 28 days. Symptoms improved by around 45% (Vanitallie, 2005).
The diet not only helps reduce symptoms of these disorders but can also improve cognition. A review of 27 studies found that being in ketosis (the state created by following the ketogenic diet) improved thinking skills such as attention, memory, and alertness in most participants. Importantly, none of these studies found that the diet harmed brain function (Chinna-Meyyappan, 2023).
7. The ketogenic diet and its potential impact on ADHD
What is the evidence that the ketogenic diet might benefit people with ADHD? That evidence is still recent and scarce. There are no randomized trials showing that people with ADHD on such a diet benefit (or not). However, an increasing number of unpublished anecdotal reports indicate it could be effective. Next to that, mechanistic evidence suggests the ketogenic diet might help. These mechanisms involve the brain’s energy supply, protection from stress in brain cells, and balance of brain chemicals. Additionally, some research on the brain’s mechanisms suggests that the ketogenic diet might help by improving the brain’s energy supply, protecting brain cells from stress, and keeping brain chemicals in balance. While these early findings are promising, more research is needed to determine if these benefits can be consistently replicated in people with ADHD.
7.1 Addressing brain energy deficits
As we have written above, ADHD is linked to deficits in brain energy metabolism, particularly in regions critical for executive function, attention regulation, and cognitive endurance (Todd, 2001). Studies show that the prefrontal cortex, a brain area critical for these functions, show reduced usage of glucose in individuals with ADHD (Zametkin, 1990).
Ketones could offer a more efficient and stable energy source than glucose. Unlike glucose, which fluctuates with dietary intake, ketones provide a continuous energy supply. Ketones enhance mitochondrial function and increase ATP production in neurons, which may help improve brain energy supply in ADHD (Marosi, 2016). Combined this can improve brain energy supply in ADHD.
7.2 Protecting brain cells
ADHD is linked to increased oxidative stress and inflammation. Oxidative stress occurs when harmful molecules, called reactive oxygen species (ROS), build up faster than the body can neutralize them. This can damage brain cells and impair their function. Research shows that oxidative stress may play a significant role in ADHD (Corona, 2020).
Ketones have a neuroprotective effects, meaning they help protect brain cells from damage. They reduce inflammation and oxidative stress. This protective effect could potentially benefit individuals with ADHD (Pinto, 2018).
7.3 Balancing neurotransmitters
People with ADHD often have imbalances in key neurotransmitters, such as dopamine, norepinephrine, and glutamate (Cortese, 2012). These chemicals play crucial roles in focus, hyperactivity, and self-control.
Ketones appear to influence these chemicals in several ways. For example, they can help increase GABA, a calming brain chemical that balances the excitatory effects of glutamate. By restoring this balance, ketones may help reduce hyperactivity, improve focus, and support emotional regulation in people with ADHD.
8. Is the ketogenic diet safe for people with ADHD?
To answer this question, we will distinguish between children and adults.
8.1. Children
The ketogenic diet has been used for over 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 for these cases. Typically, the diet is followed for about two years, or shorter if seizures stop (Federation of Medical Specialists, 2024). For epilepsy, this duration is considered safe under medical supervision, but for other conditions, including ADHD, long-term effects and safety require further research. Prolonged use may lead to complications such as growth delays.
8.2. Adults
For adults, the ketogenic diet is generally safe if they are guided by a nutritionist to avoid nutritional deficiencies, electrolyte imbalances and gastrointestinal issues. However, there are some situations where caution is necessary. People with rare metabolic disorders that make it hard to process fat should not follow this diet.
Additionally, adults who take certain medications need to be careful. For example, people using insulin for diabetes or lithium for bipolar disorder may find that the diet interacts with their treatment. In such cases, a doctor should be involved in planning the diet. This is especially important for people with psychological or medical conditions.
Lastly, the diet can cause an increase in LDL cholesterol, sometimes called “bad cholesterol.” Higher levels of LDL cholesterol are linked to heart disease, so people following the diet should monitor their cholesterol levels regularly.
Kader: Ketoacidosis
The ketogenic diet sometimes raises concerns about ketoacidosis, but this is a misunderstanding. Ketosis, the state induced by the diet, and ketoacidosis are two different things. Ketosis, the intended effect of the diet, and ketoacidosis, a dangerous medical condition, operate through different mechanisms:
– Ketosis happens when the body burns fat instead of carbohydrates for energy, producing ketones as fuel. Ketosis occurs when the body shifts to burning fat for energy instead of carbohydrates, producing ketones as a fuel source. This process is natural and safe for most people.
– Ketoacidosis is a dangerous condition that occurs when ketone levels become extremely high, causing a harmful drop in blood pH (acidosis). This happens when insulin is critically low or absent, leading to dangerously high blood sugar levels. Ketoacidosis is most common 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 cannot cover the ketogenic diet in full detail. However, those interested in learning more can find practical information here: ‘De ultieme keto-gids voor beginners‘. This guide contains:
- What a ketogenic diet is
- How it works and why it affects the body
- An explanation of ketosis and ketones and measuring these ketones
- Information on nutrients
- Which foods fit the ketogenic diet
- Recipes and meal plans
10. Conclusion
There is increasing evidence that a ketogenic diet can also benefit people with brain disorders like Alzheimer’s and Parkinson.
For ADHD, the evidence is still limited to smaller studies and case reports, while randomised clinical studies are still lacking. However, research points to promising mechanisms through which a ketogenic diet could address challenges often seen in ADHD, such as reduced energy metabolism in the brain, imbalances in neurotransmitters like dopamine, and inflammation.
When standard ADHD treatments do not achieve satisfactory results, a ketogenic diet could be explored as an alternative approach. Medical supervision is advised before embarking on this diet.
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