Bipolar and the keto diet Q&A

Professor Daniel Smith, Chair of Psychiatry and Head of Division of Psychiatry at the University of Edinburgh, answers your questions about bipolar and the keto diet.

What is the keto diet?

The keto diet (also known as the ketogenic diet) is a high-fat, low-carbohydrate eating plan that’s designed to shift the body’s metabolism from burning carbohydrates to burning fats. This process is known as ketosis. By drastically reducing carb intake, the body begins to turn fats into ketones, which become the main source of energy.

What do people eat when they’re on the keto diet?

People on the keto diet typically eat:

70-80% healthy fats (such as avocados, nuts, seeds, olive oil and fatty fish)
20-25% protein (such as eggs, chicken or beef)
5-10% carbs

This means they cut out most bread, pasta, rice and sugary foods and only have a limited intake of higher-carb fruits, starchy vegetables (eg potatoes) and wholegrains. However, low-carb vegetables like leafy greens, broccoli and peppers are commonly included.

Dairy products, such as cheese, butter and full-fat yoghurt, can also be included as part of a keto diet.

What are the benefits of the keto diet?

The keto diet has been shown to aid in weight loss, improve energy levels and possibly enhance mental clarity.

What are the downsides of the keto diet?

The keto diet is quite restrictive, making it difficult to follow long-term for some people (and potentially leading to nutrient deficiencies if it’s not well-balanced). Socially, the diet can mean that eating out, travelling or sharing meals can become more challenging.

In the first few weeks, some people experience the ‘keto flu’, which can cause headaches, fatigue, nausea and dizziness as the body adjusts to burning fat for fuel instead of carbs. It can also take time for the body to efficiently produce and use ketones.

Some people on the keto diet report bad breath due to the breakdown of ketones. The lack of fibre from wholegrains and some fruits can lead to digestive problems like constipation. Also a high-fat intake may cause stomach discomfort and, in some people, make conditions like leaky gut (where typical symptoms are bloating, excess gas and cramps) worse.

The keto diet can also lead to electrolyte imbalances and dehydration, as the body loses more water and essential minerals. In some people, particularly anyone living with kidney issues, the high intake of dietary fat and protein may put additional strain on the kidneys.

Additionally, while some people see improvements in heart health, others experience a rise in LDL (‘bad’) cholesterol due to increased saturated fat intake.

Can the keto diet help to manage bipolar symptoms?

There is research happening at the moment into how the ketogenic diet may help to manage bipolar symptoms, due to its impact on brain metabolism and neurochemistry.

By shifting the body’s energy source from carbohydrates to fats, the keto diet promotes the production of ketones. These are chemicals produced by the liver when the body is in a metabolic state known as ‘ketosis’ where it is breaking down fats for energy instead of using glucose.

Some research suggests ketones may influence neurotransmitter activity and reduce brain inflammation which could help stabilise mood in people with bipolar.

Neurotransmitters are chemical messengers in the brain, which send signals between nerve cells (neurons) – a process that’s crucial for various brain functions, including mood regulation, cognition and muscle control.

However, it is essential that people with bipolar speak to their doctor before starting a keto diet to ensure it won’t affect their current treatment plan.

Are there any risks in following a keto diet for people with bipolar?

Yes. While there is no clear evidence that the keto diet directly causes manic or depressive episodes in people with bipolar, it is thought it could potentially trigger mood fluctuations in some individuals, particularly during the initial phase when the body is adjusting to ketosis.

The process of transitioning from burning carbohydrates to burning fat for fuel can affect energy levels, sleep patterns, and overall mood stability. Some people may experience irritability, fatigue, or anxiety during this adjustment, which could mimic or worsen symptoms of mania or depression.

Some people find the lack of variety in the diet challenging, which could trigger stress and potentially impact mood.

Additionally, if the diet isn’t properly balanced, eating a limited number of foods could lead to nutrient deficiencies (such as magnesium, potassium, and vitamins A and C, which are commonly found in carbohydrate-rich foods), affecting overall health and mental wellbeing.

Is there any research on the keto diet and bipolar?

Some studies and anecdotal evidence show that the keto diet could work alongside traditional treatments to help manage bipolar. For example:

In our 2024 study at the University of Edinburgh, we looked at how a ketogenic diet might affect people with bipolar. Most participants were able to stick with the diet and about one third reported feeling more stable and having more energy. From the perspective of bipolar, this suggests that the ketogenic diet might have a positive impact on mood stability and overall wellbeing. There were some side effects, like tiredness and constipation, and one person had a serious reaction due to their medication.
A systematic review by Baastrup et al. (2018) examined the ketogenic diet's impact on psychiatric disorders, noting that while conclusive evidence for bipolar is limited, the diet may offer mood stabilisation, especially for treatment-resistant cases.
Freeman et al. (2000) and Stafstrom and Rho (2012), focused on the benefits of the keto diet in epilepsy, but highlighted potential neuroprotective effects that could translate to mood stabilisation in conditions like bipolar disorder.
Natan and Turel (2017) explored the mechanisms by which the keto diet could influence brain function and psychiatric conditions, suggesting that ketosis might promote neurochemical balance and reduce brain inflammation, factors implicated in mood regulation.

However, more research is needed to fully understand the effectiveness of the keto diet.

Can the keto diet help manage other conditions other than bipolar?

The ketogenic (keto) is commonly used to help obesity, as it shifts the body from burning carbohydrates to burning fat, which can lead to significant fat loss. The diet may also help to improve blood sugar control, making it beneficial for people with type 2 diabetes or insulin resistance by stabilising blood sugar levels and enhancing insulin sensitivity.

Some studies suggest the keto diet can improve heart health by lowering bad cholesterol (LDL) and triglycerides while raising good cholesterol (HDL).

The keto diet has also been shown in some studies to reduce the frequency of seizures in people living with epilepsy, particularly where anti-seizure medications haven’t been effective. It has been used for many years to treat epilepsy in children who do not respond to anticonvulsants.

Early research may also indicate that the keto diet has neuroprotective effects which could benefit individuals with neurological conditions like Alzheimer's and Parkinson's disease.

Does the keto diet interact with common bipolar medications, such as lithium?

The high-fat, low-carb nature of the keto diet may change the absorption and metabolism of certain medications, potentially affecting their effectiveness. The impact is greater on medications which are fat-soluble drugs and/or processed by the liver, such as lithium and other mood stabilisers, and antipsychotics.

The keto diet has a diuretic effect where the body produces and passes more urine. This can lead to dehydration. The diet can also lead to the imbalance of minerals in the body (eg. sodium, potassium, calcium, magnesium) that are essential for various bodily functions, including maintaining fluid balance, transmitting nerve signals, and contracting muscles.

This change in sodium and hydration levels may increase the risk of lithium toxicity, so people are recommended to ensure a good daily intake of water.

What should someone with bipolar consider before starting the keto diet?

To manage the potential risks, anyone considering starting the keto diet must:

speak to a doctor before starting the diet
monitor hydration and electrolyte intake carefully
have regular blood tests to track medication levels and overall health

Want to talk through the pros and cons of a keto diet? Call us on 0333 323 3880, or email [email protected]