RecruitingInterventional

Comparison of a ketogenic diet and NHS healthy eating guidance for bipolar depression: a randomised controlled trial

Bipolar depression can be difficult to manage, and standard medications do not work well for everyone. Researchers at the University of Edinburgh and NHS Lothian are running a study called ENERGISE-BD to find out if changing your diet could help relieve low mood in bipolar disorder. The study compares two ways of eating over 12 weeks: the low-carbohydrate, high-fat 'keto' diet, and the standard NHS Eatwell balanced diet. In total, 206 adults with bipolar depression will take part. Participants will be put into one of the two diet groups by chance. Throughout the study, the research team will check your mood, general health, and blood markers. Taking part will help doctors understand whether specific diets could become a helpful add-on treatment for bipolar depression in the NHS.

At a glance

Status

Recruiting

Sponsor

University of Edinburgh and NHS Lothian

Enrolment target

206

Start

14 Oct 2026

Estimated completion

01 Dec 2029

Bipolar depression

What is this study about?

Bipolar disorder is a lifelong mental health condition marked by shifts in mood, energy, and activity levels. For many people, the depressive phases can be persistent and difficult to treat. While medications and talking therapies are available, they do not work for everyone and can sometimes cause unwanted side effects. Because of this, scientists are keen to explore safe, practical lifestyle treatments that might support mental health.

There is growing scientific interest in how the food we eat affects our brain chemistry. When a person follows a ketogenic (or 'keto') diet, they eat very few carbohydrates and a higher amount of healthy fats. This shifts the body from using sugar for energy to burning fat, producing compounds called ketones. Scientists think ketones may change how brain cells produce energy and communicate, potentially lifting low mood. However, we do not yet know if a keto diet works better than standard healthy eating.

This trial compares the keto diet directly against the NHS Eatwell Guide, which promotes a balanced mix of fruit, vegetables, starchy carbohydrates, and protein. By comparing the two groups over several weeks, the researchers hope to discover whether one diet offers clear benefits for bipolar depression. The findings could give doctors and patients new, evidence-based ways to manage symptoms in the future.

Key takeaways

The ENERGISE-BD trial compares a keto diet to NHS healthy eating guidelines for bipolar depression.
Participants follow their assigned diet for 12 weeks, with overall study monitoring lasting 24 weeks.
The study involves 3 to 4 clinic appointments, regular mood surveys, and routine health checks.
You will receive personal guidance from a qualified dietitian throughout your diet plan.
Joining is completely voluntary, and you can stop taking part at any time.

Who may be eligible?

This study is open to adults aged 18 and over who have an official diagnosis of bipolar disorder (either type 1 or type 2) and are currently experiencing symptoms of depression of at least moderate severity. To take part, you will need a smartphone so you can use a health-tracking app during the trial.

You cannot join the study if you need urgent mental health crisis support, or if you have already followed a strict keto diet within the last two months. People who are currently taking weight-loss medications (such as Ozempic or Wegovy), or those who follow an exclusively vegan or plant-based diet, are also not eligible.

Because the keto diet places specific demands on the body, people with certain physical health conditions cannot take part for safety reasons. This includes people who are pregnant or breastfeeding, people with type 1 diabetes, heart conditions, liver or kidney disease, or a history of eating disorders such as anorexia or bulimia.

Could this study suit you?

Answer these quick questions to see if you may be eligible. This is a guide only — the research team makes the final call.

Are you aged 18 or older with a diagnosis of bipolar disorder?
Are you currently experiencing moderate or severe low mood (depression)?
Do you have a smartphone that can run health apps?
Are you free from major kidney, liver, or heart conditions, and not pregnant?
Are you willing to be placed into either diet group by chance?

Answer every question to see your result.

What does participation involve?

Taking part in the study lasts for 24 weeks in total. For the first 12 weeks, you will follow your assigned diet programme—either the ketogenic diet or the NHS Eatwell Guide. A computer will place you into one of the two groups at random, and you will have support from a qualified dietitian to help you understand and stick to the meals.

You will need to attend 3 or 4 face-to-face appointments with the research team. At these visits, staff will measure your height, weight, and blood pressure. You will also give blood and urine samples to check your general health, blood sugar, and ketone levels. In addition, you will complete questionnaires about your mood and everyday life. A small group of participants in Edinburgh may also be invited to have a painless magnetic resonance brain scan to see how brain chemistry responds to the diet.

Potential risks and benefits

You may benefit from receiving personal dietary guidance from a dietitian and learning more about how food relates to your mood. Your participation could also help shape future NHS treatments for bipolar depression. However, changing your diet can cause temporary side effects such as nausea, constipation, tiredness, headaches, or hunger. Blood tests can cause mild discomfort or bruising, and brain scans may feel uncomfortable if you dislike enclosed spaces. Some questionnaire topics are personal and could feel upsetting. Taking part is completely voluntary, and you are free to leave the study at any point without it affecting your usual NHS medical care.

Locations (2)

Royal Infirmary of Edinburgh at Little France
City only
Lothian, Scotland
The Barberry
Approximate
Birmingham, England

Common questions

Can I choose which diet group I am in?

No. A computer assigns you to either the keto diet or the NHS Eatwell diet by chance, giving each person an equal 50/50 opportunity. This ensures the results are fair and reliable.

Do I have to stop taking my regular bipolar medication?

No. This study looks at diet alongside your regular care. You should never stop or change your prescribed medications without speaking to your doctor.

Will taking part cost me anything?

No. Taking part is free, and the study team will reimburse you for your travel costs and your time at study visits.

What happens if I struggle to follow the diet?

You will have support from a qualified dietitian throughout the 12 weeks to answer your questions, share meal ideas, and help you manage any challenges.

Can I leave the study if I change my mind?

Yes. You can withdraw from the study at any time, for any reason, and your normal healthcare will not be affected in any way.

How to find out more

Lorna Dewar

energise-bd.trial@ed.ac.uk - Official trial record

Always speak to your GP or specialist before deciding to take part in a study.