Most people have heard of the high fat, low carb “keto” diet that is often followed for weight loss and for improving blood sugar, but a therapeutic ketogenic diet is very different. Therapeutic ketogenic diets have been used for more than 100 years in the treatment of epilepsy and diabetes and more recently, in the treatment of various mental health disorders, including depression, bipolar disorder, and schizophrenia.
A research article published on July 6, 2022 in Frontiers of Psychiatry was my first exposure to the use of a therapeutic ketogenic diet in the treatment of mental health disorders. This was of great interest to me because my graduate research was in the area of mental health nutrition, and for the last 5 years I have supported people following therapeutic ketogenic diets for seizure disorder, and as adjunct treatment in specific forms of cancer. The use of a therapeutic ketogenic diet in mental health brings these two formerly separate areas of my experience together.
In this pilot study, thirty one adults in a psychiatric hospital in Toulouse, France who had treatment-resistant depression, bipolar disorder, and schizoaffective disorder were placed on a therapeutic ketogenic diet that restricted their carbohydrate intake to 20g per day. Of the 28 patients that followed the diet for longer than two weeks, symptoms of depression and psychosis improved in all 28 patients, with improvements becoming noticeable within three weeks or less. Most impressive was that 43% of patients achieved clinical remission of symptoms, and 64% were discharged from the hospital on less psychiatric medication .
The release of the best-selling book Brain Energy in mid-November 2022, written by Harvard psychiatrist Dr. Chris Palmer, one of the pioneers in the use of a therapeutic ketogenic diet in treating psychiatric disorders [2,3,4], brought the use of this type of diet in mental health to public awareness. As a result of the book, I have had many more individuals contact me about designing such a diet to see if it would improve their mental health.
But what is a therapeutic ketogenic diet?
Types of Therapeutic Ketogenic Diets
There are several types of therapeutic ketogenic diets, each designed according to a specific “ketogenic ratio” which specifies the amount of fat in the diet compared to the total amount of protein plus carbohydrate.
Classic Ketogenic Diet (KD)
The Classic Ketogenic Diet uses a 4:1 ratio which means it is made up of 4 grams of fat for every 1 gram of protein plus carbohydrate. That is, for every 5 grams of food eaten, there are 4 grams of fat and 1 gram of protein and/or carbohydrate. A 4:1 ketogenic diet contains 80% fat (4÷5=80%) and 20% protein plus carbohydrate (1÷5=20%), and protein may be set at 15% of calories with a maximum of 5% of calories coming from carbohydrate, or protein may be set lower at 10%, and carbohydrate as high as 10%. This type of diet may be used when the need to achieve and maintain high levels of ketones is necessary.
It is important to note that the ketogenic ratio compares the amount of fat, protein, and carbohydrates in grams, which is a measure of weight. The diet is calculated in grams, since food is measured by weight, in grams.
As you will see below, the amount of fat, protein and carbohydrate in the diet can also be calculated as a percentage of calories.
Modified Ketogenic Diet (MKD)
The Modified Ketogenic Diet uses a 3:1 ratio which means it is made up of 3 grams of fat for every 1 gram of protein plus carbohydrate. For every 4 grams of food eaten, there are 3 grams of fat and 1 gram of protein and carbohydrate. A 3:1 ketogenic diet contains 75% fat (3÷4=75%) and 25% protein plus carbohydrate (1÷4=25%). Some psychiatrists will start their patients on a 3:1 therapeutic ketogenic diet and once their patient is producing significant levels of ketones and is stable with respect to symptoms, may gradually have them transition over to a Modified Atkins Diet (see below) while monitoring their symptoms.
Modified Atkins Diet (MAD)
The Modified Atkins Diet uses a 2:1 ratio and is often used when people are taking a break from a 4:1 or 3:1 therapeutic ketogenic diet, and is also used as a therapeutic diet in mental health as it is the easiest for people to sustain long term. As mentioned above, some psychiatrists will start their patients on a 3:1 ketogenic diet to generate higher levels of ketones and then gradually have their clients transition over to a Modified Atkins Diet as it is more sustainable long term. This diet is also very helpful for those who do not tolerate the very high fat content of a 4:1 or 3:1 diet. In a Modified Atkins Diet, for every 3 grams of food eaten, there are 2 grams of fat and 1 gram of protein and carbohydrate. A 2:1 ketogenic diet contains 67% fat (2÷3=67%) and 33% protein plus carbohydrate (1÷3=25%).
Calculating Ratios Based on a Percentage of Calories
The first step for me, as a Dietitian in designing a therapeutic ketogenic diet is to determine the amount of calories (kcals) a person requires. This is routine work in designing any Meal Plan.
The next step is unique to the design of therapeutic ketogenic diets and that is calculating the specific percent of calories that needs to come from fat, protein and carbohydrate.
It is important to note that calculating the ratio provided from fat, protein and carbohydrate based on calories arrives at a different percentage than when calculating the ratio based on grams of food. This is because fat provides more calories per gram (9 kcal/g) than protein and carbohydrates (4 kcal/g).
To get 500 calories as protein, one would need to eat 125g of protein (500÷4=125), but to get the same 500 calories as fat, one would only need to eat 55.5 g of fat (500÷=55.5), because fat is much more calorically dense. Therapeutic ketogenic diets have much smaller meals because fat provides the same number of calories, for much less mass (weight, in grams).
Classic Ketogenic Diet – 90% fat as a percentage of calories
On a 4:1 ketogenic diet, 90% of the calories in the diet comes from fat when measuring by calories (80% fat if you are measuring by weight, in grams). This can be confusing, but remember that a 4:1 ketogenic ratio represents 4 grams of fat for every 1 gram of carbohydrate plus protein.
- Four grams of fat (which provides 9 calories per gram) provides a total of 36 calories (4 x 9 = 36).
- One gram of protein or carbohydrate (which provides 4 calories per gram) provides a total of 4 calories (1 x 4 = 4).
That is, the ratio of calories from fat to calories from protein plus carbohydrate is 36:4. This means that for every 40 calories consumed, 36 calories come from fat and 4 calories come from protein and/or carbohydrate. Thus, 90% of the calories comes from fat (36÷40=90%), and 10% comes from protein and carbohydrate (4÷40=10%) .
Modified Ketogenic Diet (MKD) – 87% fat as a percentage of calories
On a 3:1 ketogenic diet, about 87% of the calories comes from fat, and 13% comes from protein plus carbohydrate.
- Three grams of fat (which provides 9 calories per gram) provides a total of 36 calories (3 x 9 = 27).
- One gram of protein or carbohydrate (which provides 4 calories per gram) provides a total of 4 calories (1 x 4 = 4) .
On a Modified Ketogenic diet, the ratio of calories from fat to calories from protein plus carbohydrate is 27:4. This means that for every 31 calories consumed, 27 calories come from fat and 4 calories come from protein and/or carbohydrate. Thus, 90% of the calories comes from fat (27÷31=87%), and 13% comes from protein and carbohydrate (4÷31=13%) .
A Dietitian’s Role in Therapeutic Ketogenic Diets
In a recent Psychiatry and Psychotherapy podcast where Dr. Chris Palmer was interviewed, he talks about how Psychiatrists can incorporate use of a therapeutic ketogenic diet in their practice . The first thing he said was that there was a need for the physician to determine if this approach is appropriate for a specific patient. For people considering using a ketogenic diet as adjunct treatment to support their mental health, the first place to start is by having this discussion with your doctor.
[For those on some very specific types of medications, I will request for a note from people’s doctors (either their Psychiatrist or GP) to ensure that they are aware that their patient intends to follow a therapeutic ketogenic diet, and to ensure that they will be monitoring their patient’s health and medications, as they do.]
As outlined in a 2018 article titled “Don’t Try This at Home – when medical supervision is needed“, beginning a ketogenic diet is something that needs to be done with the knowledge and oversight of one’s doctor — especially when taking specific types of medication such as;
- insulin (or insulin analogues)
- medication to lower blood glucose such as sodium glucose co-transporter 2 (SGLT2) medication including Invokana, Forxiga, Xigduo, Jardiance, etc.,
- medication to control blood pressure such as Ramipril, Lasix (furosemide), Lisinopril / ACE inhibitors, Atenolol / βeta receptor antagonists, etc.,
- mental health medications such as antidepressants, medication for anxiety disorder, bipolar disorder (such as Lithium), and schizophrenia
Dr. Palmer recommends that doctors have their patients remain on their medication while starting a therapeutic ketogenic diet, and be evaluated during the stages of ketosis to see if there has been any significant change in symptoms .
[People who follow a therapeutic ketogenic diet for medical reasons are often asked to track their Glucose-Ketone Index (GKI) so their doctors can monitor the benefit of the diet. I teach people how to do that.]
Dr. Palmer suggests that individuals should trial a therapeutic ketogenic diet for a period of three months , and if the doctor finds that it is working well, they can begin to slowly taper off some medications. As mentioned in the “Don’t Try This at Home” article, changing dosages of medication is not something people should do on their own.
In the podcast, Dr. Palmer makes an important point. With the gradual decrease in medications, people must realize that they are more reliant on the ketogenic diet to keep symptoms under control. Since the ketogenic diet is therapeutic, taking “cheat days” is not an option. Dr. Palmer notes that it takes several days to get back into ketosis after breaking the diet and during this time, symptoms can dramatically reappear .
Dr. Palmer says that if a Psychiatrist is interested in beginning to use a therapeutic ketogenic diet in their clinical practice, they must be “well-informed on the science behind a therapeutic ketogenic diet, as well as metabolic functioning as a whole“.
Dr. Palmer recommends that doctors begin with the following first two steps :
Find a licensed dietician knowledgeable in therapeutic ketogenic diets and partner with them.
Read the book “Ketogenic Therapies” by Dr. Eric Kossoff
Dr. Eric Kossoff’s book, Ketogenic Diet Therapies for Epilepsy and Other Conditions is one that have referred to often over the last 5 years of designing therapeutic ketogenic diets in different applications.
Steps to Getting Started
If you are wondering if a therapeutic ketogenic may be worth trialing for improved mental health, then reach out to your doctor.
1. Have the MD determine if ketogenic diet may be appropriate for you.
2. If yes, the doctor can either recommend — or you can reach out to a Registered Dietitian knowledgeable in therapeutic ketogenic diets to partner with.
3. Understand that you will remain on your medication while implementing a ketogenic diet.
4. Be prepared for the commitment of trialing a ketogenic diet for 3 months, under your doctor’s supervision.
5. If after that time you are doing well and provided you are committed to remaining on the diet, your MD may consider slowly deprescribing some medications.
If you would like more information about having a therapeutic ketogenic diet designed for you, please send me a note using the Contact Me form at the top of this page.
To your good health!
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- Danan A, Westman EC, Saslow LR, Ede G. The Ketogenic Diet for Refractory Mental Illness: A Retrospective Analysis of 31 Inpatients. Frontiers in Psychiatry, 06 July 2022. https://doi.org/10.3389/fpsyt.2022.951376
- Palmer, C.M., J. Gilbert-Jaramillo, E.C. Westman. “The Ketogenic Diet and Remission of Psychotic Symptoms in Schizophrenia: Two Case Studies.” Schizophrenia Research. 2019 June; 208: 439-440, ISSN 0920-9964. https://doi.org/10.1016/j.schres.2019.03.019
- Sarnyai, Z, Palmer, C.M.,Ketogenic Therapy in Serious Mental Illness: Emerging Evidence, International Journal of Neuropsychopharmacology, Volume 23, Issue 7, July 2020, Pages 434–439, https://doi.org/10.1093/ijnp/pyaa036
- Norwitz, N., G.A. Dalai, S. Sethi; C. Palmer. “Ketogenic diet as a metabolic treatment for mental illness.” Current Opinion in Endocrinology & Diabetes and Obesity: 2020 Oct: 27(5): 269-274.
Eastman, M., KetoConnect, The Ketogenic Ratio Explained, September 16, 2014, https://www.myketocal.com/blog/the-ketogenic-ratio-explained/
- Dr. David Puder, MD, Psychiatry Podcast, Episode 163, Dr. Chris Palmer: Ketogenic Diet for Mental Health, M=November 15, 2022, https://www.psychiatrypodcast.com/psychiatry-psychotherapy-podcast/163-treating-mental-health-disorders-with-a-ketogenic-diet
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