A Keto Diet and a Therapeutic Ketogenic Diet are Very Different

This article was first written on June 17, 2024, and was updated on April 23, 2026

Practitioner’s Preface

Popularized ketogenic diets restrict carbohydrates primarily for weight loss or metabolic management without strict macronutrient tracking. In contrast, therapeutic ketogenic diets function as precise medical nutrition therapies that strictly control macronutrient ratios, weigh all ingredients, and monitor blood biomarkers to manage specific neurological, psychiatric, or oncological conditions.

With the release of several books outlining a role in mental health, therapeutic ketogenic diets have grown in popularity. Some people think they are the same as keto diets for weight loss or blood sugar control in type 2 diabetes. They are similar but very different.

How Are Therapeutic Ketogenic Diets Different from Keto Diets?

Popularized “keto” diets focus on carbohydrate restriction with variable protein allowances and little to no biochemical tracking. Therapeutic ketogenic diets are Medical Nutrition Therapy that require exact gram-weight measurements of all food components to achieve specific macronutrient ratios, altering cellular metabolism and achieving precise target ranges on the Glucose-to-Ketone Index.

A therapeutic ketogenic diet is used for ketogenic diet therapy (also called ketogenic metabolic therapy, a type of medical nutrition therapy). A doctor may prescribe it, or a Dietitian may implement it under a doctor’s supervision as part of treatment for mental or physical health.[1]

There is no single “keto diet.” Most keto diets restrict carbohydrates and offer different levels of protein. They usually do not require weighing food or checking blood sugar or ketones, though some people choose to. Therapeutic ketogenic diets tightly control protein and carbohydrate amounts relative to fat. Diet plans such as 4:1, 3:1, or 2:1 require weighing ingredients and monitoring blood glucose and ketones. [1]

Why do Therapeutic Ketogenic Diets Need to be Designed by an Experienced Dietitian?

Clinical implementation of therapeutic ketogenic protocols requires specialized experience in medical nutrition therapy across metabolic, psychiatric, and oncology domains. Ongoing evaluation of emerging peer-reviewed literature and structured diagnostic tools ensures these high-ratio dietary protocols are safely and effectively integrated alongside conventional medical treatments.

For the past 7 years of my almost 18 years in private clinical practice and licensure in British Columbia, Alberta, and Ontario, I have offered specialized services in designing therapeutic ketogenic diets for mental and physical health. Expanding my practice in this area was built on the previous 3 years of designing keto diets for metabolic health (weight loss, type 2 diabetes remission), in which I now have a decade of experience, along with updating my clinical knowledge by reading Kossoff’s Ketogenic Diet Therapies for Epilepsy and Other Conditions [1], as well as academic research papers where a therapeutic ketogenic diet was used clinically, and studying textbooks such as academic research papers where therapeutic ketogenic diets were used clinically, and of course, utlizing the clinical resources on the Charlie Foundation’s Ketogenic Diet Calculator. I continue to read emerging studies as they come out, including one that was published yesterday, April 21, 2026, in Frontiers in Oncology Cancer Metabolism about successfully using a therapeutic ketogenic diet as an adjunct treatment alongside chemotherapy in a 49-year-old woman with hormone receptor-positive (HR+) breast cancer [8], in which she remained in remission beyond 3 years.

What Medical Conditions May Benefit from a Therapeutic Ketogenic Diet?

Formulated over a century ago for epilepsy and diabetes, therapeutic ketogenic diets are increasingly utilized as clinical interventions in oncology and psychiatric medicine. These high-fat protocols alter systemic metabolism to reduce seizure activity, suppress tumor progression pathways, and stabilize neural circuitry through targeted ketone production.

Therapeutic ketogenic diets have been used for more than 100 years in the treatment of epilepsy and diabetes, and more recently as adjunct treatment in some types of cancer and in mental health.

These diets are very high in fat, from 65–72% (2:1) up to 90% (4:1). [1] Protein, fat, and carbohydrate are strictly controlled, so ingredients are weighed. Blood glucose and ketone levels are monitored to reach the desired Glucose to Ketone Index (GKI). [1]

What Are the Three Main Types of Therapeutic Ketogenic Diets?

Therapeutic ketogenic protocols are categorized by their specific macronutrient ratios of fat grams to combined protein and carbohydrate grams. These distinct configurations range from strict 4:1 and 3:1 medical interventions down to 2:1 protocols, with each variation calculated to meet specific clinical thresholds and therapeutic targets.

A therapeutic ketogenic diet is like a prescription, where each ingredient is weighed to achieve the specific ratio. High-fat, low-protein diets such as 4:1 and 3:1 ketogenic diets make Meal Plan design both time-consuming and challenging. People need to realize that “meals” in a therapeutic ketogenic diet are really an assembly of specific ingredients in precise amounts assembled to be as palatable as possible.

What Is a Classic 4:1 Ketogenic Diet?

The classic 4:1 ketogenic diet enforces a strict mathematical ratio of four grams of dietary fat for every single gram of combined protein and carbohydrate. This extreme macronutrient distribution delivers approximately 90% of total daily energy from fat sources and is primarily prescribed for severe pediatric epilepsy and drug-resistant seizure disorders.

The 4:1 KD is used for epilepsy and seizure disorders. The classic Ketogenic Diet (KD) has a 4:1 ratio, i.e., 4 parts of fat for every 1 part protein and carbohydrate. That is, for every 5 grams of food, there are 4 grams of fat and 1 gram of protein and/or carbohydrate. [1]

What Is a 3:1 Modified Ketogenic Diet?

A 3:1 modified ketogenic diet provides three grams of fat for every one gram of combined protein and carbohydrate, translating to roughly 75% of total calories derived from fat. Clinically, this ratio serves as a metabolic adjunct therapy alongside standard oncology treatments to exploit the metabolic vulnerabilities of advanced malignancies.

The Modified Ketogenic Diet (MKD) has a 3:1 ratio, i.e., 3 parts fat for every 1 part protein and carbohydrate, with 75% of calories from fat, and 25% from a combination of protein and carbohydrate. A 3:1 therapeutic ketogenic diet may be used along with chemotherapy or radiation for cancers like glioblastoma, or, as outlined in the update of this article, in hormone receptor-positive breast cancer. Protein may be set at 15% of calories, with a maximum of 10% of calories coming from carbohydrate.

What Is a 2:1 Modified Atkins Diet?

The 2:1 Modified Atkins Diet provides two grams of dietary fat for every one gram of protein and carbohydrate combined. This clinical framework structures daily energy intake around 60% fat, 30% protein, and 10% carbohydrates, offering a more manageable therapeutic option while maintaining necessary metabolic ketosis.

The Modified Atkins Diet (MAD) has a 2:1 ratio, with 2 parts fat for every 1 part protein and carbohydrate. Fat is set at 60% of calories, protein at 30% of calories, and carbohydrate at 10% of calories.

Is the “Keto” Diet a Type of Therapeutic Ketogenic Diet?

The popularized consumer keto diet targets general weight loss and glycemic optimization by restricting total carbohydrates to roughly 10% of daily energy. Unlike rigid medical prescriptions, consumer variations do not regulate absolute protein thresholds, require exact gram-weight measurements, or demand consistent laboratory monitoring of circulating ketones.

There is no one “keto diet”, but rather a range of keto diets. They all limit carbs to about 10% of daily calories to encourage ketone production. The popular high-fat / moderate protein version of a keto diet with ~75% fat and 15% protein is commonly referred to as “the keto diet,” but this is not the only keto diet, nor the first.

The high-fat, moderate-protein version became popular in 2016 with the publication of Dr. Jason Fung’s books, The Obesity Code [2] and The Complete Guide to Fasting [3]. Unlike therapeutic diets, protein is not tightly regulated in the popularized keto diet. Food does not need to be weighed, and ketones do not need to be monitored. These diets are often used for weight loss or blood sugar control, but are not therapeutic diets.

What is a Well-Formulated Keto Diet?

A well-formulated ketogenic diet for improving metabolic health maintains physiological ketosis while adjusting protein intake to 21% to 30% of total daily energy. In an aging demographic, prioritizing this higher protein range is vital to sustain skeletal muscle synthesis, preserve lean body mass, and mitigate the development of age-related sarcopenia.

In their book, The Art and Science of Low Carbohydrate Living [7], Dr. Stephen Phinney and Dr. Jeff Volek outline a “well-formulated ketogenic diet.” Since ketosis can occur within a fat intake range between 65-85% of calories, protein intake can range from 21-30%. Although this diet specifies the amount of protein, fat, and carbs for weight loss and maintenance, it is not classified as a therapeutic ketogenic diet.

It is my opinion that a well-formulated ketogenic diet containing 21–30% protein is preferable for older adults to the 15% protein provided by popularized keto diets, as the higher amount will help older adults retain muscle mass and avoid sarcopenia.

Can a Therapeutic Ketogenic Diet be Used for Cancer?

Recent peer-reviewed oncology case evidence demonstrates that a structured 3:1 therapeutic ketogenic diet can help manage specific, advanced, conventional treatment-resistant malignancies when combined with chemotherapy and radiation. This adjunct approach helps suppress circulating glucose levels, restricting the primary metabolic fuel source utilized by highly glycolytic tumor cells.

Emerging studies, such as the one that was published on April 21, 2026, in Frontiers in Oncology Cancer Metabolism [8], documented the successful use of a 3:1 therapeutic ketogenic diet as an adjunct treatment in hormone receptor-positive (HR+) breast cancer [8] and are encouraging. It provides documentation that a therapeutic ketogenic diet may be an effective adjunct treatment alongside chemotherapy for this largely incurable form of breast cancer once resistance to conventional treatments occurs [8].

What Are the Practical Constraints of a Therapeutic Ketogenic Diet?

Executing a true therapeutic ketogenic diet requires strict adherence to custom mathematical ratios and precise gram-scale food measurements. Because protein and carbohydrates are highly restricted, typical commercial keto meals are clinically unsuitable, making ongoing biochemical tracking of glucose and ketone levels mandatory for therapeutic success.

Both therapeutic ketogenic diets and keto diets limit carbohydrates, but therapeutic diets also tightly control protein. Therapeutic ketogenic diets also require precise weighing and tracking of glucose and ketones, as these diets are dietary prescriptions. Meals high in bacon, eggs, and meat, common in popularized keto diets, are not part of therapeutic ketogenic diets.

More Info

While popularized keto diets offer benefits such as weight loss and improved blood sugar, they are not therapeutic diets. I design both therapeutic ketogenic diets and different types of keto diets and support people in implementing and transitioning between them based on individual goals.

Learn about me and the types of therapeutic ketogenic diets I design as adjunct therapy for physical and mental health conditions, which are implemented under a doctor’s oversight. View my Therapeutic Diet Services page.

To your good health,

Joy

You can follow me on:

Twitter: https://twitter.com/jyerdile
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References

1. Kossoff, E. H., Turner, Z., Cervenka, M. C., & Barron, B. J. (2020). Ketogenic Diet Therapies for Epilepsy and Other Conditions: Seventh Edition. Springer Publishing Company. [https://www.springerpub.com/ketogenic-diet-therapies-for-epilepsy-and-other-conditions-9780826149589.html]
2. Fung, J. (2016). The Obesity Code: Unlocking the Secrets of Weight Loss. Greystone Books. [https://greystonebooks.com/products/the-obesity-code]
3. Fung, J., & Moore, J. (2016). The Complete Guide to Fasting: Heal Your Body Through Intermittent, Alternate-Day, and Extended Fasting. Victory Belt Publishing. [https://www.victorybelt.com/product/the-complete-guide-to-fasting/]
4. Eenfeldt, A. (2017). Low Carb, High Fat Food Revolution: Advice and Recipes to Improve Your Health and Reduce Your Weight. Skyhorse Publishing. [https://www.skyhorsepublishing.com/9781510710139/low-carb-high-fat-food-revolution/]
5. Eades, M. R., & Eades, M. D. (1997). Protein Power: The High-Protein/Low-Carbohydrate Way to Lose Weight, Feel Fit, and Boost Your Health—in Just Weeks! Bantam Books. [https://www.penguinrandomhouse.com/books/44226/protein-power-by-michael-r-eades-md-and-mary-dan-eades-md/]
6. Westman, E. C., Phinney, S. D., & Volek, J. S. (2010). The New Atkins for a New You: The Ultimate Diet for Shedding Weight and Feeling Great. Atria Books. [https://www.simonandschuster.com/books/The-New-Atkins-for-a-New-You/Eric-C-Westman/9781439190272]
7. Volek, J. S., & Phinney, S. D. (2011). The Art and Science of Low Carbohydrate Living: An Expert Guide to Making the Life-Saving Benefits of Carbohydrate Restriction Sustainable and Enjoyable. Beyond Obesity LLC. [https://www.artandscienceoflowcarb.com/the-art-and-science-of-low-carbohydrate-living/]
8. Slocum AK, Tastekin D, Duraj T and Seyfried TN (2026). Management of advanced HR-positive breast cancer using metabolically supported chemotherapy and repurposed drugs: a case report. Front. Oncol. 16:1795402. doi: 10.3389/fonc.2026.1795402

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Joy Erdile, MSc, RD

I am a Registered Dietitian Nutritionist and the owner of BetterByDesign Nutrition Ltd. With a postgraduate degree in Human Nutrition and a background as a published mental health nutrition researcher, I have been dedicated to supporting my clients’ clinical needs since 2008.

I hold active professional licenses in BC (CHPBC), Alberta (CDA), and Ontario (CDO), allowing me to provide regulated Medical Nutrition Therapy across these provinces. My expertise spans chronic disease management, complex digestive health, and therapeutic diets. I am deeply passionate about helping people reclaim their health, rooted in my firm belief that Nutrition is BetterByDesign©.