Today, I review, link to, and excerpt from The ketogenic diet is not for everyone: contraindications, side effects, and drug interactions [PubMed Abstract] [Full-Text HTML] [Full-Text PDF]. Ann Med. 2026 Dec;58(1):2603016. doi: 10.1080/07853890.2025.2603016. Epub 2026 Jan 4.
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All that follows is from the above article.
- Abstract
- Graphical abstract
- 1. Introduction
- 2. Methodology
- 3. The ketogenic diet and the state of ketosis
- 4. Absolute contraindications to the ketogenic diet (all very rare but important)
- 5. Relative contraindications to the ketogenic diet
- 6. Situations in which special care should be taken when following the ketogenic diet
- 7. KD and drug interactions
- 8. Possible side effects of KD
- 9. Potential problems with the KD in clinical practice
- 10. Strengths and limitations
- 11. Conclusions
- Acknowledgments
- Funding Statement
- Disclosure statement
- Data availability statement
- References
- Associated Data
Abstract
Background: The ketogenic diet (KD), initially developed for the treatment of neurological disorders, has gained increasing attention for its potential role in the management of various metabolic diseases. Alongside its expanding clinical use, concerns have emerged regarding its safety, tolerability, and suitability in specific patient populations. This review summarises key contraindications, clinical situations requiring caution, relevant drug interactions, and commonly reported adverse effects associated with KD.
Discussion: Rare absolute contraindications include selected inborn errors of metabolism affecting pyruvate carboxylase activity, carnitine transport or utilisation, fatty acid oxidation pathways, as well as porphyria. Relative contraindications encompass acute pancreatitis, advanced hepatic or renal disease, familial hypercholesterolaemia, and other conditions that may be aggravated by KD-induced metabolic changes, including concomitant use of propofol. Particular caution is warranted in patients with type 1 or type 2 diabetes receiving specific glucose-lowering therapies, pharmacologically treated hypertension, gallbladder disease or prior cholecystectomy, electrolyte disturbances, cardiac arrhythmias, pregnancy or lactation, underweight status, intense physical activity, significant psychosocial stress, or postoperative recovery.Clinically relevant interactions with medications are reviewed, including sodium-glucose cotransporter 2 (SGLT2) inhibitors, metformin, glucagon-like peptide-1 (GLP-1) receptor agonists, insulin and sulphonylurea derivatives, antiepileptic drugs, diuretics, lipophilic drugs, and corticosteroids. The most frequently reported adverse effects range from transient “keto flu” symptoms (fatigue, headache, nausea) to gastrointestinal disturbances, polyuria, and hypoglycaemia.
Conclusions: KD demonstrates therapeutic potential in the management of a broad range of metabolic and neurological diseases; however, it is not an intervention suitable for all clinical situations. Awareness of existing contraindications, conditions requiring particular caution, and potential drug interactions enables a more responsible, individualised, and safe approach to patient selection and clinical management. In this context, the present paper provides a concise yet comprehensive synthesis to support clinicians and researchers in the rational and effective application of the ketogenic diet in both clinical practice and scientific research.
Keywords: Ketogenic diet (KD); absolute contraindications; diseases; drug interactions; relative contraindications; side effects.
Keywords: Ketogenic diet (KD), absolute contraindications, relative contraindications, drug interactions, side effects, diseases
Graphical abstract
1. Introduction
The ketogenic diet (KD) has been in clinical use for over a century since 1921, when it was first used in the treatment of epilepsy [1,2]. However, recent years have seen a rapidly growing interest in this dietary model. A manifestation of this trend is the sharp increase in the number of scientific publications on KD, reflecting the intense search for new potential clinical applications. The beneficial antiepileptic effects of KD raise legitimate questions about the effect of this diet in other brain disorders and diseases, such as Alzheimer’s disease (AD) [3], Parkinson’s disease (PD) [4], multiple sclerosis (MS) [5], migraine [6], and brain tumour [7,8]. There is also a growing number of promising findings on the action of KD in mental illnesses including schizophrenia and bipolar affective disorder [9,10], depression [11], and others [12–16]. For many years, research has also been moving beyond neurology, demonstrating the benefits of KD in other conditions such as type 2 diabetes, where it can often lead to a reduction or complete discontinuation of medication, accompanied by a remission [17–20]. Other areas of research include obesity [21–23], metabolic dysfunction-associated fatty liver disease (MAFLD) [24], cardiovascular diseases [25,26], cancer [27,28], and polycystic ovary syndrome (PCOS) [29,30]. Findings in inflammatory bowel disease (IBD) are also promising, albeit still preliminary [31]. The ketogenic diet is also gaining popularity in the context of sports and physical activity. Although its effectiveness compared to traditional dietary models remains a subject of debate, an increasing number of studies are investigating its impact on physical performance, metabolic adaptation, and recovery [32–34].
The multifaceted (and often successful) clinical application of the ketogenic diet and the growing popularity of this nutritional model calls for a discussion of potential contraindications, side effects and situations in which this particular diet should be used with particular care. Like all other dietary models, the ketogenic diet is not right for everyone. By discussing these concerns, specialists can develop a more responsible and reliable approach to the ketogenic diet.
2. Methodology
This manuscript is a narrative review, intentionally chosen due to the heterogeneity of the included evidence (clinical guidelines, mechanistic studies, narrative reviews, case reports, observational studies and expert recommendations), which cannot be synthesised using systematic methods. Searches were primarily conducted in PubMed and Google Scholar. The initial search strategy employed broad combinations of keywords related to the ketogenic diet (e.g. ‘ketogenic diet’, ‘ketosis’), safety considerations (‘absolute contraindications’, ‘relative contraindications ‘, ‘drug interactions’, ‘side effects’, ‘adverse effects’), and clinical conditions potentially affecting ketogenic therapy. To develop a comprehensive review, when individual articles identified a specific contraindication, comorbidity, or safety concern (e.g. acute pancreatitis, primary carnitine deficiency, gallbladder disease, use of SGLT-2 inhibitors), additional targeted searches were performed using the name of the condition or drug together with terms such as ‘ketogenic diet’ or ‘ketosis’. This approach allowed the inclusion of evidence that might not have been captured through broader search strategies.
Selection was based on article titles, abstracts, and full texts.
