Medical Conditions That Rule Out the Keto Diet
For a significant number of people, underlying health issues make the high-fat, low-carbohydrate nature of the keto diet medically inappropriate and potentially harmful. In these cases, the risk-benefit ratio is severely skewed toward potential harm.
Liver and Gallbladder Disease
The liver is responsible for producing bile and converting fats into ketone bodies during ketosis. Conditions that impair liver function, such as advanced liver disease or cirrhosis, can hinder this process and may be exacerbated by the strain of processing a high volume of fat. Furthermore, since the gallbladder stores and concentrates bile needed for fat digestion, individuals with gallbladder disease or who have had their gallbladder removed (cholecystectomy) may struggle with the high-fat intake required by the keto diet. A sudden increase in fat can trigger gallbladder issues and cause discomfort or complications.
Pancreatic Issues
The pancreas produces enzymes to aid in digestion and hormones like insulin to regulate blood sugar. A high-fat diet can overtax an already compromised pancreas. People with pancreatic disease, especially pancreatitis, are poor candidates for keto. In some cases, the drastic increase in fat can lead to elevated triglyceride levels, a known risk factor for acute pancreatitis. A dysfunctional pancreas cannot tolerate the metabolic shift the keto diet demands.
Kidney Problems and Kidney Stones
The kidneys play a vital role in filtering waste and maintaining electrolyte balance, which is significantly altered on a ketogenic diet. Concerns for individuals with chronic kidney disease (CKD) include an increased acid load on the kidneys, potentially worsening metabolic acidosis, and an elevated risk of developing kidney stones. Kidney stones are a well-documented risk associated with long-term keto diets, partly due to changes in urine pH and mineral excretion. While research is ongoing, caution is warranted for anyone with compromised kidney function.
Groups and Circumstances Warranting Caution or Avoidance
Beyond specific organ diseases, certain demographics and individual health histories should proceed with extreme caution or avoid the diet entirely.
Inborn Errors of Metabolism
For some individuals, a genetic predisposition affects how their body metabolizes fat. This makes the keto diet an absolute contraindication. These include rare inborn errors of metabolism, such as deficiencies in enzymes required for ketogenesis or ketolysis. For example, deficiencies in mitochondrial 3-hydroxy-3-methylglutaryl-CoA (HMG-CoA) synthase or lyase are particularly dangerous on a keto diet. For these individuals, a keto diet could trigger a metabolic crisis with severe and potentially fatal consequences.
Pregnancy, Breastfeeding, and Children
Pregnant women are strongly advised against the keto diet. The nutritional demands of a developing fetus are complex, and a restrictive, high-fat diet may lack critical nutrients, like folate, that are essential for proper fetal development. Some studies suggest low-carbohydrate diets are linked to an increased risk of neural tube defects. Similarly, safety data for breastfeeding women is lacking, and healthcare professionals generally advise against it. The classic ketogenic diet is used medically for children with refractory epilepsy, but it is a highly specialized and medically supervised treatment, not a general lifestyle choice for minors. Children and teenagers require a balanced diet for growth and development.
Type 1 and Type 2 Diabetes
While some studies investigate the keto diet for type 2 diabetes under strict medical supervision, it is not a universally recommended approach. For those with type 1 diabetes, the risk of diabetic ketoacidosis (DKA)—a life-threatening condition—is a major concern. The combination of a keto diet with SGLT-2 inhibitor medications, common for type 2 diabetes management, is especially dangerous, increasing the risk of euglycemic DKA (DKA with normal or near-normal blood glucose levels). Any diabetic considering keto must consult with their doctor to manage risks and adjust medication.
Eating Disorders and Disordered Eating
For individuals with a history of or a predisposition to eating disorders, the restrictive nature and rigid rules of the keto diet can trigger or worsen unhealthy behaviors. The obsession with specific macronutrient ratios and the elimination of entire food groups mirrors disordered eating patterns. A focus on weight loss and food restriction can intensify fixations on body image and food, leading to psychological distress and relapse.
| Feature | Good Candidate for Keto | Not a Good Candidate for Keto |
|---|---|---|
| Health Status | Generally healthy, metabolically stable | Liver, kidney, pancreatic disease |
| Energy Source | Body efficiently uses fat and ketones | Impaired fat metabolism (genetic) |
| Life Stage | Non-pregnant, non-breastfeeding adult | Pregnant or breastfeeding women |
| Diabetes | Potentially for Type 2, with strict medical supervision | Type 1 Diabetes (high risk of DKA) |
| Medication Use | Not on SGLT-2 inhibitors | Taking SGLT-2 inhibitors (risk of euDKA) |
| Mental Health | Healthy relationship with food | History of eating disorders |
Lifestyle and Other Nutritional Considerations
Even without a specific medical contraindication, the practicality and nutritional completeness of a keto diet can be challenging for many.
Nutrient Deficiencies and Fiber Intake
The severe restriction of carbohydrates often means eliminating or severely limiting many fruits, whole grains, and starchy vegetables. These are primary sources of fiber, vitamins, and minerals. Over time, this can lead to nutrient deficiencies and common gastrointestinal issues like constipation. A lack of fiber can also disrupt the gut microbiome, impacting overall health. Ensuring proper micronutrient intake requires careful planning and often, supplementation, which adds complexity.
Sustainability and Social Factors
The restrictive nature of the keto diet makes it difficult to maintain long-term for many people. This can lead to a cycle of yo-yo dieting, where weight is lost and then regained when the diet is abandoned. The social implications can also be significant. Navigating restaurants, social gatherings, and family dinners can be challenging, and some people experience social isolation as a result of their dietary limitations. For those who struggle to stick to a restrictive regimen, a more balanced and sustainable dietary approach is often a better long-term strategy.
Conclusion: Always Consult a Professional
While the ketogenic diet can be an effective medical tool for specific conditions like epilepsy under careful supervision, it is not a suitable or safe choice for everyone. The list of individuals who are not good candidates for keto is extensive, ranging from those with existing liver or kidney disease to pregnant women and people with a history of eating disorders. Before making any drastic changes to your diet, it is essential to consult with a qualified healthcare professional, such as a doctor or registered dietitian. They can assess your individual health status and determine if a ketogenic diet is appropriate or if a more balanced and sustainable nutrition plan would better serve your health goals.
