There are several groups who are advised not to go on keto diets. Some of these recommendations are related to pre-existing medical conditions; others stem from a lack of data about whether keto is safe during certain development stages. These groups should not attempt this diet regimen (2, 6, 7):
Pregnant or breastfeeding women
People with disorders which affect fat oxidation on a mitochondrial level
People with unmanaged type 1 or type 2 diabetes
People with conditions affecting fatty acid synthesis
People with porphyria
People with enzyme deficiencies involved in various metabolic reactions (pyruvate carboxylase deficiency, acyl-CoA dehydrogenase deficiency)
People with primary carnitine deficiency
People with liver disease, kidney disease, or severe heart disease