Quick answer: On keto, lower insulin makes the kidneys release more sodium and water, and potassium and magnesium can fall too. Low electrolytes may contribute to keto flu symptoms like fatigue, headaches, dizziness and cramps. Eating electrolyte-rich foods, using broth or an electrolyte drink, and staying hydrated help. People with kidney disease, heart disease or high blood pressure should get personal advice.
Key takeaways
Electrolytes such as sodium, potassium and magnesium control fluid balance, nerve signals, muscle contraction and heart rhythm.
As insulin falls on keto, the kidneys release more sodium and water, which can pull potassium and magnesium along and add to keto flu.
Broth, olives, avocado, leafy greens, nuts and seeds supply electrolytes, and an electrolyte drink without added sugar is another option.
Why electrolytes matter
Electrolytes are minerals that control fluid balance, nerve signals, muscle contraction and heart rhythm.
Electrolytes on keto
As glycogen is used and insulin falls, the kidneys excrete more sodium and water, pulling potassium and magnesium with them. This may contribute to keto flu symptoms.
Food sources
- Sodium: sea salt, broth, pickles, olives, cheese
- Potassium: avocado, spinach, kale, almonds, salmon
- Magnesium: spinach, almonds, pumpkin seeds, chard, dark chocolate
Electrolyte drinks
I often suggest an electrolyte powder without added sugar or a little coconut water as an easy option. Check labels for sugar.
How much?
NIH provides general daily intake recommendations for adults, and needs on keto can differ. Extra sodium or potassium can be harmful with kidney disease, heart failure, high blood pressure or certain medications.
Healthy aging lens
Electrolyte balance supports heart rhythm and muscle function at every age. See hydration and electrolytes.
When to see a naturopathic doctor
It may be time to see a naturopathic doctor if you have diabetes or take insulin, sulfonylureas or SGLT2 inhibitors (risk of low blood sugar or ketoacidosis), or if you take blood pressure medication or diuretics. The same is true if you have kidney, liver, gallbladder or pancreas disease, or high cholesterol, if you are pregnant, breastfeeding, or have a history of disordered eating, or if you want a keto plan tailored to your labs and goals.
See a medical provider promptly for nausea and vomiting, abdominal pain, confusion, fruity-smelling breath with rapid breathing, or very high blood sugar or ketone readings, which can signal ketoacidosis.
What the research shows
Research on electrolytes during keto is limited. The best description of “keto flu” comes from a 2020 study by Bostock and colleagues, which analyzed 448 posts from 300 people on 43 online forums. About a third (101 people) described symptoms, most often flu-like feelings, headache, fatigue, nausea, dizziness and brain fog, usually in the first week or two. Many forum users mentioned electrolytes as a remedy. Because these were self-reports from the internet, the study cannot tell us how common keto flu is or whether electrolytes are what helped.
Potassium has stronger human evidence. A 2013 BMJ review by Aburto and colleagues combined 22 randomized trials with 1,606 participants and found that higher potassium intake lowered systolic blood pressure by about 3.5 mm Hg, with the effect seen in people with high blood pressure but not in those without it. In 11 cohort studies with 127,038 people, higher potassium intake was linked to a 24% lower risk of stroke. Kidney function and blood lipids were not affected in adults. These trials were not done in people on keto, and people with kidney disease or on certain blood pressure medicines need guidance before adding potassium.
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Questions to bring to your clinician
These questions can help you get the most out of your next visit.
Is it safe for me to add extra salt or electrolytes, given my blood pressure and kidney health?
How much sodium, potassium and magnesium would I need on keto?
Could my blood pressure or kidney health change how I handle electrolytes?
Which signs would tell me my electrolytes are out of balance?
Frequently asked questions
Why do I need more electrolytes on keto?
Lower insulin makes your kidneys excrete more sodium and water.
What are signs of low electrolytes?
Fatigue, headaches, dizziness and muscle cramps.
What foods are high in electrolytes?
Broth, avocado, leafy greens, nuts and seeds.
Who should be careful with electrolyte supplements?
People with kidney or heart disease, high blood pressure, or on related medications.
Sources
- Bostock ECS, Kirkby KC, Taylor BV, et al. Consumer Reports of "Keto Flu" Associated With the Ketogenic Diet. Front Nutr 2020. PMID: 32232045. https://pubmed.ncbi.nlm.nih.gov/32232045/
- Aburto NJ, Hanson S, Gutierrez H, et al. Effect of increased potassium intake on cardiovascular risk factors and disease: systematic review and meta-analyses. BMJ 2013. PMID: 23558164. https://pubmed.ncbi.nlm.nih.gov/23558164/
- de Baaij JH, Hoenderop JG, Bindels RJ. Magnesium in man: implications for health and disease. Physiol Rev 2015. PMID: 25540137. https://pubmed.ncbi.nlm.nih.gov/25540137/
- Brands MW, Manhiani MM. Sodium-retaining effect of insulin in diabetes. Am J Physiol Regul Integr Comp Physiol 2012. PMID: 23034715. https://pmc.ncbi.nlm.nih.gov/articles/PMC3533616/
- Kovesdy CP. Management of hyperkalaemia in chronic kidney disease. Nat Rev Nephrol 2014. PMID: 25223988. https://pubmed.ncbi.nlm.nih.gov/25223988/
- NIH ODS: Magnesium
- MedlinePlus: Potassium
This article is for educational purposes only and is not medical advice. It does not replace an individual evaluation. Talk with your healthcare provider before starting supplements or changing medications, especially if you are pregnant, nursing, or managing a health condition.
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