Heart Palpitations on Keto: Usually This One Mineral

Heart palpitations can be unsettling when starting a ketogenic diet. The culprit is often an electrolyte imbalance, specifically magnesium deficiency. Ketogenic diets alter how the body retains minerals, and heart palpitations frequently signal this adjustment period.

Why electrolytes matter on keto

When carbohydrate intake drops below 50g daily, insulin levels decrease. This causes the kidneys to excrete more sodium, taking potassium and magnesium with it. A 2013 study in the British Journal of Nutrition found very-low-carb diets increase urinary magnesium loss by 25-30% compared to low-fat diets (Bueno et al., 2013).

The magnesium connection

Magnesium regulates heart rhythm through its role in muscle and nerve function. The NHS recommends 300mg daily for men and 270mg for women. On keto, requirements may increase to 400-500mg. Symptoms of deficiency include palpitations, muscle cramps, and fatigue.

What this means in practice

Boost magnesium intake through food first:

Spinach (80mg per 100g at Tesco, £1.20 for 200g)
Almonds (80mg per 30g handful)
Dark chocolate (50mg per square of 85% cocoa)

During warmer months or after exercise, consider supplementing with magnesium citrate or glycinate. Avoid magnesium oxide, which has poor absorption.

Rebalancing other electrolytes

While magnesium is often the main issue, sodium and potassium also play roles. Add a pinch of salt to water and eat potassium-rich foods like avocado and mushrooms. keto electrolyte supplements can help during adaptation.

Frequently asked questions

Are heart palpitations dangerous on keto?

Occasional palpitations during keto adaptation are usually harmless if you’re otherwise healthy. Persistent or severe symptoms warrant medical review, especially with dizziness or chest pain.

How long do keto heart palpitations last?

Most people adjust within 2-4 weeks with proper electrolyte management. Those taking diuretics or with pre-existing conditions may need longer.

Can I drink sports drinks for electrolytes?

Standard sports drinks contain too much sugar and too little magnesium. Opt for sugar-free electrolyte tablets or homemade solutions with salt and lo-salt instead.

The bottom line

Heart palpitations on keto typically stem from magnesium deficiency exacerbated by increased urinary losses. Prioritise magnesium-rich foods and consider supplementation during adaptation. Monitor symptoms and consult your GP if concerns persist. If you’d rather not do the macro maths yourself, the Keto Dieting app does it for you on Google Play and the App Store.

Educational only — not medical advice. This article is for general information. Speak to your GP before changing your diet, especially if you have type 1 or type 2 diabetes, kidney or liver disease, are pregnant or breastfeeding, or take medication for blood pressure, cholesterol, or blood glucose.

References

Bueno NB, de Melo IS, de Oliveira SL, da Rocha Ataide T (2013). Very-low-carbohydrate ketogenic diet v. low-fat diet for long-term weight loss: a meta-analysis of randomised controlled trials. British Journal of Nutrition. https://doi.org/10.1017/S0007114513000548
Hyde PN, Sapper TN, Crabtree CD, et al. (2019). Dietary carbohydrate restriction improves metabolic syndrome independent of weight loss. JCI Insight. https://doi.org/10.1172/jci.insight.128308