Low-Carb Quick Weight Loss Doesn’t Hold Water or Electrolytes

Alright, so you can lose weight fast with a low-carb diet. The lack of carbs will send the liver and muscles for their glycogen storage using up water and stimulating increased production of urine, or polyuria (1). Along with the osmotic diuresis, or increased urination, will be loss of sodium and potassium (1-2).

Couple that with a change of diet that eliminates water-retaining carbohydrates and foods high in potassium and water (such as fruits), and the diet could lead to dehydration and othostatic hypotension as well as potassium deficiency (1-2). Fatigue sets in due to used up glycogen stores (1). Exacerbating these potentials are appetite suppression and possible vomiting resulting from nausea, common in low-carb diets, which can lead to more depletion of electrolytes (1).

Even a moderate deficiency of potassium can increase calcium excretion, elevate blood pressure and cause abnormal bone turnover (2p455). If hypokalemia occurs from heavy loss of potassium (such as from vomiting), then there would be an increased risk of cardiac arrhythmia, muscle weakness, irritability, hypercalciuria, glucose intolerance and mental disorientation (2p455).

Potassium supplements can correct potassium deficiency, but too much can be toxic, producing hyperkalemia, which can lead to severe cardiac arrhythmias and cardiac arrest (2p455).


1. Hirschel B. [Dr. Atkins’ dietetic revolution: a critique]. Schweiz Med Wochenschr 1977;107:1017-25.

2. Gropper SS, Smith JL, Groff JL. Advanced Nutrition and Human Metabolism. Belmont, CA: Thomson Wadsworth, 2009.

Published by David Despain, MS, CFS

David is a science and health writer living on Long Island, New York. He's written for a variety of publications including Scientific American, Outside Online, the American Society for Nutrition's (ASN) Nutrition Notes Daily, and Institute of Food Technologists' (IFT) Food Technology magazine and Live! blog. He's also covered new findings reported at scientific meetings including Experimental Biology, AAAS, AOCS, CASW, Sigma Xi, IFT, and others on his personal blog "Evolving Health." David is also an active member of organizations including the National Association of Science Writers (NASW), the American Association for the Advancement of Science (AAAS), the American Society for Nutrition, the Institute of Food Technologists, and the National Audubon Society. David has a master's degree in human nutrition from the University of Bridgeport, and a bachelor's degree in English from University of Illinois at Springfield. He also earned his Certified Food Scientist credential from the Institute of Food Technologists.

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