The ketogenic diet is a metabolic approach that involves severely restricting carbohydrate intake, typically to under 50 grams per day, and replacing it with fat to encourage the body to burn fat for fuel. This shift in macronutrients initiates a state called ketosis, which alters how the body manages fluids and minerals. For the average person, health recommendations often focus on restricting sodium intake, but this dynamic changes completely when following a very low-carbohydrate plan. Unlike a standard diet, salt is not merely permitted on a ketogenic diet, it becomes a biological necessity to maintain proper bodily function. Ignoring the need for increased sodium can lead to uncomfortable side effects that often derail initial efforts.
Why Sodium Needs Increase on a Ketogenic Diet
The primary reason sodium requirements increase on a ketogenic diet stems from a significant change in hormone levels, specifically insulin. When carbohydrate intake is drastically reduced, the body produces far less insulin, which is a desirable metabolic outcome. However, insulin plays a lesser-known role in signaling the kidneys to retain sodium and water.
A drop in circulating insulin levels signals the kidneys to excrete higher amounts of water and electrolytes, including sodium, a process known as natriuresis. This loss of fluid is why many people experience rapid “water weight” loss during the first few days of a ketogenic diet. This physiological dumping of sodium and fluid is compounded by the depletion of glycogen stores.
Glycogen, the storage form of carbohydrates in the liver and muscles, is bound to a large amount of water—approximately three to four grams of water for every one gram of glycogen. As the body rapidly uses up these glycogen reserves, the associated water and electrolytes, including sodium, are flushed out. This rapid, simultaneous loss of both fluid and sodium quickly compromises the body’s sodium balance, making active replenishment necessary.
Identifying Symptoms of Low Sodium
The body’s sudden loss of fluid and sodium often manifests as the “keto flu,” which are unpleasant, temporary side effects largely resulting from electrolyte imbalance. A common symptom is a persistent, dull headache that does not respond well to typical pain relievers.
Fatigue and general weakness are also frequently reported, as sodium is necessary for maintaining proper fluid balance and nerve function. Another tell-tale sign is orthostatic hypotension, or dizziness and lightheadedness that occur when standing up quickly. This is due to a reduction in overall blood volume caused by the fluid loss.
Muscle cramps, particularly in the legs, often strike at night and signal broader electrolyte depletion. Experiencing these symptoms suggests an immediate need for sodium replenishment. Consuming salted broth or bouillon can often provide rapid relief by quickly restoring lost sodium and fluid volume.
Actionable Strategies for Meeting Sodium Targets
Because of the physiological changes induced by carbohydrate restriction, the sodium intake recommendations for a ketogenic diet are significantly higher than the standard dietary guidelines. While most guidelines recommend limiting sodium to under 2,300 milligrams (mg) per day, individuals on a ketogenic diet generally need to consume between 3,000 and 5,000 mg of sodium daily. This higher range is necessary to offset the increased excretion rate and maintain fluid balance.
The most straightforward way to meet this target is by liberally salting food beyond what one might normally consider sufficient. Salt all meals to taste, as you may find yourself adding more than you did on a higher-carbohydrate diet. Regular consumption of bone broth or bouillon cubes dissolved in hot water is another highly effective method. A single serving of bouillon can deliver several hundred milligrams of sodium and is an easy way to supplement intake.
Electrolyte drink mixes or powders specifically designed for low-carb diets are also a convenient and precise way to ensure adequate daily intake. Common table salt (sodium chloride) is perfectly functional for meeting the sodium requirement. While some prefer mineral-rich alternatives like Himalayan pink salt or Celtic sea salt, the primary benefit remains the sodium content itself.