The Complete Keto Electrolyte Guide: Sodium, Potassium & Magnesium Targets

1. Renal Physiology: Natriuresis of Fasting & Aldosterone Downregulation

In the presence of elevated circulating insulin, the kidneys actively reabsorb sodium in the distal and proximal renal tubules. When you restrict dietary carbohydrates below 20g, basal insulin plunges within 48 hours.

This triggers natriuresis of fasting: the kidneys rapidly dump sodium into urine. Water follows sodium by osmotic pressure, dragging potassium with it. Without conscious sodium replenishment, plasma volume contracts, leading to hypotension, elevated heart rate, and severe fatigue.

Compensatory aldosterone release attempts to conserve sodium by actively excreting potassium in the distal nephron, compounding intracellular mineral depletion.

2. Quantitative Daily Baselines: Sodium, Potassium & Magnesium

Standard dietary guidelines recommending under 2,300mg of sodium assume a high-carbohydrate, insulinogenic diet. In nutritional ketosis, clinical consensus from researchers like Dr. Stephen Phinney establishes the following daily baseline:

• Sodium: 5,000mg elemental sodium (~12.5g of unrefined sea salt or kosher salt) spread across the day. • Potassium: 1,000mg to 3,500mg elemental potassium derived primarily from whole foods (spinach, avocado, salmon, mushrooms). • Magnesium: 300mg to 400mg bioavailable elemental magnesium (such as magnesium glycinate or malate; avoid magnesium oxide, which has a 4% absorption rate and acts primarily as an osmotic laxative).

3. Differential Symptom Diagnosis: Pinpointing Your Deficiency

When dieters feel unwell, they often guess at remedies. Differential diagnosis reveals exactly which mineral is depleted:

• Sodium Deficiency: Postural lightheadedness upon standing, throbbing frontal tension headache, exercise fatigue, brain fog, and salt cravings. • Potassium Deficiency: Muscle heaviness, resting tachycardia (racing heart rate), and sensation of skipped heartbeats. • Magnesium Deficiency: Nocturnal calf and foot cramps, involuntary eyelid twitches, neuromuscular hyperexcitability, and restless sleep.

Taking potassium when you are sodium-depleted worsens hypotension; diagnosing the specific deficient cation is critical for rapid symptom resolution.

4. Whole-Food Mineral Delivery vs. Supplementation

Relying solely on salty snacks or synthetic drink mixes can irritate the gastric mucosa. Repast solves mineral requirements directly through recipe design: simmering bone broths with coarse sea salt, finishing pan-seared proteins with flaky finishing salt, and incorporating potassium-rich dark leafy brassicas into daily dinners.

A medium Hass avocado delivers 700mg of organic potassium, 40mg of magnesium, and 10g of fiber. A 200g portion of wild salmon provides 900mg of potassium. Real whole foods provide organic mineral complexes with superior cellular uptake.

5. Chrono-Dosing: Morning Salt Water to Evening Glycinate

Mineral timing optimizes physiological absorption and avoids gastrointestinal distress:

• 07:00 AM: 500ml water with 1.5g dissolved sea salt (approx. 600mg sodium) to restore morning plasma volume and blunt cortisol. • 12:30 PM & 06:30 PM: Liberal salting of primary meals with high-potassium vegetable sides. • 09:30 PM: 350mg magnesium glycinate taken 45 minutes before sleep to facilitate GABAergic neural relaxation and prevent nighttime calf cramps.

This synchronized chrono-dosing schedule eliminates the digestive urgency that occurs when high doses of mineral salts are consumed in a single sitting.