Electrolyte Calculator for Fasting and GLP-1 Days
Low-appetite days are low-electrolyte days. Add what you actually ate and drank, plus any electrolyte drink or supplement, and see sodium, potassium and magnesium against the official daily intakes.
| Food | Servings | Amount |
|---|
Sodium
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Potassium
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Magnesium
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Common questions
Why track electrolytes on a GLP-1 medicine?
Appetite drops, so food — where most potassium and magnesium come from — drops too. And the semaglutide label (Wegovy, section 5.5) reports acute kidney injury, mostly in people who had nausea, vomiting or diarrhea leading to volume depletion. If you are vomiting or have diarrhea and can't keep fluids down, call your prescriber.
What are the daily targets?
Sodium: under 2,300 mg (the National Academies' chronic disease risk reduction intake). Potassium: 2,600 mg for women, 3,400 mg for men (adequate intake). Magnesium: 310–320 mg for women and 400–420 mg for men, by age.
Can I take too much magnesium?
From supplements, yes: the upper limit for supplemental magnesium is 350 mg a day for adults. Food magnesium doesn't count toward it. High doses commonly cause diarrhea.
I'm fasting — how much salt should I add?
This page won't give a number: the official intakes are for everyday eating, not fasting protocols, and the right amount depends on your health and medicines. It shows how far your actual intake is from the everyday targets.
Method & sources
Food amounts = USDA FoodData Central per-100 g values × serving grams × servings; label amounts you type are added on top. Targets: sodium under 2,300 mg/day; potassium 2,600 mg (women) / 3,400 mg (men); magnesium RDA 310 mg (women 19–30), 320 mg (women 31+), 400 mg (men 19–30), 420 mg (men 31+). The supplement box is checked against the 350 mg supplemental-magnesium upper limit. Kidney disease and medicines such as ACE inhibitors, ARBs or potassium-sparing diuretics change the potassium picture — that's a clinician's call. Same food data and sodium/potassium targets as the sodium & potassium checker.
Sources
- NIH Office of Dietary Supplements. Magnesium — Health Professional Fact Sheet (RDAs; supplemental UL 350 mg). ods.od.nih.gov
- NIH Office of Dietary Supplements. Potassium — Health Professional Fact Sheet. ods.od.nih.gov
- National Academies. Dietary Reference Intakes for Sodium and Potassium (2019). nap.nationalacademies.org
- FDA. WEGOVY (semaglutide) prescribing information, section 5.5 Acute Kidney Injury. www.accessdata.fda.gov
- USDA FoodData Central. fdc.nal.usda.gov
On a GLP-1: water · fiber · calories · constipation foods · potassium-rich foods · magnesium-rich foods