After 10 years coaching low carb clients in Metro Manila, including overweight clients, women with PCOS, hypertensive clients, and type 2 diabetics, I’ve found potassium is the most overlooked mineral of all. Most people blame the diet itself when cramps or dizziness show up in week one. But almost always, it’s electrolytes, and potassium specifically is usually the missing piece.
Potassium is an electrolyte stored mostly inside your cells, about 98% of it, especially in muscle tissue. It works alongside sodium, magnesium, and chloride to regulate fluid balance, muscle contractions, heart rhythm, nerve signaling, and blood pressure. It’s not just “the cramp mineral.” It’s required for basic survival functions.
Because of a direct chain reaction, not a coincidence. When you reduce carbohydrates, insulin drops. Lower insulin then signals your kidneys to release more sodium. Water follows the sodium out, and potassium follows right along with the water. So week one of low carb usually means more urination and quick water-weight loss. For a lot of people, it also means weakness, dizziness, or cramps. Most people call this “keto flu.” Really, though, it’s an electrolyte shift, and it’s fixable within days once you know what’s actually happening.
| System affected | What you might notice |
|---|---|
| Muscles | Night leg cramps, tight calves, foot spasms |
| Heart | Palpitations, a fluttering sensation, anxiety-like symptoms |
| Nerves and energy | Dizziness, weakness, fatigue |
| Digestion | Constipation |
These symptoms cluster heavily in the first week of carb restriction. In my experience, though, they’re preventable almost entirely with the right food and electrolyte strategy from day one.
Yes, and the evidence is solid. A systematic review and meta-analysis published in The BMJ found that higher potassium intake meaningfully lowers blood pressure in people with hypertension. It also reduces stroke risk, with no adverse effect on kidney function or cholesterol in the general population studied. Potassium works by helping your body excrete sodium while supporting healthy blood vessel function.
In my hypertensive clients, blood pressure often improves further once potassium intake is corrected, on top of the improvement low carb already provides. That said, if you’re on blood pressure medication, keep taking it. Loop in your physician before making changes too. See can a low carb diet lower blood pressure for the full picture on diet and BP.
A recurring pattern in my PCOS clients specifically: fatigue, dizziness, cycle disruption, and cravings returning during the carb transition. Many assume it’s purely hormonal. Often, electrolyte imbalance, potassium in particular, is contributing more than people realize. Correcting it tends to improve energy and cravings noticeably, sometimes within the first couple of days.
In hypertensive clients starting low carb, I commonly see blood pressure fluctuate and mild palpitations show up in week one. Instead of assuming the diet is failing, I review sodium, potassium, and hydration together. That usually resolves it, while the client stays on their prescribed medication and under physician guidance the whole time.
| Food | Why it works |
|---|---|
| Coconut water | One of the best natural sources; keep to about 1 to 2 servings a day |
| Avocado | Low carb, high potassium, high fiber |
| Malunggay (moringa) | Affordable, accessible, nutrient-dense |
| Pechay / bok choy | Easy to add to soups and stir-fries |
| Salmon | Protein plus potassium in one food |
| Pork | An often-overlooked potassium source |
For the full list of Filipino low carb staples, not just potassium sources, see my list of low carb foods for Filipinos.
They are, but they’re also high in carbs. On strict low carb, I steer clients toward avocado or coconut water instead. If you’re doing a more moderate carb approach rather than strict keto, though, a small banana portion earlier in the day can still fit. Just don’t treat it as your main potassium strategy.
In both directions, which is why this needs real attention, not guesswork. Too little potassium (hypokalemia) is common in early carb restriction. I see it more often in women with PCOS or other hormonal imbalances. Too much potassium (hyperkalemia) is a different risk entirely. It’s more relevant for people on ACE inhibitors or ARBs for blood pressure, and especially for those with existing kidney disease. Don’t mega-dose potassium supplements on your own, and if you’re in a higher-risk group, get labs monitored rather than guessing.
For higher-risk individuals, I recommend tracking serum potassium, sodium, creatinine, eGFR, and magnesium periodically. This matters especially if you’re diabetic, hypertensive, or have any kidney involvement.
Because rice barely touches the actual problem. Rice is a starch, not a meaningful potassium source, so adding it back raises insulin again without fixing the mineral deficit that caused the symptoms. That’s the trap I see constantly: a client feels weak, adds rice, feels slightly better because the body briefly retains more fluid, then stalls their progress for nothing. Fixing potassium directly solves the actual cause. Adding rice back just masks it temporarily while undoing the metabolic benefit of cutting carbs in the first place.
Food first, always. When supplementation is genuinely needed, I prefer potassium citrate or potassium gluconate. Both generally offer strong absorption compared to some other forms. Pairing with magnesium glycinate at night is often what actually fixes cramping and sleep quality together, more than potassium alone.
Don’t quit low carb over a preventable electrolyte shift. If cravings, fatigue, or symptoms are still derailing your progress beyond the first week or two, though, my full breakdown of why people quit low carb covers the sodium and broader electrolyte side of this in more depth.
They usually happen together, since low insulin releases both, but they show up differently. Sodium issues tend to cause headaches, fatigue, and that classic “keto flu” grogginess. Potassium issues lean more toward muscle cramps, heart palpitations, and that fluttery, anxious feeling in your chest.
Most people can with consistent effort: coconut water, avocado, leafy greens, and fish add up quickly. Supplements make sense, though, when food alone isn’t cutting it. They also help when symptoms are severe enough that you need a faster correction, ideally guided by your doctor.
Generally yes, in the 1 to 2 serving range I mentioned earlier. It does carry some natural carbs, so factor that into your daily total if you’re tracking strictly for ketosis.
With proper correction, most people feel meaningfully better within a few days, sometimes faster. Without addressing it, symptoms can drag on for a week or more, which is exactly when most people quit and blame the diet instead of the missing mineral.
Potassium isn’t optional on low carb, it’s foundational. Get it right from day one, and most of what gets blamed on “carb withdrawal” simply doesn’t happen. For the Filipino pantry staples that make this easier, browse our organic low carb store.
This article is for educational purposes only and does not replace medical advice. Anyone with kidney disease, or taking ACE inhibitors, ARBs, or blood pressure medication, should consult their physician before changing potassium intake or starting a supplement.
