Annie, this is an interesting question. I had muscle cramps on VLC/ZC, although drinking a liter of San Pellegrino nearly every day seems to resolve the issue (is it the magnesium? sodium? potassium? green glass bottle? I dunno.) Also it seemed to be worse when I was in periods of weight loss, and to ease up when my weight stabilized.

But even when I was getting the cramps regularly, the way I looked at it was this: Before going VLC/ZC, not only was I was obese, I was taking anti-depressants and anti-seizure meds, I was suffering from terrible joint pain that was interfering with even short walks, I had to use an inhaler on a daily basis -- in short, I was extremely unhealthy.

I figured then, and still do now, that whatever was causing the cramps couldn't be nearly as bad for me as asthma, depression, obesity, and autoimmunity. Of course I continued searching for a solution (like you, mag supps didn't do it for me; but why San Pellegrino seems to I have no idea, as it's got even less mg than the pills). For me, though, increasing carb intake resulted in the return of all the symptoms I listed above. So I chose the cramps as the lesser of a dozen evils.

I know that there's a group of folks who've discovered that their bodies can now "handle" carbs after a period of VLC; so far that hasn't been the case for me. If it is for you, and you can raise your carb intake without seeing a return of body fat and whatever other issues you may have had, then that's the way to go, clearly.

And if not, of course, like everyone else, I recommend you eat nose-to-tail, eat seafood, make bone broths, and generally eat as broadly as you can within your carb limit.

Finally, there are no guarantees of the long-term safety of any diet, whether it be some version of "Paleo," low-carb, high-carb, 30-bananas-a-day, or whatever. The only diet we have completely solid large-group data for is the modern western industrial diet. Those of us who don't like those results and are therefore trying something different are all voyagers, gamblers and experimenters, hanging our future hopes on what amount to best guesses, derived from the slender evidence of the past and the ambiguous experiments of the mad scientists and their chemistry sets. We might know in fifty years or so which among us chose the most wisely.

I never get muscle cramps but my husband does if he doesnt supplement. The big difference in our diets? I eat seafood and seaweed and he doesnt

Exactly, seafood is the answer. Land animals are depleted. I started eating scallops and my cramps from the all-meat diet disappeared. No such luck when I tried salt or spinach. Scallops are king, Aquatic Ape diet FTW.

My take on this is the following: If your modern version of Paleo or VLC or whatever is causing something to be deficient -- e.g. K, Mg, whatever -- it doesn't seem the optimal diet for the long term. An optimal diet should provide micronutrients w/o supplementation. If we're going to use paleo scenarios as "proof" for a diet, we have to consider all of them, no? I don't think paralyzing leg cramps (as I've personally suffered) would offer paleo humans a survival benefit!

How long have you been stricktly VLC? It takes up to 4 weeks of eating lesser then 30 g of CHO per day to get accustomed to VLC.

In our german LCHF forum muscle cramps do occur to some beginners, but in everyone who is strict for some time they are transitional.

I had them in my 2. week for some days and then they went away... I'm on VLC for 18 month now and have less then 20 g of CHO most of the time.

Do you get enough fat ~ 70% of your calories? Do you eat nose to tail? Do you include bone broth?

How much potassium are you supplementing? The 99 mg capsules are not going to cut it. I usually supplement with something like Nu-Salt when the cramps strike. One quarter teaspoon has 795 mg potassium so I take one quarter teaspoon at a time until I get relief from the cramps. Being low on the other electrolytes can also cause cramps, but my experience has consistently been that it's potassium you need on a VLC diet. YMMV of course.

This is interesting to me because in my vlc days I developed full body aches. In the morning my feet and back hurt so much that I would have trouble taking those first few steps. I was totally fat adapted - 70% of calories came from it and I was doing this for about three years. (I should add that I coupled vlc with hiit style exercise and heavy lifting which may not be ideal).

My version of vlc was prolly very low mineral as I don't love eating veggies and fruit was out because of the sugar. For a few months now I have dropped the fat and added fruits - fruit at every meal in fact. No I have not gained weight and yes those aches are gone.

I don't know if this is helpful but this is my recent n=1 experience.

The following quote is from 'The Art and Science of Low Carbohydrate Living' by Phinney & Vole:

Low carbohydrate diets don’t cause muscle cramps per se (meat and leafy greens are good sources of magnesium), but neither do they miraculously get better on low carb regimens unless the underlying problem is dealt with. This is just one more reason why leafy greens and home-made broths (good sources of magnesium) are desirable components of a healthy low carb diet.

So here’s the shortcut to ending most nocturnal or post-exercise muscle cramps. Take 3 slow-release magnesium tablets daily for 20 days. The proprietary brand-name product is ‘Slow-Mag’®, but there are a number of equally effective generics at a fraction of the brand-name price (e.g., Mag-64® or Mag-Delay®). Most people’s cramps cease within 2 weeks of starting ‘Slow-Mag®’, but you should continue to take the full 20-day course (60 tabs per bottle at 3 per day lasts 20 days). If the cramps return, do it again, and then continue taking one tab per day. If the cramps return, take 2 tabs per day. Most people can be titrated to remain crampfree by this method. Why use a more expensive slow-release magnesium preparation like Slow-Mag®? Because magnesium oxide preparations like ‘milk of magnesia’ cause diarrhea, passing through the small bowel before they can be effectively absorbed. WARNING: The only contraindication to oral magnesium supplements is severe renal failure (e.g., a GFR < 30). If you have any history of kidney problems or known loss of kidney function check with your doctor before taking Slow-Mag® or its generic equivalents.

4 years LC-VLC here, never got muscle cramps. I used to get night cramps when I was SAD, esp in the calfs, I figured out it seemed to be triggered by stress for me anyway.

I eat a lot of beef and home made bone broth daily. I eat raw hamburger weekly. Daily intake of fermented foods, home made kombucha, home made sauerkraut, some yogurt, shellfish once in a while. No caffeine, rarely drink tea, drink mineral water once in a while.

I do supplement erratically, but it seems that most supplements are not readily bio available so we may actually only absorb 50% of a given dose, or they are sold on combinations that are antagonistic such as magnesium/calcium combo these two can interfere with each other in absorption.

Mg needs fat to be bio-available. Try a higher priced product if you are shopping generic. Too much magnesium causes diarrhea, so just cut back a bit when you begin to have runny stool. That will be the appropriate level for your body's needs. Also, being at normal weight, you can still have a heavy metal toxicity, a natural detox can help. And, misalignments in the pelvis, knees, feet can contribute also. Try chiropractic.