from what I understand cheese is full of calcium, and too high a calcium:magnesium ratio = constipation. Nuts, seeds and vegetables are full of magnesium, so maybe that is why some low-carbers get constipation if eating too much cheese and not many veggies?

In my experience, several things get things moving - magnesium tablets/solution, fish oil and making sure the diet is really high in fat.

I have read that animal fats are very much needed for absorption of minerals, but are in themselves not good sources (well, of magnesium in particular - they are very good sources of zinc and selenium for example). Also drinking water is probably a factor - if soft water is being drunk then more minerals from diet are needed.

Nutritiondata.com told me I would get around 100mg Mg a day from an all animal product diet. That seems very low. Calcium on the other hand can easily come out at nearly a gram with the addition of cheese.

I would obviously like to believe that we don't need any more Mg than this and that it is just fine to have low levels - but I've read too much stuff, and experienced too much pms/depression without extra Mg to buy into it all so easily.

You'll forgive my being a little doubtful bear - I don't mean to offend as I think it's good evidence you've done so well for so long 'all meat' - I just want to do the best thing for my bod.