Hi Nat!
Sorry to hear about the cramp! Straight magnesium is a natural muscle relaxer. The added calcium is great but I think that is there to lighten the effects of the magnesium as it can "digest too quick!" - among other reasons. I am sure your diet is great - how is your intake of Dark leafy greens? You may need more potassium. - Which as you know is in the vegetables. I also like "E - Mergency" It is a powdered vitamin C supplement that is fizzy when you add it to water. I use it after my weight trainings and it replaces electrolytes etc... They do make a no sugar one. Hope this helps. IMHO you are probably burning sooo many calories that you are sweating out some of the nutrients you need. I also find that when I drink my water I get light headed because I flush out so much potassium. ? Again, hope this helps!