None of the calorie-replacement stuff I've tried has near enough magnesium or calcium to keep me from cramping when I'm sweating heavily (which is most of the time ). That's how they get you. I bring Endurolytes on a long ride or run, in addition to whatever sports drink or gels (or solid food on a ride). Plus I'll take additional calcium/magnesium morning and evening - double or triple my maintenance dose of 333 mg each per day.

I'm pretty close to gauging how much I'm sweating and having my dosages figured out.