The 2-to-1 calcium-to-magnesium ratio (2:1) was
first suggested by the French magnesium researcher
Jean Durlach5 as a high limit not to be exceeded, when
he warned against excessive calcium relative to magnesium
intakes; that is, one’s calcium intake from all
sources including food, water and supplements should
not exceed one’s total magnesium intake by more than
2 parts calcium to 1 part magnesium on a weight basis.