Excess dietary fats, alcohol, salt, soft drinks and coffee, as well as excess sweating, stress, heavy periods and some pharmaceuticals may all decrease your magnesium levels. Magnesium is found in a number of dietary sources including leafy green vegetables, legumes, cacao, almonds, cashews, walnuts and brazil nuts, sea vegetables, pumpkin seeds, coriander and parsley, whole grains. Magnesium is important when exercising as it may help reduce muscle tension and cramps and support body recovery.