Don’t lose your hard-earned muscle tone—keep those guns flexing with spinach. (One study found that the nitrates it contains might make muscles stronger.) But this veggie is a superfood for tons of reasons, and it also packs the most magnesium per serving (163 mcg per cup). Magnesium helps maintain normal muscle and nerve function, and has also been shown to help regulate blood sugar and blood pressure, says Grotto. If you suffer from digestive issues such as Crohn’s disease or frequent vomiting or diarrhea, you might not be absorbing enough of this nutrient. Sure, spinach is a great salad base, but this leafy green actually delivers the most magnesium when it’s canned or cooked.