Cramps, esp in your legs, calves, feet at night (of all the inconvenient moments) can come from potassium or magnesium depletion. Do you work out or do cardio on those days also? Maybe consider a potassium pill (e.g. 99 mg). Are you taking a good multivitamin with your diet? Definitely include that. Sweet potatoes and bananas are a good source of potassium also.
One of the drawbacks of following a "strict" diet is that sometimes some of the nutrients that would come from a widely varied diet end up getting left out. Thus the need for a good multi. But sometimes, you still end up short. Maybe add 3 oz of sweet potatoe to your dinner and see if that helps. Also make sure that you are drinking lots of water!
Was also going to say, remember that you are hitting your body with a new thing -- a different way of eating, possibly more restricted than its used to. Plus hitting the gym -- make sure you give you body enough time to adjust to these changes. And drink LOTS of water! Dont' deprive your body because it will let you know if its missing something. The purpose of good diet & training is give you more energy from fueling yourself and burning that fuel optimally -- not running yourself down. Let yourself recover sufficiently from training as well (diet + training + RECOVERY!!!!!) and maybe include some l-glutamine in your diet to aid that recovery as well.