What does “my diet is good” mean exactly? How many servings per day/week are you getting of nuts, seeds, meats, veggies? Just curious if you care to elaborate…
I would as well presume the cramps to be due to low potassium and or magnesium. You may absorb these poorly, and or sweat a lot. You lose a lot through sweat even if you do absorb well. There is NO downside to too much magnesium (up to 5 grams per day) as long as you dose up to it slowly. You’ll notice loose stools as you approach your max, but you can back off to reduce this. Start with 500mg supplemental and increase from there. The loose stool thing is much worse with cheap forms of magnesium. Look for chelated, glycinate, citrate, aspartate, etc - although zma won’t work well because it would lead to zinc overdose at the higher end. B6 and boron increase magnesium absorption.
Low potassium is usually also accompanied by muscle weakness, but you also lose a lot in sweat.
Could be low sodium if you tend to avoid high/sodium containing foods.
Then again it could be low calcium, but this isn’t as common in lifters who don’t shy away from whey/dairy, unless you have corresponding low vitamin d levels which enables proper calcium utilization.
Do you have any twitching?
Some B vitamins affect utilization and retention of minerals.