You need salts as well as liquids, VitD(I would test for it it if you cramp often), and magnesium.
You can get a lot of salts and mag from Bananas. The greener they are, the less of their carbs you can digest, so you can avoid some carbs by simply choosing a more green banana.
I often start the day with a banana for breakfast and some coffee. I often eat eggs. Eggs are great in every aspect If you exercise, and the cholesterol isn't an issue if you are not at risk.
I take 5K IU/125mcg vitD per day, and 10K after matches, but I always test very low for VitD in my blood. My body simply does not absorb it according to my blood tests. But, more to the point, your average person does not absorb it much, either. My doc suggest for your average person 2-3K/day every day.
If I do not have 10K after a match, I will occasionally cramp. I used to just deal with it until they became debilitating in work. I finally got tested and came up super low in VitD.
Now if I dose and thrown in a banana, I almost never cramp.