I wanted to lose some weight and tried the low carbohydrate diet and lost lots but a side bonus my restless legs is gone. If I eat too many carbs they come back.
I found this site http://www.mlists.net/judson/Elaty.html that mentions that too much insulin (which is caused by carbs) can aggrevate RLS. Carbs also can cause high blood pressure, high tryglicerides, high LDL as well as diabetes.

Anyway I can attest that reduction of carbs to about 50 grams a day keeps my RLS in control.