welcome to hcm
your question is not clear. by diet controlled hypoglycemia
do you mean you are diabetic but with your diet control you are able to keep your blood sugar levels under control. occasionally leading to hypoglycemic episodes.
correct me if my interpretation is incorrect.
to donate a kidney
there are lot of other parameters that need to be examined by a physician. they include your age, general health, bp , other associated diseases, blood tests.
so based on your sugar related episodes it is difficult to say whether or not you can donate.
hope this is helpful