This patient support community is for questions related to juvenile diabetes including
Celiac disease,
depression, diabetic complications, hyperglycemia /
diabetic keto-acidosis,
hypoglycemia, islet cell transplantation,
nutrition, parenting a diabetic child, pregnancy, pump therapy, school issues, and teens with
diabetes.
I myself am a 25year old who is fairly active in sports too. I have reactive hypoglycaemia & suffer those exact same episodes sometimes daily sometimes. The first thing to say would be that there are many things that can cause hypoglycaemia, ranging from Addisons Disease to hormonal problems & thyroid problems. These were all negative in my case, but the next step after diagnosis should be a dietician. You say you tried to stabilise it through diet but did not elaborate, so this may or may not be of use.
As for it being the syptom (symptom) of something else, if you searach on the english Google, there are some good medical journals published which list all the areas to look into.
I hope this is of help