This is a very similar situation to mine. From what you've said, it seems possible that you may have reactive hypoglycaemia. Unfortuately, this is probably better termed a syndrome, rather than a disease - and it's one you may struggle to either prove conclusively, or get a doctor to recognise - especially if you're in the UK.
If you are RHG, the hot feeling is caused either by excess production of insulin, or by the adrenal reaction as your body drags itself out of low blood glucose levels. Over a period of time, this can lead to adrenal fatigue.
You can self-test with a personal BG meter to get a better idea what's going on with your blood sugar. To do this, you need to test hourly over a 4-5 hour period after drinking 410ml of Lucozade from fasting 1st thing in the morning (NHS 2 hour tests are completely useless, as reactive hypo will give a completely normal reading at 0 and 2 hrs). Before doing this however, it's probably wise to speak to your doctor and to have standard diagnostic tests carried out for diabetes and thyroid function, as the glocuse load could be dangerous if you are diabetic and hyperthyroidism or late onset/autoimmune diabetes can cause similar symptoms.
If you are genuinely reactive hypo, there's no cure as such, but avoiding large intakes of carbohydrate will help, as will eating 6 small meals a day, rather than regular larger meals. There's also a lot to be said for supplementing with zinc and B complex vitamins, but this needs to be done carefully, as excessive zinc intake can cause other problems with copper imbalance, etc.
I would also say that, in my opinion, I believe that RHG is most likely a symptom of the body's endocrine system starting to fail. Careful management of your diet may well prevent the condition progressing into diabetes - but, equally, it may be an inevitable outcome so, even if you do test clear of diabetes at the moment, regular occasional blood glucose monitoring is probably advisable so that you can seek medical guidance if anything does appear to be changing.
You may find these sites useful:
http://www.hypoglycemia.asn.au/
http://hypoglykemie.nl/
...and just for the record, I'm in no way medically qualified, so please research all of the above to form your own conclusions. I've just spent a lot of time researching this subject just lately!
Dominic