There are unfortunately quite a number of things that can cause dizziness as you say apart from Hypoglycaemia/diet and inner ear infection/disorder. High blood pressure or low blood pressure is one of the main ones, especially on standing up.
But there are also many viruses that have this affect. There are many medications that cause dizziness. There are also medical conditions such as Parkinson's Disease that can also cause dizzy spells.
Within the blood, a low oxygen level is often the cause of dizziness as is anaemia. Many people who suffer from depression and/or anxiety also experience dizzy spells. And the list goes on. But when you feel dizzy often you have been experienceing other symptoms. If this is the case then take a note of them and ask your health care practioner for advice.