there are two types of diabetes. types 1 and 2.
first you have to learn how insulin affects the body. insulin is produced from the pancreas when the stomache signals it to. (when you eat) when you eat, your stomache changes food into glucose, and using beta cells, the amount of food you take in effects the desired amount of insulin for your body to produce. it's basically a balancing act. the insulin is needed for cellular exchange of nutrients. mainly glucose into the cell from the blood stream.
type 1 (hypoglycemia) is a decreased level of insulin released or produced by the pancres when the stomach signals it. so glucose goes into the blood, but little or no insulin. resuling in increased glucose floating around in your blood and not in the cell, resulting in dehydration, weight loss, fatique, etc.
type 1 normally occurs in people under the age of 20. but can occur at any age. there are a lot of signs for type 1. Shaking and confusion, rapid breathing, fruity smell to the breath, abdominal pain, loss of consciousness are considered emergency signs and should be looked at right away.
type 2 (hyperglycemia) is the result of the body not recognising the insulin excreted by the pancreas. you will have excess inslulin and glucose levels, but the insulin is inaffective. this occurs more commonly in older, and more obese people. type 2 is passed down genetically as well, so if it runs in the family, it's possible.