A meter that measures the level of β-hydroxybutyrate in your blood serum is considered the most accurate indicator of ketosis. But I have to warn you the strips are not cheap. Most meters are capable of measuring serum glucose, as well, by using a different strip.
Not necessarily. Metabolic damage accumulates over a period of years, and a lot of people learn that they are Type II diabetics only when their serum glucose gets out of control. But almost all of them were noticeably insulin-resistant for years or even decades prior to diagnosis.
Type I diabetes is hard to miss, though, since you will be continually thirsty and craving sugar, as well as wasting away. Go to YouTube and search on the name Troy Stapleton, for the experience of someone who suddenly became Type I diabetic at age 40. He is an Australian radiologist and, being a doctor, recognised the symptoms right away, but he talks about what to look for.
Type I diabetes is an autoimmune disease, in which the body kills off the insulin-secreting cells of the pancreas. Type II diabetes is the result of metabolic damage. Type III diabetes is metabolic damage to the brain, and is better-known as Alzheimer’s disease.