Insulin and insulin resistance explained. Insulin resistance occurs when higher and higher levels of insulin are required to maintain normal healthy blood sugar levels. High levels of insulin are inflammatory, it locks up fat stores so fat cannot be used by the body, it is an appetite stimulant, has a growth hormone effect, increases the risk of cancer and is associated with an increased future risk of dementia. These are enough to make it highly undesirable! It is often undetected and not found by standard health screening.