Insulin resistance is widely agreed to be the primary cause of the epidemic of type two diabetes. Researchers with very different opinions regarding what is to be done about it generally agree that the problem is insulin resistance. Promoters of the Mediterranean diet, as well as low-fat high-carbohydrate diets and high-fat/protein low-carbohydrate diets will all point to insulin resistance as the defect they are trying to correct.
New research has shown that a major part of insulin resistance is mediated by a lipid molecule called ceramide. For many decades it was thought to only be a building block of cell membranes and not biologically active. The membrane function was to keep the borders between cells and their environments stable. We now know it is also a signaling molecule that activates metabolic pathways in the liver.
Ceramide is chemically a kind of wax. When I was in medical school, I learned a fancy word for ear wax: cerumen. Cerumen and ceramide have the same root word, and ear wax is about twenty percent ceramide. However we now know that ceramides also circulate in the bloodstream and elevated levels of ceramide are associated with insulin resistance.
Your body can obviously make its own ear wax, so it can make this molecule all by itself, but when you consume foods high in saturated fat like butter, palm oil, coconut oil or lard, the liver uses the saturated fat to make ceramide. Worse, it also stimulates the liver to make more ceramide from whatever molecules are currently available for use.
So if you are diabetic, your insulin resistance will continue for as long as you are getting any substantial calories from saturated fat. Even lean people who eat a diet full of butter and brie will have some insulin resistance, even if it isn’t full blown type two diabetes.
Anyone who is truly serious about reducing insulin resistance must (dramatically) reduce the saturated fat content of their diet. To get adequate calories, that saturated fat must be replaced with starchy plant foods. Potatoes, sweet potatoes, corn, peas, beans, lentils, rice and whole grains are the best choices in the world. People who subsist on diets composed primarily of these starches have very low rates of diabetes and the arterial disease that goes along with it.