We know that diabetes is a disorder of the metabolism, that is, derangement in the way the body uses digested food for growth and energy. Type-1 diabetes is an autoimmune disease and there isn’t much that we can do about it to prevent it. On the other hand, Type-2 diabetes is the most common form of diabetes and is often associated with older age, obesity, physical inactivity, and family history of diabetes, and we can do a lot to prevent or manage it. If diabetes is unchecked it can have long term complications that affect almost all parts of the body. It can lead to cardiovascular disease, stroke, kidney failure, blindness, and even neuropathy and foot ailments.
Many researches, one of them being a clinical trial by Diabetes Prevention Program launched by National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK), have shown that people can lower their chances of developing Type-2 diabetes through diet and regular exercise. As far as diet is concerned, a large number of researches found that Mediterranean diet may be useful in patients with newly diagnosed Type-2 diabetes or in people who have high risk of developing Type-2 diabetes. 
Oldways, the Harvard School of Public Health, and the European Office of the World Health Organization introduced the classic Mediterranean Diet along with a Mediterranean Diet Pyramid graphic in 1993 at a conference in Cambridge. According to them, the Mediterranean diet includes the following:
• Abundance of food from plant sources including fruits and vegetables, potatoes, whole grain cereals and millets, nuts, and seeds.
• Olive oil as principal fat, replacing other fats and oils including butter and margarine.
• Daily consumption of low to moderate amount of cheese and yogurt.
• Consumption of low to moderate amounts of fish and poultry twice a week and only 340-450 gm of red meat per month.
• 1-2 glasses of wine per day, normally with meals. However, this is optional from a contemporary public health perspective.
It has actually been demonstrated that people living in Mediterranean areas such as Greece or Southern Italy have much lower rates of diabetes and heart disease than in other countries, say, the US or India.
The inclusion of olive oil in the diet for diabetes might come as a surprise. Now, aren’t all oil supposed to be bad for diabetes? Well, no. Olive oil and canola oil are the exceptions and olive oil is by far the better of the two. There are basically three kinds of dietary fats in oils – saturated fat (bad fat), polyunsaturated fat (bad fat), and monounsaturated fats (good fat). Monounsaturated fat is the predominant dietary fat found in olive oil and it is healthy because it is rich in antioxidants such as vitamins and iron. The benefits of antioxidants are well known and need not be repeated here.
Although a tablespoon of olive oil has about 120 calories, it is still a heart healthy and diabetes friendly fat. For example, a meta-analysis of high monounsaturated fat diets for patients with diabetes has shown that these diets improve lipoprotein profiles as well as glycemic control. High monounsaturated fat diets reduce fasting plasma triacylglycerol and VLDL-cholesterol concentrations by 19% and 22%, respectively, and cause a modest increase in HDL-cholesterol concentrations without adversely affecting LDL-cholesterol concentrations. Furthermore, the study found no evidence that high-monounsaturated-fat diets induced weight gain in patients with diabetes when the energy intake was controlled.
This is how the monounsaturated fats in olive oil work – The monounsaturated fats in olive oil stimulate secretion of a hormone called Glucagon-like peptide-1 (GLP-1). The GLP-1 is an intestinal peptide hormone that stimulates the beta cells in the pancreas to secrete more insulin. GLP-1 secretion is lower than normal in people with Type-2 diabetes. What olive oil does is it improves the secretion of GLP-1 which in turn improves glycemic tolerance in diabetic patients.
Normally a high carbohydrate diet leads to belly fat and belly fat is in turn associated with weight gain and insulin resistance. Another invisible but highly dangerous effect of high carbohydrate diet is the drop in adiponectin levels. Adiponectin is a hormone that is secreted by adipose cells (fat cells). It helps improve insulin sensitivity and regulates sugar as well as fat metabolism. Low blood levels of adinopectin are associated with risk of heart attack. Researchers found that diet rich in olive oil improved insulin sensitivity and prevented drop in adinopectin and accumulation of belly fat.
You may have noticed that the classic diabetic diet is low in carbs and very low in fat. And those who follow this diet or those who are on weight reducing mission are aware that fats are very satisfying to eat and it’s pretty hard to stick to low carb-low fat diets for long. So, inclusion of certain amount of olive oil works great to eliminate the cravings you can get when going in for fat-free diets. Besides, you get the benefits of improved insulin sensitivity, lower risk of heart attack, and no belly fat. Some studies also suggested that dietetic virgin olive oil intake should be initiated before puberty and maintained through life to get the full benefit.
* Some of the research studies on how olive oil benefits diabetes:
1. http://www.bmj.com/cgi/content/full/bmj.39561.501007.BEv1
2. Rodríguez-Villar C, Pérez-Heras A, Mercadé I, Casals E, Ros E. Comparison of a high-carbohydrate and a high-monounsaturated fat, olive oil-rich diet on the susceptibility of LDL to oxidative modification in subjects with Type 2 diabetes mellitus. Diabet Med 2004; 21: 142-149.
3. Garg A. High-monounsaturated-fat diets for patients with diabetes mellitus: a meta-analysis. Am J Clin Nutr 1998; 67: 577S-582S
4. Perez-Jimenez F, Alvarez de Cienfuegos G, Badimon L, Barja G, Battino M, Blanco A, et al. International conference on the healthy effect of virgin olive oil. Eur J Clin Invest 2005;35:421-4.
5. Rocca AS, LaGreca J, Kalitsky J, Brubaker PL. Monounsaturated fatty acid diets improve glycemic tolerance through increased secretion of glucagon-like peptide-
