Steve Blake, Doctor of Science, Nutritional Biochemistry

By Steve Blake, Doctor of Science, Nutritional Biochemistry

We cannot reverse type 2 diabetes by only restricting sugar and using medications. Clearly, this has not worked: 37 million Americans have diabetes and 96 million have pre-diabetes. The cause of type 2 diabetes is not just too many fast-releasing “carbs.” Diabetes can result from insulin resistance due to excess dietary saturated fats that keep sugar in the bloodstream.[i]

Let’s think about what happens when we eat a sweet dessert. When a lot of glucose (sugar) hits our bloodstream, we feel energized! This excess sugar must be removed from the blood to prevent damage to our blood vessels, eyes, kidneys, and brain.

What does insulin do?

In our pancreas, we have beta cells that produce insulin when blood sugar is high. The insulin then travels to cells and locks onto insulin receptors. This triggers the cells to take sugar out of the bloodstream. The excess sugar is quickly gone from the blood and goes into our cells and all is well—if we do not have insulin resistance. Insulin resistance is when insulin in the bloodstream does not effectively lower blood glucose.

Insulin also tells liver cells to stop making blood sugar. When the liver also has insulin resistance, increased from excess dietary saturated fats, the liver cannot “see” the insulin and continues putting sugar into the blood. This contributes to high fasting blood sugar. Fasting blood sugar is measured before breakfast in the morning or many hours after a meal.

Excess dietary saturated fats create insulin resistance that keeps blood sugar high. In one study, after eating one breakfast high in saturated fats, blood glucose increased by 55%—from an average of 130 mg/dL to an average of 201 mg/dl.[ii] A high saturated fat diet can increase insulin resistance in just 3 days.[iii] In just one day of eating excess saturated fats (42 grams), whole body insulin resistance was created in all subjects. Insulin resistance persisted overnight and was relieved by one day on a low saturated fat diet.[iv] A breakfast with 30% of calories from saturated fat (versus a healthy 6%) in 100 students raised blood sugar 50% (77 to 118 mg/dL) in just four days, even though the dietary sugar went up only 7%.[v] Women were given less than half a cup of heavy cream as a source of saturated fats (25 grams). Insulin resistance was increased in all women.[vi]

Which foods have excess saturated fat?

The main sources of excess saturated fat for many people are cheese and butter. A study followed over 7,000 people for 6 years. Those who ate more saturated fat from butter, cheese, and meat doubled their risk of diabetes (hazard ratio 2.19).[vii] Many people get excess saturated fats from meat. Meat increased diabetes risk in women 26% per serving, and processed meat increased diabetes risk 73% per serving.[viii]

Many vegan food products are made with coconut oil. Coconut oil is made up of about 90% saturated fats. The three most dangerous saturated fats are lauric acid, myristic acid, and palmitic acid—these make up 65% of coconut oil. Unlike short-chain saturated fatty acids, these fatty acids increase the risk of insulin resistance in diabetes, as well as increasing risk of cardiovascular disease. One way that these three saturated fats increase risk of diabetes and heart disease is through their effect on cell membranes which results in fewer locations for insulin receptors and for receptors for low-density lipoproteins (LDL). This leads to higher levels of blood glucose and LDL-cholesterol.

How much saturated fat is too much?

How much saturated fat is too much? The American Heart Association recommends that less than 6% of calories be obtained from saturated fats. This comes out to 12 grams of saturated fat daily on an average 1,800 calorie diet. This maximum of 12 grams per day is not always easy to achieve even on a plant-based diet. Healthy foods like avocados, chocolate, and nuts can easily contribute 4 or 5 grams of saturated fat daily. One raw food diet I analyzed contained 15 grams of saturated fat in a day, mostly from nuts and seeds. This diet had 2,274 calories, so the 6% limit was 15 grams. Even a single tablespoon of coconut oil contributes 11.2 grams of saturated fat.

How do saturated fats increase blood sugar?

One way that excess saturated fats increase blood sugar is by reducing the number of insulin receptors in cell membranes by up to half. With fewer receptors for insulin, blood sugar stays higher. This leads to more oxidative damage and less energy production for muscles, thinking, and other needs. Cell membranes with excess saturated fats have fewer places for insulin receptors. Also, insulin receptors are broken up and fewer of these insulin receptors are created with higher dietary saturated fats.[ix]

Higher dietary saturated fatty acids interfere with the signaling between the insulin receptor and the glucose transporter-4. Glucose transporter-4 is needed to get blood out of the bloodstream and into the cell. This reduces the amount of blood sugar that can enter the cell and increases the risk of high blood sugar.

Saturated fats can kill off insulin-making cells

Excess saturated fats can kill off beta cells that make insulin. Animal fats, the chief source of saturated fats in American diets, increase circulating levels of free saturated fatty acids. The beta cells that produce insulin in the pancreas can die off when there are excess free saturated fatty acids (30-60% decrease in beta cells). There are then fewer beta cells to make insulin.[x] It is easier to reverse diabetes before too many beta cells are damaged. Even though many beta cells can no longer make insulin, by reducing saturated fat and excess calories, some beta cells can become active again and make insulin.[xi]

Antioxidants are protective against diabetes damage

The damage to blood vessels, eyes, the brain, and kidneys from high blood sugar in diabetes is largely caused by free radical oxidation. High blood sugar can damage proteins in the blood—including hemoglobin. The leading measure of diabetes is glycated (sugar-damaged) hemoglobin (HbA1c). Eating lots of fresh fruit, vegetables, and beans helps provide antioxidants to protect us. Whole fruit, but not fruit juice, reduces risk of diabetes[xii] while protecting against oxidative diabetes damage. Glycemic load measures how much a serving of a food will raise blood sugar. Those foods with a glycemic load under 10 raise blood sugar little. Berries are low in glycemic load (strawberries are 3.6) and have lots of antioxidants. Nuts and seeds provide antioxidant vitamin E to protect us.

Slow grains and fiber

Even with low saturated fat, we need to avoid fast carbohydrates, like white flour, white rice, and sugar. Brown rice or steel-cut oats are examples of “slow” grains that can be included. Beans provide nice slow-releasing carbohydrates to keep blood sugar stable. Fiber from whole plant foods is helpful to slow the release of sugar from foods into the bloodstream.

What about fats and oils?

Dietary fats can be helpful or harmful. Flaxseed powder contains the essential omega-3 alpha-linolenic acid. This can help with blood sugar control. Trans fats are to be avoided and are even worse than saturated fats. Although industrial trans fats are largely banned in the United States, they are still used in many other countries. Did you know that trans fats are found in beef and cheese as well as in some processed foods?

We need to reduce excess saturated fats to reverse diabetes

We can improve our ability to reduce high blood sugar levels. We need to reduce meat, cheese, and other sources of high amounts of saturated fat. We need antioxidants from berries and other low glycemic load fruits, along with vegetables, beans, and nuts. We need this approach to avoid and reverse diabetes.

To learn more about saturated fat and diabetes

Diabetes Breakthrough: The Key to Insulin Resistance by Steve Blake. Also see my textbook Fats and Oils Demystified to learn more about fats and oils. Each is available for $9.95 for the e-book version at https://drsteveblake.com/index.html .The scholarly paper, How excess dietary saturated fats induce insulin resistance, is free at: https://papers.ssrn.com/sol3/Delivery.cfm/SSRN_ID3959396_code4470654.pdf?abstractid=3959396&mirid=1.

[i]Blake SM and Rudolph D. How excess dietary saturated fats induce insulin resistance. Int J Transl Sci. 2021 Nov 9;1(1):104.

[ii]Koska J, Ozias MK, Deer J, Kurtz J, Salbe AD, Harman SM, Reaven PD. A human model of dietary saturated fatty acid induced insulin resistance. Metabolism. 2016 Nov 1;65(11):1621-8.

[iii]Bachmann OP, Dahl DB, Brechtel K, Machann J, Haap M, Maier T et al. Effects of intravenous and dietary lipid challenge on intramyocellular lipid content and the relation with insulin sensitivity in humans. Diabetes. 2001 Nov 1;50(11):2579-84.

[iv]Parry SA, Woods RM, Hodson L, Hulston CJ. A single day of excessive dietary fat intake reduces whole-body insulin sensitivity: the metabolic consequence of binge eating. Nutrients. 2017 Jul 29;9(8):818.

[v]Attuquayefio T, Stevenson RJ, Oaten MJ, Francis HM. A four-day Western-style dietary intervention causes reductions in hippocampal-dependent learning and memory and interoceptive sensitivity. PLoS One. 2017 Feb 23;12(2):e0172645.

[vi]González F, Considine RV, Abdelhadi OA, Acton AJ. Saturated fat ingestion promotes lipopolysaccharide-mediated inflammation and insulin resistance in polycystic ovary syndrome. The Journal of Clinical Endocrinology & Metabolism. 2019 Mar;104(3):934-46.

[vii]Guasch-Ferré M, Becerra-Tomas N, Ruiz-Canela M, Corella D, Schroeder H, Estruch R et al. Total and subtypes of dietary fat intake and risk of type 2 diabetes mellitus in the Prevención con Dieta Mediterránea (PREDIMED) study. The American journal of clinical nutrition. 2017 Mar 1;105(3):723-35.

[viii]Fung TT, Schulze M, Manson JE, Willett WC, Hu FB. Dietary patterns, meat intake, and the risk of type 2 diabetes in women. Archives of internal medicine. 2004 Nov 8;164(20):2235-40.

[ix]Dey D, Mukherjee M, Basu D, Datta M, Roy SS, Bandyopadhyay A, Bhattacharya S. Inhibition of insulin receptor gene expression and insulin signaling by fatty acid: interplay of PKC isoforms therein. Cellular Physiology and Biochemistry. 2005;16(4-6):217-28.

[x]Cnop M. Fatty acids and glucolipotoxicity in the pathogenesis of Type 2 diabetes. Biochemical Society Transactions. 2008 Jun 1;36(3):348-52.

[xi]Taylor R. Banting Memorial Lecture 2012 Reversing the twin cycles of Type 2 diabetes. Diabetic medicine. 2013 Mar;30(3):267-75.

[xii]Muraki I, Imamura F, Manson JE, Hu FB, Willett WC, van Dam RM, Sun Q. Fruit consumption and risk of type 2 diabetes: results from three prospective longitudinal cohort studies. BMJ. 2013 Aug 29;347.

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