Rates of diabetes have increased dramatically in America since the 1970’s, and today approximately 100 million Americans have prediabetes1. Nowadays, diabetes is nearly synonymous with type 2 diabetes, since 90-95% of cases have a metabolic rather than an autoimmune cause2.
A big gap remains between the science of diabetes and general clinical practice and food advice. Many people misunderstand the relationships between diabetes, blood sugar, insulin resistance, and food. I’ve talked with many patients who have even gotten questionable advice from their doctors about what to eat. This two-part blog aims to clear up some confusion by discussing the metabolic causes of type 2 diabetes, food options for treating (and preventing) it, as well as the roles of body weight and carbohydrate intake.
Despite decades and billions of dollars spent, misunderstandings about diabetes may persist because there is a difference between what we use to test diabetes and what actually causes the disease. Blood sugar is by far the most common test, but it has major limitations. Blood sugar doesn’t cause diabetes—it is basically just a marker. While it is true that damage can eventually happen to organs like the kidneys and retinas after prolonged exposure to (very) high blood sugar, it is not even close to the main killer for diabetics either. Much more often, people with diabetes die from some other health problem, like stroke, heart attack, fatty liver, cancer, or dementia, which are all much more common in diabetics than the general population3,4,5. We’ve known these risks for many years, but common approaches to treat diabetes strangely don’t take them into account. If the vast majority of diabetics’ health problems are from maladies that have little to do with blood sugar, then why would we mainly want to pay attention to blood sugar?
An informative way of looking at blood sugar is more as a symptom than a cause – similar to how a fever is a symptom of a bacterial infection. For example, a fever might cause damage if it gets extreme, but a doctor wouldn’t just lower a patient’s temperature while allowing deadly bacteria to multiply throughout their body, right? A good doctor would treat the cause of the infection. Yet, we take this treat-the-symptom approach all the time with blood sugar and diabetes.
The most direct cause of type 2 diabetes is metabolic changes from a buildup of fat inside the vital organs and muscle tissue6. This, in turn, leads to chronic inflammation and a higher risk of many different diseases. This type of fat is often dubbed “visceral”, and is fundamentally different from the fat naturally stored for energy just beneath our skin. The buildup of fat inside our organs can cause lots of different health problems, and insulin resistance and diabetes is just one of them. Insulin resistance happens when insulin receptors effectively become “deaf” to the hormone insulin. Normally, insulin is released by the pancreas after a meal and insulin receptors tell organs to let sugar in to power the body’s cells. During insulin resistance however, sugar is not let in (as much), even when insulin levels are high, and blood sugar eventually rises too much.
Fortunately, we can treat inflammation and insulin resistance together! I have personally witnessed hundreds of people reduce their diabetes medications and insulin over just a few weeks time, mainly through diet. What is good at reducing inflammation and visceral body fat is good for blood sugar levels, insulin resistance7, and many other things in the body, so we can give people more health benefits than just reducing their blood sugar.
Certain diets can be misleading because they can lower blood sugar without improving inflammation or insulin resistance. That is, certain diets can change the symptoms but not the cause. If doctors are mainly following blood sugar & A1c, then they won’t necessarily know if insulin resistance or inflammation, (or heart disease risk, or many other things) are actually improving. For example, if blood sugar is going down, it could just be because there’s less sugar available (from, say, a low-carb diet), or that the body is healing and using carbs better, or both. Some high-fat, low-carb diets lower blood sugar but increase inflammation8. Lots of health messaging suggests that metabolic function must be better whenever high blood sugar decreases, but the opposite can be true when people eat lots of saturated fat9, (e.g. those found in coconut oil, palm oil, butter, cheese, and beef); people actually become more insulin resistant.
