Sustainable Living Center Oregon
Apart from the well-documented benefits, the ketogenic lifestyle provides, like weight loss, lower blood sugar and blood pressure, and improved cardiovascular risk factors … people commonly report sharper thinking. Brain fog disappears.
There isn’t much published scientific research explicitly studying the effects of ketosis on brain function in healthy humans outside the epilepsy world, so we can’t say for sure that keto is “good” for the brain. However, we do have a good idea of what’s not good for the brain: chronically high blood sugar and insulin.
Type 2 diabetes and high blood pressure—two conditions rooted in high blood sugar and/or insulin—are among the risk factors for Alzheimer’s disease (AD). In fact, researchers now regularly call AD “type 3 diabetes,” and you might also come across the term “brain insulin resistance.”
The links between metabolic syndrome and cognitive impairment are so strong that researchers also use the phrase “metabolic-cognitive syndrome.”
AD is called “type 3 diabetes” because the primary problem in the brain of someone with AD is that neurons in affected regions of the brain are no longer metabolizing glucose properly. They’re starving for fuel.
Millions of people have normal blood glucose (a.k.a. blood sugar) levels, but very high insulin, and having chronically high insulin—even when blood sugar is normal—is a major risk factor for AD.
This is independent of family history or genetics: if you have high insulin most of the time, you have an increased risk for developing AD. According to one study, compared to people with normal insulin levels, those who had high insulin but who were not diabetic had double the risk of developing AD.
People with higher blood glucose had worse cognition than people with lower glucose, and this was probably due to changes in the physical structure of the brain.
Alzheimer’s is only the most severe manifestation of the adverse effects of chronically high blood sugar and insulin on the brain. What about when things are in a much milder state? Could this be what we casually call brain fog?
When your blood sugar fluctuates wildly throughout the day, it’ll reach some big highs and drop to some precipitous lows. Nervousness, anxiety, confusion, and difficulty speaking are some of the brain-related effects of acute hypoglycemia (low blood sugar).
So if chronically high blood sugar negatively influences cognition, then it’s possible that keeping blood sugar within a healthy range could have a protective influence. It’s a safe bet that you’re better off having regular blood sugar and insulin levels than chronically high levels of either.
Friends and family may have peppered you with arguments about the brain “need carbs,” or perhaps a medical or nutrition professional even warned you that your brain would starve on a low-carb diet because the brain needs 120 grams of glucose every day.
Your brain needs glucose. There’s no denying that. But a need for glucose doesn’t equate to a need for lots of sweet and starchy carbohydrates in your diet.
One of the things your body is great at making out of many different raw materials is glucose. You can make glucose from amino acids (from protein), glycerol (from fats).
The brain is an energy hog. Sources differ, but as a general ballpark, your brain represents only about 2% of your body weight, but it sucks up nearly 20% of your body’s energy.