insulin resistance, a form of metabolic dysfunction that
increases inflammation and fat storage. (I’ll describe exactly
how this affects the brain in upcoming chapters.) That our
bodies become confused when high amounts of saturated fat
and carbohydrates are consumed together should not come
as a surprise. After all, you would have a hard time finding
foods in nature that contain both saturated fat and
carbohydrates. Fruit is mostly pure carbohydrate and fiber,
and low-sugar fruits like avocado and coconut contain
ample fat but very little carbohydrate. Animal products are
usually pure fat and protein. And vegetables, whether
starchy or fibrous, are usually free of fat. Dairy would be the
one exception, where saturated fat and sugars are combined
—which may help it serve its evolutionary purpose of
helping a young animal put on weight. Otherwise, only
modern foods regularly marry saturated fat and
carbohydrates, combined usually with the intent of
promoting overconsumption.
SATURATED FATS IN YOUR BLOOD
Blood levels of saturated fat have been linked with
increased risk for dementia, but how do those fats get there
in the first place?^34 “It is commonly believed that circulating
fatty acids reflect dietary intake, but the associations are
weak, especially for SFA (saturated fatty acids),” wrote
researchers from Ohio State University in PLOS ONE,
seeking to answer this very question.^35 They found that two