The Not-So-Sweet News About Sugar’s Effects on the Brain

Wellness

The basics about sugar’s role in declining cognition and long-term brain health.

by | Aug 27, 2025

PHOTO VIA ADOBE STOCK

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The average American consumes approximately four times as much sugar as nutritionists recommend, and that may be a conservative estimate. Given the grim statistics about the rise in chronic illnesses, many of which may be linked to what we eat, that’s probably no surprise. But did you know that added sugars not only impact our waistlines and health outcomes, but can also have profound effects on the ways our brain work?

“We know that when people who have pre-diabetes or diabetes consume more simple sugar, their blood sugar level is affected,” says registered dietician Tama Rodriguez, who hosts classes on the topic at Eisenhower Health in Rancho Mirage. “[They may have] higher levels of glucose in their blood, and those higher levels over time have effects on cognitive development, have effects on increasing the aging of cells in the brain. We know that elevated blood glucose levels make a difference.”


When people who have pre-diabetes or diabetes consume more simple sugar, their blood sugar level is affected. … Those higher levels over time have effects on cognitive development.”

— Tama Rodriguez, dietician


If you’re eating too much refined or added sugar, there’s a good chance you’re not eating enough fiber, protein, and healthy fat. The bottom line? Rodriguez recommends that you make sure you acquire less than 10 percent of your calories from sugar. If you’re scanning nutrition labels, look for added sugars, and remember that every 4 grams of added sugar equals approximately 1 teaspoon.

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