Sugary Snacks Are Secretly Fueling a Dementia Epidemic—Find Out How Many May Be at Risk!

Recent studies reveal a stark reality about aging in America: while people are living longer, many are not enjoying good health in their later years. According to a scientific study published in JAMA, the average life expectancy in the U.S. is now 80.7 years for women and 74.1 years for men. Alarmingly, the country has the largest gap between healthspan—the number of years spent in good health—and lifespan. A significant contributor to this issue is dementia, with the National Institutes of Health estimating that 42% of Americans over the age of 55 will eventually develop this debilitating condition.

But here's a silver lining: a 2024 report published in The Lancet suggests that an estimated 45% of dementia cases could be preventable through dietary and lifestyle changes. It’s increasingly clear that our everyday habits hold considerable sway over our long-term health, particularly brain health. Experts have identified a common afternoon habit that could be silently increasing dementia risk without many people realizing it.

The Afternoon Habit That Could Increase Dementia Risk

When those afternoon cravings strike, many of us reach for something sugary. However, consuming sugary snacks during this time could elevate your risk for dementia. According to registered dietitian Julie Andrews, who specializes in the MIND diet—a nutritional plan designed to lower dementia risk—there is significant scientific evidence linking a high-sugar diet to increased dementia risk, particularly in the afternoon. “Studies show that large fluctuations in blood glucose levels over time—both highs and lows—can damage blood vessels in the brain, cause inflammation, and prevent brain cells from receiving the fuel they need to function properly,” Andrews explains.

Dr. Alvaro Pascual-Leone, a professor of neurology at Harvard Medical School and chief medical officer at Linus Health, elaborates that chronic instability in blood sugar levels can adversely affect brain function. He notes that a high-sugar diet may lead to brain insulin resistance, essentially a condition where brain cells cannot utilize glucose effectively. This could pave the way for memory loss and dementia, a phenomenon being informally termed “type 3 diabetes.”

“Unstable or high blood sugar may contribute to damaging blood vessels, including the small ones that nourish the brain,” Dr. Dung Trinh, chief medical officer at Healthy Brain Clinic, states. “It’s linked to oxidative stress, which can injure brain cells and disrupt their energy usage, given that glucose serves as the main fuel for the brain.”

Beyond blood sugar regulation, Kelli McGrane, a registered dietitian and author of "MIND Diet for Beginners," warns that sugar can also disturb the brain’s reward system. “While moderate sugar intake isn't usually troubling, consistent high sugar consumption can overstimulate this system, negatively affecting learning, memory, mood regulation, and even motivation,” she notes.

Why the Afternoon Matters

Blood sugar spikes from sugary snacks taken in the afternoon can be particularly detrimental for brain health, according to Pascual-Leone. This is due to the body's natural glucose intolerance being lower in the latter half of the day, resulting in more pronounced spikes in blood sugar levels. Both Andrews and Pascual-Leone emphasize that consuming sugar in the evening can also hinder sleep quality. Insufficient sleep, in turn, is known to elevate dementia risk.

Pascual-Leone highlights the importance of sleep as a protective mechanism against dementia, noting that it’s during sleep that the brain clears out neurotoxic proteins. If these proteins, specifically beta-amyloid and tau, are not eliminated, they can disrupt communication between neurons, which is closely linked to dementia.

You might wonder if all sugary foods pose the same risk to brain health. Not quite. According to the experts, snacks like cookies and candies, which are laden with refined sugars and flours, can spike blood sugar levels quickly and offer little nutritional benefit. In contrast, whole fruits, which come packed with fiber, vitamins, and antioxidants, are absorbed into the bloodstream more slowly, thereby minimizing blood sugar spikes. Trinh mentions that fruits not only help regulate blood sugar but also provide nutrients essential for protecting brain cells.

Strategies for Healthier Snacking

While recognizing the connection between sugar consumption and dementia risk, experts agree that completely eliminating sugar is neither necessary nor practical. Pascual-Leone emphasizes the importance of pleasure in food for overall mood and brain health. Instead of cutting sugary snacks out entirely, he advocates for moderation and savoring those treats.

To mitigate blood sugar spikes when indulging in sweets, Andrews recommends pairing sugary snacks with high-fiber or high-protein foods. “Consuming sugar alone is a primary cause of blood sugar spikes and subsequent crashes, so it’s beneficial to combine it with foods that balance blood glucose levels,” she advises.

It’s also wise to snack proactively rather than reactively. Dr. Trinh explains that when blood sugar levels drop—such as after skipping meals—you’re more inclined to reach for quick, sugary fixes that are often low in nutritional value. Regularly consuming balanced meals and snacks can make it easier to make healthier choices.

If you do choose to enjoy a sugary treat, earlier in the day is better to minimize adverse effects. For healthier alternatives, Trinh and McGrane recommend dark chocolate, which is rich in cocoa flavanols known to support healthy blood flow in the brain, as well as berries and nuts, which are convenient and packed with brain-boosting nutrients.

The overarching message from experts is clear: while a diet high in sugar increases the risk of dementia, it doesn’t necessitate a complete sugar ban. Watching your intake and pairing sugary treats with nutritious options can help you enjoy these indulgences without compromising your brain health. After all, moderation and mindfulness in eating are key to a happier, healthier life.