When a headline shouts that a “popular drink raises stroke risk by 300% and dementia by 290%,” it’s hard not to feel a jolt of fear—especially if that drink is in your fridge right now. A US brain doctor, Dr. Clint Steele, has recently warned that diet soda may dramatically increase the risk of stroke and dementia, echoing earlier research that linked artificially sweetened beverages with brain health problems.


In this guide, we’ll gently unpack what those big percentages really mean, how solid the science is as of late 2025, and—most importantly—what you can realistically do if you love your zero-sugar drinks but also care about your brain and heart health.


Person holding a can of diet soda with brain illustration in background
Diet sodas are marketed as healthier because they contain no sugar, but research is raising questions about their effects on the brain and blood vessels.

What’s the Drink and Where Does the “300% Stroke Risk” Claim Come From?

The drink in question is diet soda and other artificially sweetened soft drinks—the “zero sugar,” “diet,” or “light” versions of popular sodas and energy drinks. Dr. Clint Steele’s warning aligns with concerns raised over the last decade, especially from large observational studies.


The widely cited figures—a 3-fold (300%) increase in stroke risk and nearly a 3-fold (290%) increase in dementia risk—trace back to findings like those from the Framingham Heart Study, published in 2017 in the journal Stroke. That research found that people who consumed at least one diet drink per day had a much higher rate of stroke and dementia than those who rarely or never drank them.


“Our findings suggest that artificially sweetened beverages may not be a healthy alternative to sugar-sweetened drinks, especially for brain health.”
— Adapted from Pase et al., Stroke, 2017


What Does “300% Higher Risk” Actually Mean for You?

Huge percentages can sound terrifying, but it’s important to understand the difference between relative risk and absolute risk.


  1. Relative risk (300%) means the risk is three times higher in one group than another.
    If 1 in 100 people in the low-intake group had a stroke, and 3 in 100 in the high-intake group had a stroke, that’s a 300% relative increase—but an absolute increase of 2 extra cases per 100 people.
  2. Absolute risk is the actual chance you’ll be affected. Your personal risk depends on age, blood pressure, smoking, cholesterol, diabetes, family history, physical activity, and overall diet—not just what you drink.

So, a tripling of risk in research is a serious red flag, but it doesn’t mean diet soda guarantees stroke or dementia. It does mean that, for many people, daily consumption is probably not worth the potential risk, especially if you already have cardiovascular or metabolic risk factors.


What Does the Latest Science Say About Diet Soda, Stroke, and Dementia?

As of late 2025, the evidence around artificial sweeteners and brain health is still evolving. Here’s a balanced summary:


  • Large observational studies (like the Framingham Heart Study and others in the US and Europe) have repeatedly found that people who drink diet beverages daily have higher rates of:
    • Ischemic stroke
    • Dementia, including Alzheimer’s disease
    • Metabolic syndrome and type 2 diabetes
  • Brain imaging studies have shown associations between high intake of artificially sweetened drinks and smaller brain volume or changes in areas involved in memory, though these findings are still under active investigation.
  • Randomized controlled trials (the gold standard) are more mixed and often short term. Many focus on weight and blood sugar, not long-term brain outcomes, and typically don’t last long enough to measure stroke or dementia.
  • In 2023–2024, WHO and several national health agencies reviewed the safety of common sweeteners like aspartame and acesulfame-K. Most concluded they are “safe within acceptable daily intakes,” but also acknowledged signals of possible risk for:
    • Cardiovascular events
    • Type 2 diabetes
    • All-cause mortality in large cohorts

“When several large, independent studies point in a similar direction, we have to pay attention—even if we don’t yet have perfect proof of causation.”
— Neurology & Public Health Commentary, 2024


How Could Diet Soda Affect the Brain and Blood Vessels?

We don’t have a single clear mechanism, but researchers have proposed several plausible pathways:


  1. Metabolic confusion Artificial sweeteners may disrupt how the body responds to sweetness, potentially:
    • Altering insulin release
    • Changing appetite and cravings
    • Promoting weight gain or central fat in some people
    Over years, this can influence diabetes and vascular risk.
  2. Gut microbiome changes Several sweeteners can alter the balance of gut bacteria. Emerging evidence links these shifts to:
    • Inflammation
    • Insulin resistance
    • Blood vessel dysfunction
    All of which can affect brain blood flow.
  3. Vascular health and small vessel disease Chronic intake may contribute indirectly to high blood pressure, stiff arteries, or blood clotting abnormalities—key drivers of ischemic strokes and vascular dementia.
  4. Behavioral compensation People may think, “I had a diet soda, so I can eat more,” unintentionally increasing their intake of processed foods and unhealthy fats, which can damage both heart and brain over time.

Infographic-style illustration of brain, heart and blood vessels
Brain and cardiovascular health are closely linked. Anything that harms blood vessels can increase stroke and dementia risk over time.

A Real-Life Example: Cutting Back Without Feeling Deprived

A 52-year-old office manager—let’s call her Maria—came to a brain health clinic after her sister had an early stroke. Maria didn’t smoke, but she had high blood pressure and drank 3–4 cans of diet cola every day, often instead of water.


She felt stuck: diet soda helped her stay awake at work, and she worried that switching to regular soda would ruin her blood sugar and weight. Working with her clinician, she:


  • Gradually cut down by one can every two weeks
  • Swapped one can for sparkling water with lemon
  • Moved another can to earlier in the day, then replaced it with herbal tea
  • Started tracking headaches and energy; within a month, her energy dips became less severe

After three months, she was down to one diet soda every other day. She hadn’t become a “perfect eater,” but she’d meaningfully reduced a potential risk factor while improving hydration and blood pressure—changes that likely help her brain longer term.



Diet Soda vs. Regular Soda vs. Healthier Drinks: A Practical Comparison

Many people feel forced to choose between diet soda (with artificial sweeteners) and regular soda (with large amounts of sugar). In reality, both have drawbacks, and there are better middle paths.


Glasses filled with different colored sodas and water for comparison
Both sugary and artificially sweetened sodas carry potential health downsides. Gradually shifting toward water-based drinks is usually safest for long-term brain and heart health.

  • Regular soda
    • High in sugar and calories
    • Strongly linked to obesity, type 2 diabetes, fatty liver, and heart disease
    • Also associated with poorer brain health over time
  • Diet soda
    • Low or zero calories
    • May aid short-term weight loss when replacing sugary drinks
    • But repeatedly linked to higher risks of stroke, dementia, and metabolic issues in some studies
  • Healthier alternatives
    • Water (plain, sparkling, or infused with fruit or herbs)
    • Unsweetened tea or coffee (in moderation)
    • Occasional drinks lightly sweetened with small amounts of sugar or natural sweeteners

From a brain and heart standpoint, most experts now suggest using both sugary and diet sodas as occasional treats, not daily staples.


Step-by-Step: How to Safely Cut Back on Diet Soda

If you’re drinking diet soda daily, sudden cold-turkey quitting can trigger headaches, irritability, or intense cravings—mostly from caffeine withdrawal and habit disruption. A gradual, compassionate approach works better.


  1. Track your baseline for one week Write down:
    • How many diet drinks you have
    • When you drink them
    • What you’re doing or feeling before you reach for one (tired, stressed, bored)
  2. Set a realistic first goal Examples:
    • If you drink 4 cans/day, aim for 3 cans/day for the next 2 weeks.
    • If you drink 1 large bottle, replace ¼–½ of it with water or tea.
  3. Introduce go-to replacements Keep alternatives within easy reach:
    • Sparkling water with a squeeze of citrus or a splash of 100% juice
    • Unsweetened iced tea (add mint or a slice of fruit)
    • Herbal teas for late afternoon or evening
  4. Manage caffeine separately If you rely on diet cola for caffeine, consider:
    • Replacing some cans with black or green tea
    • Gradually lowering total caffeine instead of stopping instantly
  5. Reassess every 2–3 weeks Ask yourself:
    • “Can I comfortably cut one more serving?”
    • “Is there a time of day that’s easiest to change?”
    Adjust slowly based on your answers.
  6. Celebrate progress, not perfection Even cutting from 2 cans a day to 2–3 per week is a meaningful reduction in potential risk exposure.


Who Should Be Most Cautious with Diet Soda?

While it’s wise for most people to limit artificial sweeteners, certain groups may want to be extra careful with daily diet soda:


  • People with a personal or family history of stroke, vascular dementia, or early heart disease
  • Those with high blood pressure, diabetes, or prediabetes
  • Individuals who are overweight or have central obesity
  • Anyone drinking several servings of diet beverages every day

Doctor discussing health risks with a middle-aged patient
If you already have risk factors for stroke or dementia, talk with your healthcare provider about how diet soda fits into your overall risk profile.

For healthy adults with low overall risk who drink diet soda only occasionally, current evidence does not prove that rare consumption is dangerous. The concerns are primarily about habitual, long-term daily intake.


What Do Experts Recommend Right Now?

Neurologists, cardiologists, and public health bodies increasingly converge on a cautious but practical stance toward diet sodas and artificial sweeteners:


  • U.S. and European heart associations encourage limiting both sugary and artificially sweetened beverages, prioritizing water and unsweetened drinks.
  • The World Health Organization (WHO) has advised against using non-sugar sweeteners as a primary tool for long-term weight control, citing potential risks and uncertain benefits over time.
  • Many neurologists now suggest that people at high risk for stroke or dementia should treat diet soda as a “sometimes” drink at most.

“From a brain health perspective, our safest bet is to keep both sugar and artificial sweeteners low, and base our hydration on water, tea, and other minimally processed drinks.”
— Preventive Neurology Clinic Perspective, 2025

Common Obstacles—and How to Overcome Them

If you’ve tried to quit or cut back on diet soda before, you may have run into one or more of these roadblocks:


  • “Water is boring.” Experiment with:
    • Infusions: cucumber, mint, lemon, lime, berries, or ginger
    • Temperature: ice-cold sparkling vs. room-temperature still
    • Glassware: a favorite bottle or glass can surprisingly make a difference
  • “I need the caffeine buzz.” Try:
    • Switching some servings to tea or smaller coffees
    • Gradually stepping down total caffeine to avoid withdrawal
  • “It’s my treat or stress relief.” Replace the ritual, not just the drink:
    • Short walk outside
    • Five deep breaths away from your desk
    • Herbal tea in a mug you love
  • “I don’t want to gain weight by switching to sugary drinks.” You don’t need to trade diet soda for full-sugar soda. Focus on:
    • Water-based drinks with minimal added sugar
    • Portion control when you do have something sweet


Your 7-Day Brain-Friendly Drink Makeover (Simple Action Plan)

If you want to respond to the headlines without panicking, here’s a gentle, one-week reset you can start today:


  1. Day 1–2: Log what you drink, no judgment.
  2. Day 3: Replace one diet soda with sparkling water or unsweetened tea.
  3. Day 4–5: Move one diet soda earlier in the day and replace a later one with a non-caffeinated drink.
  4. Day 6: Try going half a day without diet soda and notice how you feel.
  5. Day 7: Decide on a realistic weekly “budget” (for example, up to 3 cans per week) and plan when you’ll enjoy them most.

Refreshing glass of sparkling water with lemon slices
Simple swaps—like sparkling water with citrus—help you cut back on diet soda while still enjoying something fizzy and satisfying.

A Balanced Take: Don’t Panic, but Do Pay Attention

Diet soda has long been marketed as the “guilt-free” answer to sugary drinks. But accumulating evidence—including the kind highlighted by Dr. Clint Steele and earlier large studies—suggests that daily, long-term use may carry real risks for stroke and dementia, especially in people who already have cardiovascular or metabolic risk factors.


You don’t need to be perfect, and an occasional diet soda is unlikely to make or break your brain health. Yet shifting your everyday habits toward water, unsweetened tea, and minimally sweetened drinks is one of the simplest, most powerful ways to support your brain and blood vessels over the long run.


If you’re concerned about your personal risk, especially with a family history of stroke or dementia, consider talking to your doctor about:


  • Your current diet soda or artificial sweetener intake
  • Your blood pressure, cholesterol, and blood sugar levels
  • Other modifiable risk factors: exercise, sleep, smoking, and stress

Today, you could start with just one small change: swap one can, log your drinks, or set a simple weekly limit. Your future brain—and heart—are likely to thank you.


Further Reading and Reliable Resources

For more detailed, up-to-date information on artificial sweeteners, stroke, and dementia risk, explore: