【Young People, Take Note】Is Your Smartphone Causing Early Memory Problems? The Truth About “Digital Dementia” and Habits That Protect Your Brain

“Dementia? Isn’t that something only older people get? It has nothing to do with someone young like me, right?”

If that’s what you’re thinking, hold on a moment.

A growing number of research reports suggest that “early-onset dementia (young-onset dementia)” is on the rise among people in their 20s and 30s.

And what’s behind it isn’t some distant, abstract problem.

It’s overusing the smartphone you can’t put down, and snacking or eating late at night over and over again.

The everyday habits so many of us share are slowly but steadily wearing down the brain.

In this article, I’ll explain exactly how smartphones and late-night eating put young brains at risk, and walk you through concrete steps you can take starting today.

Smartphones Are Eroding Young Brains! The Serious Problem of “Digital Dementia”

The Frontal Lobe Shrinks! How Smartphone Dependence Changes the Structure of the Brain

Recent research has shown that long hours of smartphone use can change the very structure of the brain.

The area most affected is the part called the “frontal lobe.”

The frontal lobe is the brain’s most important region, in charge of judgment, emotional control, and organizing memories.

You may have heard the term “digital dementia.”

Keep in mind from the start, though, that this is a concept popularized by a book, not an official diagnosis.

It refers to a sharp decline in memory and concentration caused by over-dependence on smartphones and digital devices.

In other words, the kind of cognitive decline normally seen in middle age and beyond is showing up early in young people who overuse their smartphones.

One of the things that got me started with fasting was how strangely sluggish my thinking had become at work.

Back then, I was on my phone or computer for more than 8 hours a day, and I could no longer pull my thoughts together when speaking up in meetings.

I still remember worrying that this wasn’t just tiredness, that “maybe my brain is actually changing.”

How Notifications, Scrolling, and Short Videos Steal Your “Focus”

Social media and video apps are designed to serve up “the next piece of content” one after another.

As this repeats, the brain develops only the “circuits that react to short bursts of stimulation,” and gradually loses the ability to keep thinking about something for a long time (deep thinking).

If it continues, memories stop sticking, almost as if your brain had aged, and “Wait, what was I about to do?” becomes an everyday occurrence.

The Labels “Digital Dementia” and “Smartphone Dementia”

Online and on TV, you may come across terms like “digital dementia” or “smartphone dementia.”

These describe a state in which forgetfulness and poor concentration appear from overusing smartphones and computers, but they are convenient labels for easy understanding, not official medical diagnoses.

No doctor will diagnose you with “digital dementia,” and it should be considered separate from forms of dementia such as Alzheimer’s disease.

Because the term is so striking, be careful not to fall into the misunderstanding that “using a smartphone gives you dementia.”

The Link Between Smartphones and Young-Onset Dementia Isn’t Yet Understood

At this point, there is no clear evidence that smartphone use directly causes young-onset dementia.

What long-term effects smartphone overuse has on the brain is still being studied.

So there’s no need to jump to the conclusion that “I’ll get young-onset dementia because I look at my phone” and worry yourself sick.

On the other hand, it is also true that, depending on how you use it, a smartphone can tire out your brain and disrupt your sleep and eating habits.

If those disrupted habits continue for a long time, we can’t rule out the possibility that they will affect your brain health in the future.

Temporary Forgetfulness Caused by “Brain Fatigue”

One thing that commonly happens with smartphone overuse is a state called “brain fatigue,” in which the brain becomes exhausted from constantly processing information.

The brain sorts the information coming in and puts what it needs away on the shelves of memory.

But when news, social media, and videos keep pouring in, it can’t keep up with the sorting, and it ends up like cardboard boxes piled high in front of the shelves.

As a result, symptoms such as not being able to recall someone’s name, forgetting what you were about to do, and being unable to stay focused become more likely.

Forgetfulness caused by this kind of brain fatigue differs greatly from progressive dementia in that it can be expected to recover with rest and a review of your lifestyle habits.

That said, don’t judge for yourself; if the symptoms drag on, please consult a medical professional.

Why Late-Night Eating and All-Day Grazing Can Speed Up Alzheimer’s

Blood Sugar Spikes Damage Brain Cells

Do you have a habit of eating ramen late at night or munching on snacks in the small hours?

At night, your body is in “energy-saving mode,” so the carbohydrates you take in from food tend to raise your blood sugar sharply.

This rapid rise and fall in blood sugar (a blood sugar spike) is known to do significant damage to the brain’s nerve cells.

When blood sugar spikes happen again and again, the cells of the hippocampus (the part of the brain that handles memory) gradually become damaged.

The buildup of a protein called “amyloid beta,” which is characteristic of the brains of people with Alzheimer’s disease, is also said to be closely linked to excessive sugar intake.

I explain the link between sugar and dementia risk in more detail in this article as well.

→ “Too Much Sugar Doubles Dementia Risk!? An Alzheimer’s-Prevention Diet“

Insulin Resistance Leads to “Insulin Failure in the Brain”

Some researchers even go so far as to call Alzheimer’s disease “type 3 diabetes.”

A lifestyle with lots of late-night eating and snacking is one of the biggest factors that accelerate insulin resistance.

If this habit continues from a young age, your brain will certainly age faster.

For more on how the all-day grazing habit affects the brain, please also read The Frightening Way All-Day Grazing Throws Off Your Brain Chemistry.

Late-Night Eating Throws Off Blood Sugar and Body Weight

When you stay up late, you get hungry and find yourself reaching for chips, instant cup noodles, and sugary drinks.

Because you’re less active at night, what you eat late is more easily stored as fat, which also tends to lead to weight gain.

On top of that, late-night snacks centered on sweets and carbohydrates make your blood sugar shoot up and crash, putting a strain on the body.

If this way of eating continues for years, the risk of lifestyle-related diseases such as obesity, diabetes, and high blood pressure will steadily rise.

And diabetes and high blood pressure are known factors that raise the risk of dementia.

I explain the link between eating too much sugar and dementia in detail in another article as well, so please use it as a reference.

The Worst Combination Common Among Young People: “Smartphone + Late-Night Eating”

Eating While Looking at Your Phone Causes “Overeating” and “Brain Damage” at the Same Time

Plenty of people eat their meals while looking at their phones, don’t they?

In fact, this does double damage to the brain.

The first is the risk of “overeating.”

When your attention is on your phone, fullness signals have a harder time reaching your brain, so you end up eating too much.

The second is that “your memory of the meal weakens.”

Because the brain doesn’t record the meal as an “experience,” you’re more likely to feel hungry again after eating.

Blue Light at Night Raises Cortisol and Harms the Brain

When you look at your phone at night, the blue light from the screen enters through your eyes and tricks your brain into thinking “it’s still daytime.”

This triggers the release of the stress hormone “cortisol” and suppresses melatonin, which helps you fall asleep.

Chronically high cortisol is known to shrink the brain’s hippocampus.

Fiddling with your phone on a sleepless night, then eating a late-night snack out of vague hunger.

This combination is the vicious cycle that damages young brains most efficiently.

I used to fall into exactly this pattern myself.

I’d eat chips while watching YouTube in the middle of the night, and then for days on end I couldn’t get up feeling refreshed and my head was foggy in the morning.

Looking back, that was a pretty bad habit.

Using Your Phone Before Bed Cuts Into Your Sleep

Many people probably find themselves still looking at their phones after getting into bed.

As with the blue light I mentioned earlier, the bright light of the screen is said to trick the brain into thinking “it’s still daytime” and delay the release of the hormone that promotes sleep.

On top of that, the stimulation from social media and videos keeps your mind wired, which can make it harder to fall asleep and leave your sleep shallow.

Sleep is thought to be like a “nightly cleaning time” for the brain, when it clears away the day’s waste.

When you keep missing sleep, this cleaning isn’t done properly, and your brain’s fatigue carries over into the next day.

“Distracted Eating” Leads to Overeating

As I touched on earlier, when you eat while looking at your phone, it becomes hard to pay attention to what and how much you’re eating.

You become less aware of the signals that you’re full, so you often end up eating too much.

Some of you have probably had the experience of watching a video and suddenly realizing you’d emptied a whole bag of snacks.

Smartphones, staying up late, and late-night eating all pull one another in, forming a combination that easily creates a vicious cycle that brings on both sleep deprivation and overeating at the same time.

Rethinking them as a set, rather than one at a time, is the shortcut to protecting your brain.

Watch Out for Morning Phone Use and Skipping Breakfast Too

The morning after a late night, it’s easy to fall into a pattern of sleeping until the last minute, skipping breakfast, and checking your phone the moment you wake up.

If you stare at a screen without getting any morning light, your body clock is said to have a harder time resetting, making it harder to feel sleepy even at night.

Also, if you skip breakfast and then binge at lunch, your blood sugar swings wildly, and you’re more likely to feel strong drowsiness and sluggishness in the afternoon.

When you wake up, try opening the curtains first to let in the sunlight, and only look at your phone after you’ve gotten ready for the day.

Once your morning rhythm is in order, you’ll naturally get sleepy at night, making it easier to break out of the vicious cycle of staying up late and eating late.

What Is Young-Onset Dementia? The Basics of Dementia That Begins Before Age 65

Young-Onset Dementia Is “Dementia That Develops Before Age 65”

Young-onset dementia is an umbrella term for dementia that develops before the age of 65.

It’s not the name of one specific disease; it refers to cases of dementia, from a variety of causes, that begin at a younger age.

Dementia has a strong image as a disease of older people, but it can also occur in people in the prime of their working lives.

The average age of onset varies by survey, but many sources put it at around the 50s;
onset in the 20s or 30s is still rare in terms of numbers, but in recent years reports among younger generations have been increasing.

In other words, teenagers and people in their 20s who use their smartphones a lot don’t need to immediately worry too much about young-onset dementia.

The Most Common Causes Are Alzheimer’s Type and Vascular

Alzheimer’s-type dementia is thought to be a disease in which unneeded protein “waste” builds up in the brain and gradually damages nerve cells.

With vascular dementia, damage to blood vessels from high blood pressure, diabetes, abnormal blood lipids, and the like is a major risk, so it’s fair to say it is closely tied to lifestyle habits.

Difficulties Unique to Young-Onset Dementia

Because young-onset dementia strikes the generation that is working, raising children, and supporting the household finances, it tends to have a very large impact on daily life.

It’s also not unusual for both the person and those around them to assume “they’re still young” or “they’re just tired,” so seeing a doctor gets delayed.

It can be mistaken for depression or menopausal symptoms, and it’s said that in some cases it takes a long time to reach a diagnosis.

That’s exactly why it’s important to consult a specialized medical facility early if you notice any worrying changes.

Noticing early tends to broaden your options for treatment and support.

Early Signs of Dementia That Are Easy to Miss

It’s Not Just “Forgetfulness”! Subtle Changes Typical of Young People

When people hear “early dementia,” many probably picture “not being able to remember things” or “names not coming to mind.”

But in younger generations, the first signs to appear are a little different.

These are easy to dismiss as “just being tired,” but if they persist or progress, you need to be careful.

For more on constant eating and cognitive decline, please also read “Early Cognitive Decline Is Surging! How a Nonstop-Eating Lifestyle Damages the Brain.”

Young-Onset Dementia Can Occur Even in Your 30s and 40s

According to research by Japan’s Ministry of Health, Labour and Welfare, the number of people with young-onset dementia (onset before age 65) is estimated at more than about 35,000.

The average age of onset is said to be about 51, but cases in people in their 30s and 40s are on the rise.

A notable feature is that, in addition to genetic factors, lifestyle habits are often heavily involved.

If you notice early and take action, the chances of slowing or halting its progression rise significantly.

Changes Often Seen in Young-Onset Dementia

In the early stages of young-onset dementia, changes may appear that go beyond forgetfulness, such as no longer being able to plan out work or household tasks smoothly.

It’s said that family members or coworkers often notice these changes before the person does.

How It Differs From Forgetfulness Caused by Brain Fatigue

Forgetfulness caused by brain fatigue is typically marked by “taking a while to remember” or “being able to remember with a hint.”

Forgetfulness caused by dementia, on the other hand, is said to tend toward forgetting the experience itself entirely.

For example, not being able to recall what you had for dinner yesterday happens often enough just from tiredness.

But if you don’t remember having eaten dinner at all, that may be a sign that calls for attention.

Another difference is that brain fatigue tends to improve once you rest well or step away from your phone, whereas dementia progresses little by little.

See a Doctor Early in Cases Like These

If forgetfulness or poor concentration continues for several months or more and is interfering with your work or daily life, please see a medical professional early.

Options include memory clinics, neurology, and psychiatry, and starting by talking to your regular doctor is also one way to go.

There are also consultation services for young-onset dementia in many areas, so try not to carry this alone as a person or a family.

Sometimes conditions that cause dementia-like symptoms, such as depression, sleep disorders, or thyroid disease, are discovered.

Even if you think “it’s probably just my imagination,” getting it checked will give you peace of mind.

What Family and the People Around You Can Do

With young-onset dementia, the person may have trouble noticing the changes, or may not want to admit them.

When family members or coworkers notice a change, try gently asking, “Have you been feeling tired lately?” rather than blaming or interrogating them.

When suggesting a doctor’s visit, too, inviting them with “Let’s get your health checked once” is likely to be more readily accepted than saying “You might have dementia.”

In the workplace, talking with the company doctor or HR may make it possible to adjust how they work.

Rather than carrying it alone, facing it together with the people around them should help give the person peace of mind.

Smartphone Habits, Food, and Sleep That Protect Your Brain

Put Down Your Phone One Hour Before Bed

The first thing to work on to protect your brain is cutting down on phone time before bed.

Ideally, put your phone down one hour before bed and don’t bring it into the bedroom.

If you use your phone as an alarm, simply getting a separate alarm clock can stop you from mindlessly scrolling in bed.

Try changing your pre-bed time to something that relaxes your mind and body, such as reading, stretching, or a lukewarm bath.

Cut Back on Notifications to Let Your Brain Rest

Every time a phone notification interrupts what you’re doing, your brain has to reset its focus.

It’s like trying to tidy your desk while new documents keep arriving one after another.

Make Time to “Do Nothing”

A lot of people automatically open their phones while waiting for the train or during breaks, don’t they?

But the brain is thought to organize information and lock in memories during the time you spend zoning out.

If you fill every spare moment with information, the brain loses its time to sort things out.

Make a conscious effort to build time to gaze at the scenery or take a walk without looking at your phone into your day.

It’s also a good idea to use your phone’s Screen Time feature to check how much you’re actually using it.

Once you can see it as a number, it becomes easier to notice when you’re overdoing it.

Rethink Your Relationship With Social Media Too

When you scroll through social media, you can end up feeling down after comparing yourself with other people’s happy-looking posts.

This kind of emotional fatigue also quietly builds up as stress on the brain without you realizing it.

When stress continues, your sleep gets lighter and you crave sweets, which also makes it easier for your lifestyle habits to fall apart.

Try setting your own rules, such as muting accounts that wear you out or limiting yourself to opening social media just a few times a day.

A smartphone is a handy tool, so it’s important to keep in mind that you should “master it” rather than “be used by it.”

You don’t have to quit completely; simply deciding when and where you use it can make a big difference in how tired your brain gets.

Key Points for Brain-Friendly Eating

To protect your brain health, it’s important to eat in a way that doesn’t throw your blood sugar out of balance.

Go easy on sugary snacks, juice, and meals of nothing but white bread or noodles, and combine vegetables, fish, soy products, mushrooms, seaweed, and the like.

The omega-3 fatty acids in oily fish and the antioxidants in vegetables and fruit are drawing attention as nutrients that support brain health.

If you make a point of “vegetables first,” eating vegetables or soup at the start of a meal, it becomes easier to prevent sharp blood sugar spikes.

Help Your Brain Clean Itself With Sleep and Exercise

Going to bed and getting up at the same time every day helps you secure your brain’s “nightly cleaning time.”

Rather than catching up on sleep on your days off, keeping the same wake-up time on weekdays and days off makes it easier to keep your body clock in order.

Aerobic exercise such as walking is also thought to improve blood flow to the brain and help keep it healthy.

Exercise also helps prevent lifestyle-related diseases, so it’s an important habit for lowering your risk of dementia as well.

Stop Late-Night Eating and Create a Fasting Window

If you’re going to rethink your late-night eating habit, I recommend paying attention to the stretch of time without food from dinner to the next morning.

For example, just deciding not to eat after 8 p.m. lets your digestive system rest while you sleep and makes it easier to keep your blood sugar steady.

Once you’re used to it, adopting intermittent fasting, which limits the hours you eat, is another option.

Research on how fasting periods affect the brain is moving forward in many directions, and it can be useful as a habit that prevents mindless grazing.

However, growing teenagers, people who are very underweight, and people with chronic conditions should not create long fasting periods on their own judgment.

Talking With People and Hobbies That Use Your Head Matter Too

To keep your brain healthy, it’s said that connections with other people and activities that use your mind are important, not just physical habits.

Activities like meeting and talking with family and friends, learning new things, and enjoying hobbies such as playing an instrument, cooking, or crafts give your brain a healthy amount of stimulation.

Passively scrolling through information on your phone and spending time thinking for yourself or working with your hands use the brain in completely different ways.

Try making a point of setting aside time for face-to-face conversation, not just exchanges on a screen.

I also cover the link between fasting and the brain in detail in a related article.

Frequently Asked Questions About Early Dementia, Smartphone Dependence, and Late-Night Eating

To Protect Your Young Brain, Start Changing Your Habits One at a Time, Today

To sum up what I’ve covered, there are three main points for protecting a young brain.

On top of that, by adopting 16-hour fasting (intermittent fasting),
you can expect autophagy (the cells’ self-repair function) to be activated, which also helps clear out the brain’s waste (amyloid beta).

It’s been two years since I started fasting, and the foggy feeling I had in my late 30s has truly cleared up.

I can really feel that my focus and memory have improved.

For specific methods and benefits of fasting, be sure to check out my complete guide to intermittent fasting.

If you’d like to make fasting easier to stick with, try using supplements that support fasting as well.

Get Along Well With Your Smartphone and Start Protecting Your Young Brain Today

Young-onset dementia is dementia that develops before the age of 65, and while onset in the 20s or 30s is still rare in terms of numbers, it’s by no means someone else’s problem.

“Digital dementia” and “smartphone dementia” are not official diagnoses, and it hasn’t been shown that smartphones directly cause young-onset dementia.

Even so, habits such as using your phone before bed, staying up late, and eating late at night tend to lead to brain fatigue, sleep deprivation, and a higher risk of lifestyle-related diseases.

Try starting with small habits like putting your phone down one hour before bed, not eating after 8 p.m., and walking a little every day.

And when forgetfulness or mistakes at work continue for a long time, don’t forget to consult a medical professional instead of worrying about it alone.

Changing how you spend today, even a little, should help protect your brain 10 and 20 years from now.

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