For nearly 35 years, I have studied how you can use neuroplasticity to boost your brain. Once you understand how the brain works, you can make it run at a much higher level.

Here is the most exciting thing I have learned. Your brain is not fixed. It changes every day based on what you do with it.

I like to picture the brain as a forest with trails. Every time you learn something new, you make a small trail, what we call a neuronal pathway. Walk that trail again and again, and it becomes a wide road. Stop walking it, and the grass grows back, and the trail fades.

In neuroscience, we say use it or lose it.

Your brain grows when you challenge it

This is not a hypothetical. We can see new pathways and more brain volume on MRI scans when people of any age challenge their brains.

When London taxi drivers memorize 25,000 streets, the hippocampus, the memory center, becomes visibly larger. When college students study a foreign language intensely for three months to work as interpreters, the hippocampus grows. When college students, and in a separate study older adults, learn to juggle for three months, the parts of the brain for hand-eye coordination grow.

When they stop practicing for three months, those newly grown areas shrink back toward their starting size.

What do these activities have in common? They are new. They are challenging. They make you work a little. Novelty plus effort is fertilizer for your brain.

What happens when you scroll

When you scroll through Instagram or TikTok, your brain is busy, but it is not challenged.

Each video lasts a few seconds and asks nothing of you. You get a quick reward for no effort at all. You are not building new trails, and the pathways for attention and complex thinking fade, because you are not using them.

We are starting to see this on scans. A large review looked at 71 studies with nearly 100,000 people. Those who watched more short videos like Reels and TikTok had weaker attention and weaker self-control. The people who used social media compulsively had the worst results, which is why I want you to take this kind of addiction seriously.

It shows up in young people too. A study in JAMA followed more than 6,500 American children from age 9 to 13. The kids whose social media use climbed to three or more hours a day scored up to 4 to 5 points lower on reading and memory tests.

I call this negative neuroplasticity. When you stop challenging your brain, it still changes, but in the wrong direction.

The good news: your brain bounces back

In one study, 467 adults blocked the internet on their phones for two weeks. They could still call and text. Their focus improved as if they were ten years younger.

What did they do with the extra time? They saw people face to face, exercised more, and went outside. Phone down, brain up.

The problem with the chair

There is one more issue with scrolling, and it is the sitting.

When your muscles work, they release a protein called BDNF that acts like fertilizer for brain cells. Scrolling keeps you still.

Researchers at Johns Hopkins followed about 600 adults for 20 years. Each extra hour of TV a day was linked to about half a percent less gray matter, roughly a year of brain aging for every daily hour of screen time. That study looked at TV, not Instagram, but both involve sitting and watching.

Not all screen time is equal. Reading and brain games that make you think are linked to a sharper mind, and older adults who use the internet in moderation have about half the risk of dementia. The screen is not the enemy. Endless, mindless scrolling is.

Four steps to take back control

1. Know your number

Open the screen time setting on your phone and look at your daily average. Most people are surprised. Then pick a realistic daily limit for social media and hold to it.

2. Put a lock on the door

Do not rely on willpower. These apps are built to be addictive. Use your phone’s app limits or a blocker during work hours, family dinners, and the hour before bed. Once a day, put your phone out of reach for two or three hours if you can.

3. Follow the 15-minute rule

Never scroll randomly for more than 15 to 20 minutes at a stretch. Set a timer. When it goes off, stand up, stretch, and walk around.

4. Trade scrolling for growing

Use your screen to learn, not to drift. Practice a language, take an online course, read the news, listen to an audiobook on a walk, or call a friend instead of watching strangers. Every hour you move from scrolling to learning is an hour building new trails in your brain.

Same hours, two different brains

Picture two identical twins, each with six free hours a day for a year.

The first spends those hours scrolling. The second reads books, takes a Spanish class, walks in the park, and goes to a dance class with friends.

No one has run this exact experiment, and it would be hard to do. But after 35 years of studying neuroplasticity, I have no doubt how it would end. The first twin’s networks for focus and memory would weaken from lack of use. The second twin’s brain would build new connections and grow stronger.

Your phone is a wonderful tool. Use it well, and do not let it use you. Your brain is changing every day. The only question is which way.

Frequently asked questions

 
Dr. Majid Fotuhi is a Harvard- and Johns Hopkins-trained neurologist, bestselling author of The Invincible Brain (USA TODAY Bestseller), and one of the world’s leading experts on brain health and cognitive performance. He has spent more than three decades studying the brain’s capacity for growth and repair. To discover your brain health score and receive a personalized 10-page report, take the free Invincible Brain Assessment at invincible.drfotuhi.com.

📺 Watch the full video on Dr. Fotuhi’s YouTube Channel.

Your Brain On Social Media: Why You Can’t Focus Anymore

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References

1. Maguire EA, et al. Navigation-related structural change in the hippocampi of taxi drivers. PNAS. 2000;97(8):4398-4403.
2. Draganski B, et al. Neuroplasticity: changes in grey matter induced by training. Nature. 2004;427:311-312.
3. Mårtensson J, et al. Growth of language-related brain areas after foreign language learning. NeuroImage. 2012;63(1):240-244.
4. Erickson KI, et al. Exercise training increases size of hippocampus and improves memory. PNAS. 2011;108(7):3017-3022.
5. Nguyen L, et al. Feeds, feelings, and focus: a systematic review and meta-analysis of short-form video use. Psychological Bulletin. 2025;151(9):1125-1146.
6. Nagata JM, et al. Social media use trajectories and cognitive performance in adolescents. JAMA. 2025.
7. Castelo N, et al. Blocking mobile internet on smartphones improves sustained attention, mental health, and subjective well-being. PNAS Nexus. 2025;4(2):pgaf017.
8. Common Sense Media. The Common Sense Census: Media Use by Tweens and Teens, 2021.
9. Dougherty RJ, et al. Long-term television viewing patterns and gray matter brain volume in midlife. Brain Imaging and Behavior. 2022;16(2):637-644.
10. Cho G, Betensky RA, Chang VW. Internet usage and the prospective risk of dementia. Journal of the American Geriatrics Society. 2023.

The food you eat has a real effect on how well your brain works, both today and years from now.

One of the most hopeful things I have learned in 35 years of research and clinical work, mostly at Harvard and Hopkins, is that your brain is not fixed. It can grow, and it can get stronger. One of the easiest ways to help it grow is sitting right on your plate.

Think of your brain as a garden. Every day, what you eat either waters that garden or fills it with weeds.

Here are the ten foods I would put at the top of the list, counting down to the one with the strongest evidence behind it. These are foods I eat myself.

10. Eggs

The yolk is one of the best sources of choline. Your body uses choline to make acetylcholine, a chemical messenger essential for memory and learning.

Eggs also give you vitamin B12, which your brain and your nerves depend on, and lutein, an antioxidant that collects in the brain.

They are quick, cheap, and easy to cook. Try them with a handful of spinach, and by number one you will see why that pairing is so good.

9. Whole grains

Oats, quinoa, brown rice, whole wheat.

Your brain cells are the most active cells in your body. The brain is about 2 percent of your body weight but uses about 20 percent of your energy, roughly ten times its share.

Whole grains give it a steady supply of fuel, like a slow-burning log in a fireplace. White bread, sugary cereal, cookies, and donuts are more like burning paper: a quick flash, then nothing.

Sugary food grows weeds in your brain. It raises inflammation in your blood vessels and your brain, contributes to insulin resistance and diabetes, and over time can raise your risk of brain shrinkage and Alzheimer’s.

A bowl of oatmeal with berries and walnuts is a good way to start the day. It is what I eat most mornings.

8. Beans and legumes

Lentils, chickpeas, black beans.

They are full of fiber and folate, and they release their energy slowly, so they keep your blood sugar steady.

Beans also feed the good bacteria in your gut. In return, those bacteria make short-chain fatty acids, molecules tied to better immunity and better brain function.

I eat black beans at least once a week. Add chickpeas to a salad, have black beans as a side, or cook a big pot of lentil soup on Sunday to eat all week.

7. Coffee and green tea

Good news for caffeine lovers. In moderation, coffee and tea sharpen focus and attention.

Both contain polyphenols that may protect brain cells over time. Green tea also has L-theanine, which gives you a calm, focused alertness. Moderate coffee and tea have been linked to lower dementia risk.

Enjoy your cup in the morning, and skip it in the late afternoon so it does not steal your sleep. In the evening, a cup of chamomile or valerian root tea can help you sleep, and good sleep is one of the most powerful brain boosters there is.

6. Dark chocolate and cocoa

Cocoa contains flavanols that improve blood flow to the brain. In one study, older adults whose diets were low in these flavanols improved their memory after taking a cocoa flavanol supplement.

Choose dark chocolate that is at least 70 percent cocoa, and keep it to a square or two. This is a treat, not a meal.

We are halfway. Ask yourself how many of these are already in your week. If it is only one or two, that is good news, because you have room to grow, and the most powerful foods are still ahead.

5. Nuts, especially walnuts

A walnut even looks like a little brain. Nature has a sense of humor.

Walnuts are rich in vitamin E, plant-based omega-3s, and antioxidants. A small handful a day is enough. Keep a jar of nuts on your desk instead of chips.

4. Extra virgin olive oil

This is the heart of the Mediterranean diet, which is tied to good brain health.

It is full of healthy fats and polyphenols that protect your blood vessels. Your brain is fed by blood vessels, so healthy pipes mean a healthy brain.

A Harvard study that followed more than 90,000 Americans found that people who had more than half a tablespoon of olive oil a day had a 28 percent lower risk of dying from dementia.

Use olive oil instead of butter, and drizzle it on your vegetables and salads.

3. Fatty fish

Salmon, sardines, mackerel, trout.

Much of your brain is made of fat. One of the most important is DHA, an omega-3 that builds the walls of your brain cells so they can communicate with each other.

My own research found that people with higher blood levels of omega-3 fatty acids are less likely to develop Alzheimer’s.

While we are on fats, avoid the trans fats in French fries, fried chicken, donuts, cookies, crackers, and frozen pizza. They raise inflammation in your body and brain, and they grow more weeds in your garden.

Try to eat fish twice a week. Canned salmon or sardines on whole-grain toast makes a quick, cheap lunch.

2. Berries

Blueberries, strawberries, blackberries.

Their color comes from flavonoids that calm inflammation and protect the hippocampus, your memory center.

In the large Nurses’ Health Study, women who ate the most berries delayed their memory decline by up to two and a half years.

Keep a bag of frozen berries in the freezer. They are just as healthy, and they never go bad.

1. Leafy greens

My number one, and the one with some of the strongest evidence: spinach, kale, collard greens, arugula.

These greens are packed with folate, vitamin K, and lutein, which protect your blood vessels and your brain cells.

In a study from Rush University, older adults who ate about one serving of leafy greens a day had memory and thinking skills like people about eleven years younger.

Eleven years, from a salad a day. That is a good deal. Toss a handful of spinach into your eggs, your soup, or your smoothie, and you will not even taste it.

The secret that matters more than any food

There is no single magic food. A blueberry cannot save your brain by itself. What matters is the pattern, what you eat most days over many years.

And food is one leg of the table. Your brain does best when you combine good food with exercise, sleep, stress reduction, and brain training, the five pillars of brain health. The more legs the table has, the steadier it stands.

So here is my challenge for you this week. Pick one food from this list and add it to your meals. Just one. Next week, add another. Small steps, repeated over time, create big changes.

Your brain is not destined to decline. Every meal is a chance to give it what it needs to grow.

Frequently asked questions

References

1. Morris MC, et al. Nutrients and bioactives in green leafy vegetables and cognitive decline. Neurology, 2018.
2. Devore EE, et al. Dietary intakes of berries and flavonoids in relation to cognitive decline. Annals of Neurology, 2012.
3. Morris MC, et al. Association of seafood consumption, brain mercury level, and APOE ε4 status with brain neuropathology in older adults. JAMA, 2016.
4. Tessier AJ, et al. Consumption of olive oil and diet quality and risk of dementia-related death. JAMA Network Open, 2024.
5. Brickman AM, et al. Dietary flavanols restore hippocampal-dependent memory in older adults with lower diet quality and lower habitual flavanol consumption. PNAS, 2023.
6. Barnes LL, et al. Trial of the MIND diet for prevention of cognitive decline in older persons. New England Journal of Medicine, 2023.

Your gut and your brain talk to each other all day, every day.

When you feel nervous, your stomach gets butterflies. That is your brain talking to your gut. It also works the other way. What happens in your gut can change your mood, your memory, and even the size of your brain.

I am a neurologist and an adjunct professor of neuroscience at Johns Hopkins. Let me show you how your gut affects your brain, and give you some simple steps to make both stronger.

The two-way highway

Think of your gut as a long tube. Food goes in, your body takes what it needs, and the rest goes out.

The inside of that tube is lined with a thin wall of cells. These cells hold hands very tightly. They let nutrients pass into your blood and keep everything else out.

Around the tube, there are many blood vessels carrying nutrients to your body and your brain. There is also a rich network of nerves. These nerves send messages from your gut up to your brain, and your brain sends messages back down, telling your gut how fast to move and what to release.

Scientists call this two-way highway the gut-brain axis.

The trillions living inside you

Your gut is home to trillions of bacteria, fungi, and viruses. Together they are called your microbiota.

Some are good for you, some are not. When you are healthy, they live in balance.

The good bacteria love one thing above all: fiber. When they eat fiber, they make molecules called short-chain fatty acids.

These molecules are a gift from your bacteria back to you. They keep your gut wall strong. They calm inflammation in your gut. They help control blood sugar. And they help the brain, supporting better memory and overall brain function.

What goes wrong with age

Here is the catch. As we age, we lose variety in our gut bacteria. We make fewer of these helpful molecules, and inflammation goes up. Scientists even have a name for it: inflammaging.

Sometimes the bad bacteria start to outnumber the good ones. Beyond aging, the usual causes are long courses of antibiotics, chemotherapy, stress, obesity, a poor diet, and air pollution.

When this happens, the gut wall can become inflamed. The cells stop holding hands so tightly, and some bacteria and toxins slip into the blood. People often call this a leaky gut.

To be clear, leaky gut syndrome is not an official diagnosis. But a gut wall that leaks more than it should can trigger inflammation in the gut.

How gut trouble reaches the brain

That inflammation does not always stay in the gut. It can travel, and it can reach other organs, including your brain.

Gut toxins floating in the blood can damage the protective lining of blood vessels in the brain and reach deep inside it.

So a leaky gut can be harmful for your brain. It can play a part in depression, anxiety, brain fog, memory loss, and over the long run even brain shrinkage and Alzheimer’s disease.

What the research shows

Let me share two studies on the link between diet and brain health.

In the Framingham Heart Study, researchers looked at about 1,900 adults. People who ate a poor diet, rich in sugar, fried food, and trans fats, the so-called inflammatory foods, had smaller brains.

In a study of 581 people who donated their brains for research, scientists found that those who had followed a Mediterranean diet closely had less Alzheimer’s damage. Their brains looked about 18 years younger than the brains of people who did not eat that way.

The message is simple. What you feed your gut can affect your brain, for better or worse.

So should you take probiotics?

Probiotics are the live bacteria themselves. Walk into any pharmacy, and you will see shelves of probiotic pills.

Here is the truth. Scientists still do not know which strains you need, or how much. Most GI medical organizations do not recommend any specific probiotic pill or brand for otherwise healthy people with no gut issues.

So what should you do instead? Use food to feed the good bacteria you already have, and food that brings in more healthy live bacteria. Here is the plan.

Your four-step plan

First, feed your good bacteria with high-fiber foods. Beans, lentils, and chickpeas. Oats and whole grains. Onions, garlic, leeks, and asparagus. Apples, berries, and bananas. Nuts, flaxseed, and chia seeds.

Most adults get only about half the fiber they need. Add one of these foods to every meal, and go slowly so your gut can adjust.

Second, get your probiotics from food, not pills. Plain yogurt with live cultures. Kefir. Sauerkraut and kimchi, the kind you find in the refrigerator. Miso. Start with one small serving a day.

Third, choose good fats. Salmon, sardines, olive oil, avocado, and walnuts are high in omega-3 fatty acids and calm inflammation. Higher omega-3 levels have also been linked to a bigger hippocampus, your memory center, and a lower risk of Alzheimer’s disease.

Fourth, cut back on what hurts your gut and can shrink your brain. Fried foods. Fast food. Sweets and pastries. White bread and sugary cereals. They cause blood sugar spikes and inflammation, and they harm both your gut and your brain.

The bottom line

Your gut and your brain are partners. When your gut is healthy, your brain does better.

You do not need expensive pills. Feed your good bacteria with the high-fiber foods they love, add a little fermented food, choose good fats, and skip the junk.

These changes lower inflammation and raise your levels of short-chain fatty acids, those healing molecules for every organ in your body, including your brain.

Make small changes every day. Over time, your gut becomes like a healthy garden, and your brain is better for it. You really can use the gut-brain connection to keep both strong for years to come.

Frequently asked questions

📺 Watch the full video on Dr. Fotuhi’s YouTube Channel.

What Happens to Your Brain When You Actually Fix Your Gut

Keep up with Dr. Fotuhi on LinkedIn & Instagram.