Sugar and ADHD

child with lollipop - sugar and ADHDDoes sugar cause ADHD symptoms? 

While many parents suspect that sugar plays a role in their children’s behavioral patterns, short-term studies conducted in the 1980’s and 1990’s were not able to show a connection between sugar and hyperactivity or attention problems.




These studies compared the effects of sugar (sucrose) to artificial sweeteners (aspartame/Nutrasweet® or saccharin/Sweet ’n Low®) on children over a period of days to a few weeks.  However, the problem is this:  researchers did not remove other high glycemic index and refined carbohydrates from children’s diets, only sugar.  There are many foods which rapidly break down into simple sugars in the body, such as flour, corn starch, white potato, and fruit juice.  Therefore there was still a significant amount of sugar in the diets of all of the children in these studies:

“In addition to the drink, each child was served either (1) one slice of white toasted bread spread with 1½pats of butter on days that the sugar sweetened drink was served on (2) two slices of white toasted bread spread with 3 pats of butter on days that either placebo drink was served. The amount of carbohydrate and fat contained in the toast and butter, in addition to the drink, provided an approximately equal amount of calories each testing day. All children were offered an identical lunch of French fried potatoes prior to the last testing session.”  [Wender 1991]

Can you believe it?  A breakfast of white bread and a lunch of French fries?  This diet consisted almost entirely of high glycemic index refined carbohydrate and fat, and almost no protein.  So, all we really know is that removing sugar from a junky diet and replacing it with artificial sweeteners does not make ADHD symptoms better.  We do not know if adding sugar to a healthy diet can cause ADHD symptoms, or whether removing all refined carbohydrates from the diet could reduce ADHD symptoms.  In 1995, a comprehensive analysis of all sugar studies to date concluded that there was no evidence that sugar caused ADHD (although the authors acknowledged there weren’t enough studies to be certain).  This influential JAMA paper seemed to close the case, because no studies of sugar and ADHD have been conducted since.

This is your brain on sugar

In a Yale study of healthy children without ADHD, blood levels of glucose and a variety of hormones and neurotransmitters were measured before and after a sugary drink (decaffeinated cola sweetened with glucose; equivalent to two 12-oz cans of Coca-Cola).  These children were compared to a control group of children drinking a diet cola.  In the sweet cola group, the expected spike and drop in blood sugar occurred:  blood sugar rose from a fasting level of 83, to a peak of 135 after the cola, then to a valley of 61 about 4 hours after drinking the cola (values are in mg/dl). When blood sugar bottomed out, blood levels of epinephrine (aka adrenaline, our fight or flight hormone) skyrocketed to 5 times higher than they had been before the cola. When this occurred, the children felt panicky—shaky and weak with a pounding heart. These are the symptoms we typically associate with “hypoglycemia”, but they are actually due to the surge of fight or flight hormone produced by the body in reaction to falling blood sugar, not due to the low blood sugar itself. For more information, including a graph of sugar and adrenaline levels, please see my Psychology Today post Stabilize Your Mood With Food.

These same researchers also studied the electrical activity of the brains of children as their blood sugar dropped.  They found that problems with brain activity could be seen as soon as the blood sugar dropped to below 75 mg/dl, getting worse as it fell even lower.

Sleep, Sugar and ADHD

An interesting Australian study [Blunden 2011] examined the diets and sleep patterns of children with ADHD who were not taking medications.  Children with high-sugar diets were more likely to have disrupted sleep, most commonly breathing problems and night sweats.  Association does not equal causation, but given what we know about sugar and panic symptoms, this connection would make sense.

There’s something about the Western Diet 

A large epidemiological study out of Australia (where would we be without our forward-thinking mates from down-under?) found that teenagers who reported eating a “Western” diet were more than twice as likely to have ADHD than teens who reported eating a “Healthy” diet.

WESTERN                                                            HEALTHY

High total fat                                                      Low total fat

High saturated fat                                             Low saturated fat

High refined sugars/grains                              Low refined sugars

High sodium                                                       Lower sodium

Low omega-3                                                      High omega-3

Low fiber                                                              High fiber

Low folate                                                            High folate

                 FOODS EATEN (in order of frequency)

Take-out foods                                                  Vegetables

Sweets                                                                 Fruits

Refined grains                                                   Legumes

Red meat                                                            Whole grains

Processed meat                                                 Fish

French fries/potato chips                                 Soups

Soft drinks                                                         Meat dishes

Cakes/cookies                                                   Mineral water

White potato                                                      Low-fat dairy

Sauces/dressings                                              Eggs

Full-fat dairy                                                      Juices

Poultry                                                                Nuts


Fish (battered/fried)

Added sugar

This was an observational study and cannot prove cause and effect. There is no way to know whether the Western diet may make ADHD more likely or whether ADHD makes it more likely that a teen will gravitate towards the Western diet (i.e. impulsive teens may make poorer dietary choices).   We have no way of knowing which aspects of the Western diet may be causing trouble here—fat? Sugar?  Refined grains? Sodium?  Or is it the lack of something—low fiber?  Low omega-3’s?  No one food group jumped out as specifically related to ADHD risk; statistically, it was the overall dietary pattern that seemed to be the problem.  However, in other fields of medicine, the trend is pointing away from fat and meat and towards refined carbs and lopsided omega-3/omega-6 ratios.

Does chronic sugar consumption eventually lead to ADHD?

A group of scientists at the University of Colorado thinks that eating sugar on a regular basis may cause long-term problems for the brain that can’t be corrected simply by removing sugar from the diet in short-term studies [Johnson 2011]. Theoretically it is possible that the chronic use of sugar could cause changes in brain chemistry that may eventually lead to ADHD, but there have not yet been any studies exploring this question.  Here is their reasoning:

  1. Sugar is a powerful trigger for dopamine release in the brain (dopamine is one of the brain chemicals thought to be involved in ADHD)  Eating sugar floods brain cells with dopamine, which feels good, because dopamine is our pleasure/reward neurotransmitter. Channeling Homer Simpson:  “Mmmmmm…Donut…”
  2. The brain tries to bring dopamine activity back to normal by reducing the number of dopamine receptors, so it will then take even more sugar to produce the same effect (tolerance). “Mmmm…two donuts…”
  3. If a person keeps eating sugar, there may be times when brain cells run low on dopamine from being stimulated so frequently.  Low dopamine activity is one of the possible causes of ADHD symptoms.  This vicious cycle may also lead to binge eating and sugar addiction.  “Donut…donut…donut…donut…Marge, we’re out of donuts!”

ADHD and Obesity

Children with ADHD are about twice as likely to be overweight or obese and vice versa. Is there something about ADHD that causes overeating or obesity?  Is there something about obesity that causes ADHD?  Or does it go both ways?  In a large German epidemiological study:

“…children with ADHD more often endorsed ‘‘lost control over eating’’ and ‘‘food dominates life’’ than their peers without ADHD…” (regardless of body weight).  [Erhart 2012]

There is a strong connection between the consumption of high glycemic index and refined carbohydrates and the obesity epidemic.  However, because we do not yet have any studies of refined carbohydrate and ADHD, we do not yet know if refined carbohydrate may be one of the bridges connecting ADHD and obesity.

What about low-carb diets for ADHD?

Unfortunately, there have not yet been any studies of low-carbohydrate diets in people with ADHD.  However, one study of the ketogenic diet (a special low-carbohydrate diet) on children’s behavior found small but significant improvements in attention and social problems compared to children eating a regular diet. These were children with seizure disorders, not ADHD.  [The differences in behavior were not due to the fact that these children had many fewer seizures than the children eating a regular diet.]

The bottom line about sugar 

Studies of sugar itself, compared to artificial sweeteners, have not found a connection between sugar and ADHD.  However, wondering whether sugar per se is a culprit in ADHD may not be the right question to ask.  Since sugar and other refined and high glycemic index carbohydrates behave the same way in the body, it would make more sense to ask whether refined carbs, as a food group, increase risk for ADHD, and as of today there are no studies exploring this possibility.

However, here’s what we do know:

  • Refined carbs such as sugar put the brain and body on a hormonal roller coaster that can cause panic symptoms and brain dysfunction.
  • Diets high in refined carbs increase risk for insulin resistance, high insulin levels, diabetes, heart disease, and obesity.
  • Insulin can reduce dopamine levels in the brain.

It is hard to know what all of this means for people with ADHD.  However, it would make sense for everyone, including those with ADHD, to stay off of this hormonal roller coaster as much as possible.

It all starts with breakfast

Refined carbohydrates include sugar, honey, all kinds of flour, maple syrup, corn syrup and even fruit juice (see a list of refined carbs)  In fact, the typical “healthy American breakfast” tends to be the meal that is highest in refined carbs and lowest in protein—waffles, muffins, toast, instant oatmeal, cereals, bagels, orange juice, etc.  Making changes to breakfast is the most important place to start for families, but most children eat far too much sugar all day long.  Contrary to popular belief, fruit juice, chocolate milk, granola bars, sweetened cereals, home-made desserts, whole-grain muffins, and fruit juice-based candies are not healthy foods for children. All of these foods are very high in sugars, which are strongly associated with high insulin levels and inflammation throughout the body.  This is not the kind of inflammation you can see with the naked eye; it can only be detected by special blood tests in research labs.  Over time, this microscopic inflammation can be very damaging to all of the organs of the body, including the brain.

For more information about carbohydrates and health, check out my carbohydrates page.  Learn how to stabilize blood sugar on my carb sensitivity diets page.

For further reading, I suggest my post, “Attention! Is Your Diet Causing ADHD?” and “Food Sensitivities and ADHD.”

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Blunden SL et al.  Diet and sleep in children with attention deficit hyperactivity disorder:  preliminary data in Australian children.  J Child Health Care 2011; 15(1):14-24.

Erhart M et al.  Examining the relationship between attention-deficit/hyperactivity disorder and overweight in children and adolescents.  Eur Child Adolesc Psychiatry 2012; 21:39–49.

Howard AL et al.  ADHD is associated with a “Western” dietary pattern in adolescents.  J Attention Disorders 2011; 15(5):403-411. 

Johnson RJ et al.  Attention-deficient/hyperactivity disorder:  is it time to reappraise the role of sugar consumption?  Postgrad Med 2011; 123(5); 39-49. 

Jones TW et al.  Enhanced adrenomedullary response and increased susceptibility to neuroglycopenia:  Mechanisms underlying the adverse effects of sugar ingestion in healthy children. J Pediatr 1995;126(2):171-7.

Palmiter RD.  Is dopamine a physiologically relevant mediator of feeding behavior?  Trends in Neurosciences 2007; 30 (8): 375-381.

Pulsifer MB et al.  Effects of ketogenic diet on development and behavior:  preliminary report of a prospective study.  Developmental Medicine & Child Neurology 2001; 43: 301–306.

Wender EH and Solanto MVEffects of Sugar on Aggressive and Inattentive Behavior in Children With Attention Deficit Disorder With Hyperactivity and Normal Children. Pediatrics 1991;88: 960-966.

Wolraich ML et al. The effect of sugar on behavior or cognition in children:  a meta-analysis. JAMA 1995;274:1617-1621.

Please note that after 30 days, Dr. Ede may not personally respond to comments, however comments shall remain open to encourage community discussion.
  • Someone, Somewhere

    Very interesting, Dr. Ede. Thanks for sharing all of this.

    In discussions of the healthfulness of sugar, one variable seems to almost always be missing–and from my perspective, this is a key variable: timing.

    If I drink fruit juice on an empty stomach–which I no longer do–I feel hyper and anxious, then depressed. If I drink fruit juice, however, right after eating a large meal of meat–which I do 1-3 times per day–I feel great: no feeling of “spiking” or “crashing.” I’ve read that protein and fat significantly slow digestion, thereby slowing the absorption of sugar and modulating blood sugar levels.

    This, of course, begs the question: Why drink fruit juice at all? The answer: Because I feel better when I do so, and I’m inclined to believe that humans have evolved to do so. When I eat meat without any additional source of antioxidants (ideally, fruit juice, but whole fruit, acidic vegetables, spices, sauces, and even vinegar work), I feel bad: anxious and depressed.

    Furthermore, I enjoy eating whole fruit throughout the day, on an empty stomach, with no adverse psychological effects. I’ve read that the fiber therein slows digestion and therefore modulates blood sugar levels.

    I suspect that juice is more attractive to me while consuming meat because the antioxidants are more concentrated, and are more desired by the body to neutralize the oxidation of the meat (I carefully minimize oxidation and maximize antioxidant creation by the methods of food preparation I use, but it seems that my body still wants extra antioxidants to balance it out).

    One may argue, based on limited science, that the nutritional value of antioxidants found outside of meat hasn’t been proven, but I value the data my senses give me as much as published research. Plus, humans are instinctively drawn to fruit, which is prized, consumed, and found in probably every well-populated region of the world, and is available perennially in the much-loved tropics.

    Plus, squeezing a fruit like an orange requires zero tools and could have been done by our earliest ancestors, so it is a plausible hypothesis that we are adapted to fruit juice as well (alternatively, perhaps antioxidants were more densely concentrated in ancient, wild, uncultivated fruit, and therefore didn’t need to be concentrated via juicing).

    That said, I agree with your criticisms of the vast majority of carbohydrates that Westerners ingest: grains and other refined so-called “foods.”


    • Hi SS

      I agree that fruits are the healthiest sources of sugars available, for those who can safely eat carbohydrate, and yes, most of our ancestors ate fruit for millions of years. We each vary in our ability to metabolize high glycemic index foods, and my hunch about this is that once our carbohydrate processing system is “broken” by some aspect(s) of modern lifestyle, then all high glycemic index carbs, including fruit juices, become metabolically risky. Had we all been raised on a healthy whole foods diet, my belief is that we would all be able to handle fruit, and even fruit juices, without fear.

      As for fruit juices being naturally available to ancestors, I can only speculate, but I imagine that some fruits could be easily juiced (oranges) whereas others could not (apples). In any case, having daily access to high quantities of fiber-free juice was probably not the norm?

      I also agree that protein, fat and fiber can slow the digestion of carbohydrate and lessen blood sugar and insulin spiking. However, I wonder if you have ever tested your own blood sugar after drinking fruit juice with meat compared to meat alone? I am also curious to know if you have ever tried removing carbs from your diet for a week or more, to see if your body responds differently to meat and whether your interest in fruit juices changes? The reason I ask is that the bad feelings you experience when you stop drinking juice may be a temporary withdrawal syndrome, which can last up to a few days.

      • Someone, Somewhere

        Hi Dr. Ede,

        Good point about the unjuicability of most fruits without special equipment. I suppose our ancestors probably did not juice much. I was looking for evolutionary hypotheses to explain the instincts that draw me to juice after eating meat, while they draw me to whole fruit at other times. A more viable hypothesis, I suppose, would be that antioxidants were more densely concentrated in ancient, wild, uncultivated fruit. I believe I’ve read a study showing that this is the case, somewhere, which makes sense given that modern farmers strive to cultivate fruits that are bigger and bigger and bigger.

        I have not tested my blood sugar after drinking fruit juice with meat compared to meat alone. I don’t know why I would want to. The only reason I would be motivated to test my blood sugar would be if I were concerned about my health, and since I am not, I have no motivation. Besides, I trust my body and my instincts more than any isolated number. For example, I let my body tell me how to regulate my iron and omega-3 levels by seeing when I feel like eating beef or wild seafood, rather than getting blood tests and popping pills. I’ve been feeling way healthier since I made this shift from letting doctors determine my decisions to letting my instincts guide the way, even though I do use science to try to present my body with the kinds of options it might have had in the Environment of Evolutionary Adaptedness (EEA). I hope I don’t sound defensive here. I’m just trying to explain why I personally wouldn’t find the results of such a test relevant to my food choices.

        To answer your other question, I have never tried removing carbs from my diet for a week or more, to see if my body responds differently to meat and whether my interest in fruit juices changes. The idea of doing so sounds so uncomfortable, that I simply have no interest in doing so. Plus, I feel healthier than I’ve ever felt on the diet I’m currently on—and it seems to be about as adaptive as I can make it—so I’m not really motivated to conduct an experiment that I know would make me feel terrible. To be clear, I don’t think it’s sugar that I’m addicted to. The sugar is not what compels me to eat fruit and drink fruit juice: more than anything, I think it’s the antioxidants. It’s the sourness that I crave. I just like/need the sugar to buffer the acid. If no fruit were available, I’d sip on vinegar alongside meat, if doing so wound’t burn my alimentary canal.

        I’m still curious what you think about my theory that it’s antioxidants that drive my desire to drink fruit juice alongside meat, to balance the oxidation. I believe you’ve written, elsewhere on your site, that the antioxidant capacity of fruit is overrated, and the antioxidant capacity of meat and endogenous substances in the human body are underrated. Could it be, though, that to maximize health, we are still instinctively wired to ingest as many antioxidants as we possibly can, alongside meat (which, presumably, oxidizes after ingestion as much as before)?

        Putting fruit and fruit juice aside for a moment, consider the history of cooking: The vast majority of cooking methods known to humans seem to be designed to minimize oxidation (in some cases) and maximize antioxidants (in even more cases). Serving food that is minimally heated—especially food rich in easily oxidized omega-3 fatty acids, such as raw sushi, steamed fish, and medium-rare grass-fed beef—minimizes oxidation. And sauces, marinades, herbs, spices, and browning a la the Maillard reaction all serve the purpose of increasing antioxidants (as well as killing bacteria). Personally, I avoid all sauces, marinades, herbs, and spices, and cook meat as closely as I can to how our ancestors might have—completely unadulterated—to avoid the deleterious “anti-nutrients” found in non-fruit plant parts, but I still enjoy a steak most when it is well-seared on the outside and medium-rare on the inside (blind taste tests show that this preference is near-universal). Most people mix fruit or other plants into sauces, marinades, chutneys, etc. I keep is simple, and eat or drink it alongside my meat, as our ancestors might have, but regardless, it seems that everyone or nearly everyone enjoys a significant dose of antioxidants alongside their meat. Is this not compelling—or at least suggestive—evidence that the antioxidant capacity of fruit has significant value both in human evolution and for modern humans, even if we don’t (yet) have double-blind placebo-controlled trials or petri dish studies to prove it?

        Finally, as for your hunch that “once our carbohydrate processing system is ‘broken’ by some aspect(s) of modern lifestyle, then all high glycemic index carbs, including fruit juices, become metabolically risky”: I agree. However, the body is highly adaptable—is it not likely that this “brokenness” is, in many cases, reversible? Personally, the only things that go into my body, these days, are meat, fruit, water, and sea salt, with rare exceptions. But I grew up eating a Standard American Diet (SAD). And yet I feel healthier than ever eating fruit, and my mood has never been more satisfying and stable. Perhaps you are simply recognizing that extremely few people have the discipline to eat a diet as simple as mine or have given their bodies time to recover from the SAD, and you are therefore recommending limiting fruit because this is what makes sense for the masses?

        • Hi SS

          No worries, I didn’t mean to imply that you should test your blood sugar, I was only asking out of curiosity.

          I am not convinced of the benefits of antioxidants, and will eventually be writing more about this very complicated topic. We have our own internal antioxidants. However, I also would never disagree with any individual’s personal experiences, because we are each different.

          I personally am not able to tolerate carbohydrate without a variety of negative consequences, and no matter how many times I try to reintroduce them, it never changes. I certainly wish it would! However I do not know if others may be able to overcome this problem once it develops, I only know that I can’t, so again, I wouldn’t hazard a guess about the general population.

          • Someone, Somewhere

            Thanks, Dr. Ede.

            In retrospect, I could see how my comment about my “shift from letting doctors determine my decisions” could be read as a slight at you. To be clear, I wasn’t even thinking of you when I wrote that. I see you as the best kind of doctor, one who expresses curiosity, embraces others’ personal experiences, and discusses science with an open mind. As I said before, I wish you had been at UHS when I was a student there, and that I had consulted with you back then—could have saved me from a number of health problems.

            I find it interesting that two people with relatively similar diets—almost entirely meat-based, and almost no plants—would react so differently to fruits. I’m curious if you have an explanation or speculation regarding these individual differences.

            Regardless, I am very much looking forward to reading what you have to write about antioxidants. I hope and expect you’ll go beyond the argument that people (the Inuit and their visitors, for example) have subsisted on a diet of virtually 100% meat, and that this therefore proves that plant-based antioxidants are superfluous to human health. I imagine you would agree that the possibility of subsistence, and even healthful biochemical markers, does not prove optimum health.

            Perhaps you could make a compelling argument for why some people—like myself—would crave plant-based antioxidants alongside meat on a regular basis, while people like yourself respond poorly thereto. That, to me, would be much more interesting than a one-size-fits-all model that simply says “plant-based antioxidants are good,” “plant-based antioxidants are superfluous,” or “plant-based antioxidants are bad.” A tall order, I realize, but I suppose it can’t hurt to ask 🙂

          • Hi SS

            I didn’t feel slighted in the least:) I just wanted to make sure that we weren’t misunderstanding one another. I wish I understood what makes us each so different when it comes to tolerating the natural chemicals that exist in foods, but yes, I have a very healthy respect for individual variation. I see it every day in my psychopharm practice, where it never ceases to amaze me how differently people can respond to the same medication. I love a challenge, and your antioxidant questions have laid down the gauntlet! I will do the best I can…but it will take a while!

          • Someone, Somewhere

            Makes sense, Dr. Ede. I look forward to your response to my challenge 🙂

  • Annemieke Van Bochove-van Oost

    We have tried to give our 9year old boy with ADD low carb food. Eg proteinbread, eggs, many vegetables, but still fruit and other with complex carbs.
    We do see that he isn’t hyper anymore, more equal all day long. Especially at night, normally he was extremely active and loud, and yet he’s quiet, relaxed. And falls much easier asleep.
    We do make exceptions, eg an easteregg or potatoes with friends, and after eating that he is again active, hyper and after 1-2 hours extremely tired…
    We would like to know more about it, because we don’t want to keep away important building stones for a growing boy, but do see mportant changes. He also sees / feels it himself clearly. Could you give us tipps or ideas about this theme, so that we could try out a normal diet, thats good for his age?

    We are curious! Cannot find much in this theme, surely not in Dutch or German (we’re dutchied living in switzerland)