Why Does Sugar Give Me a Headache?

Why Does Sugar Give Me a Headache?

Does eating sugar give you a headache?You are not alone.

The sugar headache, otherwise known as the Holiday Headache (because we eat so much sugar on Easter, Halloween, Christmas and other holidays) has a lot in common with a hangover but it strikes any time we overdose on sugar.


While most of us have experienced a sugar headache at some time in their lives it is not well-known in medical circles. It might even surprise you to learn that the exact causes of all headaches are a bit of a mystery. Scientists have discovered that both migraines and cluster headaches change blood flow in the brain,  but exactly how blood flow changes create a headache is unknown. The same is true of the sugar headache.

I view the sugar headache as a toxicity or dehydration event and while it might be an annoyance, it could also be the sign of something more dangerous. Let’s look at dehydration and toxicity and see how they might cause a headache.

Sugar Dehydration

Dehydration is a common way to get a headache and sugar can lead to dehydration. Eating too much sugar pulls water out of your body in two ways.

  • Dilution: When you eat too much sugar, your body has to dilute that sugar to keep it from harming your body. This means that water is pulled from all parts of your body to balance the large amount of sugar in your blood stream. While this water-pulling effect happens all over the body, it is your head that suffers the most.
  • Urination: One of the ways that your body has of getting rid of excess sugar is to dump it in your urine. This is especially true of diabetics, who have to go to the bathroom a lot.


The other way to think about sugar is to consider it a toxic event.

While your body runs on glucose (a simple sugar) it was never meant to have a ton of simple sugars running around in your blood. If you look to nature, you would find that there are almost no foods that contain the high amount of sugar you would find in any soda or piece of cake. If natural foods do contain a high amount of sugar it is often bound up and hard to get to (like in a sugar cane). The only way to get a large amount of sugar into your body is to have that sugar processed before you put it in your mouth.

Processed sugar and processed grains both act like sugar in your body and this is toxic to the very blood cells that carry the sugar throughout the body. (I explain this at length in my book Sugarettes).

Something Worse?

Sugar headaches can also be a warning. If you get sugar headaches often, you might just be diabetic or pre-diabetic. The best way to find out if you are diabetic is to go and see your doctor and have them run some blood tests, but here are the typical symptoms of diabetes:

  • Excessive urination: As I mentioned above, sugar acts like a diuretic and will spill sugar and water into the urine. Having to urinate a lot is often one of the first signs of diabetes.
  • Excessive thirst: Since diabetics are losing a lot of water (see above), they are often thirsty all the time.
  • Excessive hunger: Everyone has periods of time when they are hungry, but diabetics are hungry all the time (with strong cravings for carbohydrates, sweets and sugar). This is one of the strange things about diabetics: They have a lot of sugar in their bodies, but it is not being used by the cells so they are hungry all the time.

Sugar Headache

The reasons why sugar gives you a headache are many and not readily understood, but you don’t have to wait for a reason to stop the pain in your head.

You can stop your sugar headaches and give sugar the boot by trying my 30 Sugar Free Days Program. During the program, you will learn about foods that act like sugar and what you can do about your cravings. Make sure you understand that sugar is doing more harm to your body than just giving you a sugar headache, take this opportunity to learn from your headache that you shouldn’t be putting large amounts of sugar in your mouth and you need to make a change.

About the Author

I'm Dr. Scott Olson ND. I'm a Naturopathic doctor who specializes in diet, health, nutrition, and alternative medicine. I've written numerous books and articles on health, medicine, and alternative medicine I want to help you get healthy! Take a look at my blog and make sure you join in the conversation!

43 Comments on this article. Feel free to join this conversation.

  1. Alba October 19, 2013 at 11:22 am - Reply

    I was told about 4-5 yrs ago to stay away from sugar and starchy substances and that it is causing me to have all sorts of allergies because the immune system is week because of yeast fungus. I stopped eating most sugar and dropped 60 lbs. I still had nauseous episodes with some shaking and bad headache. Did it for about 2 years but relapsed. And I use the word relapse because it is exactly that. Now I have gained all the weight back and seem to not be able to tolerate icecream and chocolate. The cravings are wicked intense and I screw up a lot. like a dumb puppy. Had an icecream two nights in a row and bam.. Nausea, bad head/face ache, stomach ache, heart feels like racing. Doc says Candida is hocus pocus. he did some testing and said all fine. mild allergy to corn too im told and cats and seasonal and feathers. btw..
    how do i get my doc to listen and more testing?

    • Dr. Scott October 20, 2013 at 12:57 pm - Reply

      I’m not sure that there is any way to get your doc to listen. I’m also not a fan of Candida as being a problem. Yes, people can have an overgrowth when they eat a lot of sugar, but I think it is hard to pin all the problems on a yeast. I would say, though, that people on a Candida-free diet feel great (as do most people who decide to stop eating sugars and foods that act like sugars). My advice? Kick all grains and sugars out of your life and see how you feel.

      Best of luck,

      Dr. Scott

    • Heather November 7, 2013 at 4:09 pm - Reply

      You might find Sweet Poison Quit Plan (by David Gillespie) helpful to get you through sugar withdrawal. Has a website & fb page but the book is most helpful.
      Good luck.

  2. Kandice October 11, 2013 at 11:28 am - Reply

    Thanks for the article, I’m going to get tested for diabetes. I have a family history of diabetes and have had frequent headaches for years.

  3. phoenix December 29, 2012 at 3:01 pm - Reply

    I quit smoking and drinking at the same time 12 days ago. ( I drank 4 shots of whiskey every evening for several years) I had a couple peices of chocolate cake left from a Christmas gathering and ate it over a few days and each time it gave a huge headache which it never did before.

  4. Rob June 11, 2012 at 12:57 am - Reply

    This blog is really great. I’ve been reading a lot about sugar today for my first time and am begining to realize what an idiot I am. Sugar seems like a poison to the body tbpo. I get headaches almost everyday because I put a lot of sugar in my tea. I also sweat in my sleep, pee a lot after drinking my tea, and no problems with numbness.

    I’m realizing these are the prestages to diabetes. I am only 29 for christsake.

    SUGAR IS A POSION! It needs to be treated like such. I don’t drink alcohol but I take in too much sugar and it feels like a weaker form of alchol in a way. Alcohol in low amounts. It may have more subtle harmful effects that you don’t notice. Can mess with your hormones over time and cause so many other problems.


    I am not touching it again for the rest of my life after all the blogs I read today.
    Here is a really informative blog on “reversing” diabetes. I did not read it. It was just a blog I read that motivated me to start reading more about sugar.

    I found some of the tips in it VERY helpful.
    Today I realized taking into too many simple sugars can almost become addictive. You wind up with hotflashes, high adrenaline, fatigue, loss of sleep….

    I had no idea it was all from sugar.

  5. cindy francis February 14, 2012 at 11:18 am - Reply

    Headache and having lots of sugar cravings stay hunger all the time plus I’ve gain 15 lbs . My mother is a diabetic . And in the past they told me I’m low sugar and I would be a diabetic I’d I didn’t control my craving and ex. In sleepy and tired all the time….

  6. Susan Blanton February 14, 2012 at 10:26 am - Reply

    One thing that this article failed to mention is Candida and or Aspergillis mold. Sugar feeds fungus and if you have a big Candida or Aspergillis mold infection, sugar can feed these organisms causing brain fog/spaciness and a headache. I always thought I had low blood sugar headaches the day after eating anything sweet, but then was diagnosed with an Aspergillis infection do to some large mold exposures from a water damaged building. Since that time, I have learned that sugar feeds fungus along with many other organisms and causing the headache along with a variety of other symptoms.

    • Dr. Scott February 15, 2012 at 9:06 am - Reply

      Thanks for your comments Susan!

    • Susan Blanton June 11, 2012 at 12:19 pm - Reply

      One other thing I failed to mention is that a doctor in France has shown a relationship between, mold and fugal overgrowth in the body and Cancer. Sugar is known to feed Cancer, it could be that it is actually feeding the fungus which compromises the immune system so that it can no longer fight the Cancer. Also it isn’t just fungus that loves sugar, many other Pathogens love sugar, the Borrelia bacteria found in live disease loves sugar and many parasites love sugar and coexist with Candida.

      • Susan Blanton June 11, 2012 at 12:21 pm - Reply

        Oops, I should have spell checked, I meant fungal not fugal and Lyme not live.

  7. marget January 11, 2012 at 2:09 pm - Reply

    yes ive been getting terrible headaches and im not sure why, my doctor said it was a sinus infection possibly but its not because i took those pills and the head aches/ dizziness, lack of focus, fast heatbeat, an incredibly terrible sweat problem. i am not sure if it could be to much sugar or something worse.

  8. Susan December 26, 2011 at 2:45 pm - Reply

    Over the last six months or so I have changed what I eat and have lost 32 pounds. I stay away from the unhealthy carbs, but still eat things such as hummous, sweet potatoes, whole wheat, etc. In these past six months, on perhaps three or four occasions, I had days where I have eaten “sugar” things – such as birthday cake, holidays cookies, etc. – and the next morning woke up with a pounding headache. Today, the day after Christmas, was one of those days! I found that Benadryl helped – although maybe it was actually the passing of time that did it. Any thoughts or comments?

    • Susan December 26, 2011 at 2:50 pm - Reply

      I should have added that since having changed my eating habits, I have NEVER had a headache except following those handful of days where I have eaten sugary things. Also, shortly after eating the sugary things I feel like I’m “drunk” – dizzy, lack of concentration, and even getty or silly. I have checked my blood sugar at those times (the supplies are in the house since my husband is diabetic) and my blood sugar has always been normal (80-95).

      • Dr. Scott December 27, 2011 at 5:37 am - Reply


        Even though I wrote this post, the reason why people get a headache after eating sugar is a bit of a mystery. Headaches come after drinking alcohol because of dehydration and the toxic effects of the byproducts of alcohol manufacture. These same mechanisms may be at play with the sugar headache. In fact, many of us ferment the sugars that we eat into alcohol that is then absorbed into our systems. Either way, it appears that you are very sensitive to the effects of sugar (from my standpoint, this is a good thing because it will help to steer you in the right direction).

        Hope that helps,


        • Susan Blanton February 14, 2012 at 10:29 am - Reply

          Alcohol not only causes dehydration, but also depletes the B vitamins. Taking B vitamins before you drink often prevents the headache from drinking. If the headache was only due to dehydration, then we should all get headaches when we drink coffee since it also can cause dehydration.

  9. Mary S November 19, 2011 at 7:51 pm - Reply

    Dr. Scott,
    I believe I have a sugar sensitivity as well. Would you be able to give me a sample sugar free diet, as well as other carbohydrates I should avoid (bread? Rice?) or direct me where to find one? Thank you.

    • Dr. Scott November 20, 2011 at 3:20 am - Reply

      Hi Mary,

      I have a free booklet that outlines the sugar free diet, you can get it on this page: 30 Sugar Free Days


  10. Vittorio November 3, 2011 at 10:20 pm - Reply


    Recently, I have noticed that after eating (especially large meals) there is a drop in my mental acuity, along with increased blood flow to my hands (Raynaud’s phenomenon?). The other odd thing is that my mind is most clear when my blood sugar is low (around 75 mg/dL) Fearing that it might be some type of glucose intolerance/diabetes, I bought a blood glucose test kit. After one hour of eating a high-carb meal, it shot up to 176 mg/dL… less than an hour later it went down to 94 mg/dL. Seeing this spike, I decided to map out a meal’s digestion. 505 calories. Started at 92 mg/dL, two hours later 85 mg/dl. This is normal range, but what concerns me is that at 40 minutes after eating, it was up to 164 mg/dL.

    By the way, the meal was 15.75g fat, 63g carbs, and 31.5g protein.

    Are these spikes normal? What does this mean?

    Thank you!

    • Dr. Scott November 6, 2011 at 3:05 am - Reply


      This is all within the normal range. People’s blood sugar typically spikes high after a meal, the real test is whether your fasting blood sugar is below 110 and if your blood sugar returns to below 110 after 2 hours (which yours does). The fogginess after a meal can be blood sugar related, but can also be food allergy.

      If you are looking for more information on normal blood sugar after a meal, try searching for Glucose Tolerance Test.

      • Vittorio November 6, 2011 at 10:23 pm - Reply

        Thank you very much, Dr, Scott!

  11. Rebecca October 18, 2011 at 11:45 am - Reply

    I’ve been combating issues with sugar on and off for the past year or so. I’ve gotten several blood tests done and they’re all negative. I’m thinking about getting a glucose tolerance test done to see how that goes…anyway, it seems that all this trouble started when I had what seems like a very bad reaction to the Mirena IUD I had in place for roughly 8 months. Suddenly I was having dizzy spells, panic attacks, etc almost immediately upon consuming anything with any sugar in it. This has mostly quieted down, but any attempt to reintroduce synthetic hormones to my system makes it flare again, and it takes months for it to go back to mostly normal. I’ve never gotten a conclusive answer from my doctor that the two are related – my reaction to synthetic hormones and sugar – so I’m still scared that it could be diabetes or something, even though I have no prior family history that I’m aware of. It’s also not something that happens every time I consume sugar – sometimes candy is ok, but sugary drinks are usually a big problem, and anything with caffeine in it. I’m extremely confused about what my body is doing.

    • Dr. Scott October 19, 2011 at 6:17 pm - Reply


      There is a fairly well known relationship between blood sugar and estrogen: they tend to make blood sugar control worse. It sounds to me, however, that you are really sensitive to synthetic estrogens. Panic attacks can happen when blood sugar drops very low (your body thinks low blood sugar is an emergency situation and releases adrenaline to get the blood sugar back up. Eating sugar is not natural for humans and you should be staying away from it anyway, but it sounds like when you combine sugar and hormones it is very bad for you.

      Best of luck,


  12. Jess October 17, 2011 at 3:29 pm - Reply


    I think I have an intolerance to sugar, but I’m not sure if I do. I get really really bad headaches after drinking sugary tea and fizzy drinks, eating chocolate and sweets. I thought it might be caffeine at first, as they were all in them, but after buying decaffeinated tea bags, I discovered that I still get major headaches after drinking tea. I’ve had a diabetes test, as well as a glucose test, and they all came back inconclusive of diabetes. My nan had, and died from, diabetes and so I’m conscious of the fact that I could have it. However, I don’t have the excessive urination or thirst symptoms, I just have the excessive hunger. Could I have developed diabetes since the last test or will I just have a strong intolerance to sugar?


    • Dr. Scott October 18, 2011 at 7:19 am - Reply

      Anyone who has a family history of diabetes should be extra careful about their sugar intake. There are a lot of steps from normal blood sugar control to diabetes and you could be some steps in and still have your blood sugar tests come back as normal (your body is good at compensating – for a while). Either way, the sugar you eat is probably not doing you any good so I would suggest you take steps to reduce or eliminate a lot of sugar from your diet.

      Best of luck!

  13. Becky October 12, 2011 at 5:48 pm - Reply


    Whenever I eat or drink anything with sugar I get a big headache instantly. Also when I drink water I get a headache as well. I understand the sugar issues, but what about water? Why would water give me a headache? Most of the time the headaches feel like someone is squeezing the sides of my head together, lots of pressure. What do you think? I’ve never been positive for diabeties.

    • Dr. Scott October 13, 2011 at 6:47 am - Reply

      Becky, it is not common to have headaches from drinking water, unless you are drinking a lot of water. I would suggest a trip to your doctor who can help you better than I can.


  14. kelfel September 25, 2011 at 9:06 pm - Reply

    My symptoms line up completely with those of a diabetic but my blood work has only shown strange levels once. Every time since then it has come back normal. I crave carbs and sugar, have actually seen a doctor for number of times I void each day, and had to stop buying bottle water b/c I was drinking the 24 case in a 48 hour period. I am currently suffering from a severe headache that I am fairly certain was caused by an ice cream cone. Can these tests be wrong? Is it possible to be sensitive to sugar and to not have it appear on your blood work? I was told to not intake so much water as a way to avoid urinating so much, but when I drink less I get dry mouth. Any thoughts would be appreciated.

    • Dr. Scott September 26, 2011 at 4:00 am - Reply


      I would suggest that you go through more extensive testing. Try asking for a glucose tolerance test and see how that comes out.

      You might just want to change your diet and follow the 30 Sugar Free Days plan and see how you feel when you stay away from sugar and the foods that act like sugar. You really have nothing to lose and if you stop needing so much water and your headaches go away, then you know you are on the right track.

      Best of luck!


      • Marc October 3, 2011 at 9:13 pm - Reply

        I never get headaches but the last few weeks I been getting a lot of them to the point where even taking Advil wasn’t helping. I blamed it on a few things like, staying up late, 1-2AM and waking up at 7:30- 8AM, I been doing this for like weeks, coffee because I notice once I had more then one cup, right after the first, I get a headache, laying long ways on my back without head and neck support my neck the next morning would be very tense and lastly white bread intake, bagels, French beget and ice cream. Not sure which one or if all is bad for me but I am willing to stop eating and sleeping like that until I stop having headaches. I get really exhausted right before the headache then I get the heavy weight headache, which steals my memory and makes me confused. Its been a few days now and I notice that something is working because I only had to take Advil once today around 3PM and its now 11 PM and I still don’t have a headache. Oh, also thought it might be ear infection because I feel some mild pain coming down my temple down to my jar and gums area then I get the major headache.
        But when it does come on, the pain gets me very grumpy / touchy to point where I can’t think!! Anyway, I am a super creative thinker and I am at my best when I don’t have these headaches. Please help me get my life back. Thank You!

        • Dr. Scott October 4, 2011 at 3:33 am - Reply


          Your headache sounds like a sinus infection, but you should go and have a doctor check it out to make sure.


  15. mary September 17, 2011 at 8:10 am - Reply

    I tend to wake up (or get woken up in the middle of the nigh) with a headache if I have anything with sugar in it before bedtime, so I try to avoid anything sweet at night. It seems like the more I avoid sugar, the more susceptible I am to getting headaches if I have even the slightest amount of sugary foods during the day. Does this make sense?
    Also, I use splenda as a sugar replacement in coffee, cereal, smoothies, etc. Lately I’m wondering if using that is negatively affecting me.
    I’ve had so many of these headaches that my doc decided to do an MRI. It was essentailly clean, but what they found is that I have “vascular irritation.” This makes me think that my blood vessels are always on the verge. Any suggestions?

    • Dr. Scott September 18, 2011 at 4:57 am - Reply


      It sounds like you are very sensitive to sugar. I would consider having a doctor test your blood sugar (especially if you have a family history of blood sugar problems: sometimes waking at night can be a blood sugar issue). As far as Spenda goes, it has been linked to headaches and I don’t think it is the best chemical to put in your body. I have a chapter on artificial sweeteners in my book, but you can also check out Sweet Deception, by Joesph Mercola, or here is a short article: The Complete Guide to Artificial Sweeteners

  16. Lisa September 2, 2011 at 12:59 am - Reply

    Hi. I get migraine headaches after eating processed sugar without a protein. If I eat a dessert immediately following a meal, I’m usually fine. If I eat processed sugar anytime during the day I get a migraine usually several hours later. Increasingly fresh fruit eaten alone can also bring on a headache, especially if eaten before sleeping. 800 mg.Ibuprofen usually will stop the headache if I catch it before it comes on strong. Blood tests have been inconclusive yet my doctor thinks it may be related to hypoglycemia. I’m in good physical shape and usually avoid all sugars to keep the headaches away. Any thoughts?

    • Dr. Scott September 2, 2011 at 5:23 am - Reply


      The reasons behind a sugar headache are mostly unknown, though I do have a few suspicions. What is clear from what you said is that any large spike in your blood sugar will bring on the headache. When you eat sugar with a meal, that keeps your blood sugar lower than when you eat it outside of a meal. And, yes, many fruits act like sugars in our body. Ultimately, I think our bodies just cannot handle the amount of sugar we put in them and that everyone has a different response to the overload of sugar we ingest (yours just happens to be a headache).

      Hope that helps!


  17. S August 4, 2011 at 3:12 am - Reply

    I have always had a sweet tooth since childhood. I loved my desserts and all kinds of sweet dishes but never over ate them. I am 27, have a healthy BMI and exercise regularly. But lately I have been getting headaches after eating something sweet (like a pastry and a soft drink). I checked my blood sugar and the doctor said there is nothing to worry about but I fail to understand the cause of these frequent headaches. I hope its not pre diabetes. I don’t get sugar cravings and try my best to control but at the super market things tempt me :(

    • Dr. Scott August 4, 2011 at 8:48 pm - Reply

      Your headaches sound like sugar overload, or it may be an allergic reaction to a food you are eating. Try staying away from sugar and foods that act like sugar and see how you feel.

      • S September 19, 2011 at 1:37 am - Reply

        Thank you for your advice. I stayed away from sugar all these days and I have not got a headache. If I eat something sweet along with meals like a dessert, its not a problem. But when I consume only sweets, the headaches are back.

  18. christina July 12, 2011 at 2:22 pm - Reply


    I know this was posted over a year ago but I am hoping I will get a response. I have been off sugar and unhealthy carbs for over 3 months and feel great! I also consume VERY LITTLE dairy. Only milk in my coffee and a small amount of skim milk or no fat cheese. Last night it was so hot out we all decided to go to Dairy Queen. I ate a half of a medium reeses pieces blizzard and feel like I have never felt so terrible in all my life. Before bedtime hit I had a major headache! I woke up this morning feeling hung over and achy and still had a slight head ache. I have been to the bathroom 4 times already and feel a little bit shaky. I have been eating only probiotics and chicken breast today along with drinking plenty of water and only now at 4pm am I starting to feel a little bit better but still have a mild headache. Could this have been a reaction to the dairy and sugar I consumed in this small amount of ice cream and sugar or should I go visit my Doctor?

    • Dr. Scott July 13, 2011 at 8:38 am - Reply


      Yes, this seems exactly like a reaction to the dairy and sugar. Lactose intolerance can cause the exact symptoms you describe.

      But I would say that if you aren’t feeling better by the time you read this, that you might want to go see your doctor, this could be an infection of some kind too. Either way, what you are looking to avoid is dehydration, so make sure you are getting enough fluids.

  19. sugerdaddy May 24, 2011 at 12:57 pm - Reply

    What do you mean by “excessive” urination? What is normal urination? My girlfriends thinks I have to go to the bathroom too often (sometimes a 2hr drive is difficult). But I think this mostly comes from either drinking water, which I do often, or worse; coffee, tea or an apple.

    I have had several diabetics in my family so I’m conscious of this. I eat very little sugar (never drink soda) and sometimes get a headache when I eat even small amounts of sweets, especially whipped cream.

    • Dr. Scott May 26, 2011 at 7:07 am - Reply

      Excessive may be hard to figure out. Someone else telling you that it is a problem is a hint. Sugar isn’t the only thing you have to look out for, you also need to watch out for the foods that act like sugar (mostly grains). Since you have a family history, I would go and get a simple blood test just to be sure.

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