9 Surprising Signs You Might Have A Sugar Intolerance

That sweet tooth isn’t doing you any favors.

Originally Published: 

If you have even the tiniest hint of a sweet tooth, you likely know the exact ins and outs of how indulging in sugary-sweet treats makes you feel — for better or for worse. Feel particularly terrible after a holiday party, night out, or one too many trips to the candy and donuts in the break room, and you might start to wonder if your body actually doesn't handle sugar all that well. While sugar allergies are possible, they're rare, but there are a lot of signs you have a sugar intolerance, which is more likely to be what's ailing you.

“Sugar can cause inflammation in the gut, which could cause an ‘intolerance’ like bloating, cramping, stomach pains, and possibly even a runny stomach,” registered dietician Danielle Venter tells Romper. Symptoms usually appear pretty soon after eating your sugary treats. Generally, the signs will show up about two hours later, but sometimes it can take four to six. “It depends on how much of the food the person ate, as a small amount may cause no reaction,” she explains. “Some symptoms like bloating or a headache can even take one to two days to show. Usually, in an elimination diet, we would wait 72 hours to see if any reactions occur.”

Can you be allergic to sugar?

What's the difference between an allergy and intolerance, anyway? "When a person is allergic to a food item, it’s not so much that they’re allergic to the sugar, but they’re allergic to some type of protein that’s in that food," Charmaine Jones, registered dietitian and founder of Food Jonezi, tells Romper. When this happens, your immune system attacks the protein because it thinks it’s a foreign invader like a virus or bacteria. The chemicals released to do the attacking can cause your body to break out in hives or have another kind of allergic reaction like swelling, tightening of the airway, shock, or a fast heart rate. Food allergies can be life-threatening. They're no joke.

Food intolerances, on the other hand, aren't usually life-threatening. "[I]f a person is food intolerant [to sugar] ... that means that your body is unable to or [has] problems digesting that sugar," Jones explains. That's not to say that food intolerances don't cause problems of their own, but they won't severely hurt you.

There are probably more things that can qualify as "sugar" than you realized. Lactose, maltose, dextrose, sucrose, and the like are all forms of sugar. The -ose suffix can help you figure out if something might be a sugar, so it's handy to keep that in mind when reading labels. If you think that you're intolerant to sugar or sugar alcohols — Jones says some people are extra sensitive to those as well — there are a few things you need to look out for. And your gut is at the center of it all.

Sugar intolerance symptoms


You're bloated

PixelsEffect/E+/Getty Images

Bloating is never comfortable. You just feel puffy and lethargic and, well, gross. If your body is struggling to digest a particular sugar, whether it's lactose or something else, it can cause you to bloat as that sugar tries to make its way through your digestive system, Jones says. If you tend not to notice when you feel bloated, the good news (or bad news) is that you'll likely have other, perhaps more noticeable symptoms as well. To combat this, Venter suggests gradually increasing fiber. “Eating more fiber helps to combat constipation and bloating,” she tells Romper. “Avoid fizzy drinks and chewing gum. Get active to get the gut moving!”


You get gassy

Excess gas can also be a sign that you're intolerant to sugar, as registered dietitian Vanessa Rissetto tells Romper. Taking medications that help alleviate gas might help mitigate the problematic symptom, but it won't help with the underlying intolerance, so you might want to avoid whatever sugar it is that resulted in you feeling slightly gassier than usual.


You have anxiety

Feeling more anxious lately? While you may not think that a sugar intolerance could be the cause, as naturopath Kristen Swales tells Romper, your anxiety actually could indicate that your body isn't handling an influx of sugar all that well. Cutting back on your sugar intake could help reduce anxiety and help you feel more grounded. Venter adds that alcohol and caffeine can also aggravate anxiety while regular exercise can help alleviate these symptoms.


You feel nauseated

Rissetto notes that nausea can also be indicator that you have a sugar intolerance, especially when paired with other gastrointestinal symptoms like gas and bloating. "In some cases, the best solution is avoidance," naturopathic physician Dr. Jennifer Stagg tells Romper. That can be a difficult proposition, but if it helps you feel better, it might be worth it.


You have a bag stomachache

Stomach cramping is never, ever comfortable — or easy to ignore. Sugar intolerances, like lactose intolerance, can cause intense stomach cramping, Jones remarks. It makes sense if you think about it. Your body can't digest sugar well, and so when it shows up in your digestive system, things go a little haywire. According to Stagg, "if it’s an issue with glucose regulation, then eating sugar as part of a meal containing fat and protein will slow down the absorption of sugar in the intestinal tract." Think about how you’re pairing your foods, as well as what you're specifically eating.


You crash after eating it

juanma hache/Moment/Getty Images

Surely you've experienced a sugar crash before, after eating a bit too much of it. According to Swales, however, major energy dips after you eat sugar might also indicate that your body isn't handling it well. If this is your only symptom, it doesn't necessarily mean for sure that you have a sugar intolerance, but it could be an initial hint that something is going on.


You deal with joint inflammation

Sugar causes inflammation, which isn't good for your body. Swales says that sugar intolerances can cause joint pain in particular, but it can also just cause inflammation in general. "Inflammation is an underlying factor in most chronic diseases," Stagg says. For that reason, it's important to be cognizant of how much sugar you're eating, whether you're intolerant to it or not.


You're not sleeping well

Sleep is super important for your overall health, but, annoyingly, there are a lot of things that can interfere with it — whether it's too much caffeine, a lumpy mattress, or a baby that requires your middle-of-the-night attention. According to Swales, a sugar intolerance can also cause you to experience night sweats. Night sweats are uncomfortable and embarrassing, and they can leave you exhausted in the morning.


You get a little shaky

'There are a wide range of symptoms that can happen if you are not tolerating sugar well — you could experience hyperactivity or shakiness a while after eating foods high in sugar," Stagg says. If you feel shaky — not just energized — after eating sugar, it might mean your body doesn't handle it well. Looking at the type of sugar you eat, the amount, what you eat it with, and how you eat it might help you feel better. But as Jones emphasizes, seeing a doctor or allergist and working with a dietitian are the best ways to not only know for sure if you have an allergy or intolerance, but manage it, too.

There are a lot of signs to look out for if your think you may have a sugar intolerance that go beyond a simple sweets-induced headache. The best way to really test out what’s causing any annoying symptoms is an elimination diet — if you feel better cutting out sugar, it may be a sign your body does not love trying to digest the stuff due to an intolerance.


Danielle Venter, registered dietician

Charmaine Jones, registered dietitian and founder of Food Jonezi

Vanessa Rissetto, registered dietician

Kristen Swales, naturopath

Dr. Jennifer Stagg, naturopathic physician

This article was originally published on