Diarrhea After Eating Sugar - 7 Possible Reasons It's Not All In Your Head

7 Possible Causes of Diarrhea After Eating Sugar

“7 Possible Causes of Diarrhea After Eating Sugar” was written by dietetic intern and Certified Personal Trainer Julie Wilcoxson, B.S. and reviewed, edited and updated by Jenna Volpe, RDN, LD, CLT.

Have you found yourself rushing to the restroom after eating a sugary treat? It may seem unusual – but you may actually be onto something. 

Experiencing diarrhea after eating sugar isn’t normal, but it’s possible – and it certainly doesn’t just happen for no reason.  (That’s right – these things aren’t just “all in your head”!)

In this article we’ll delve into the 7 most common reasons sugar can potentially cause diarrhea.

Disclaimer: This article was written for general education purposes, not to be taken as medical/dietary advice! Consult a registered dietitian and/or holistic and functional nutritionist to receive custom advice tailored to your individual needs.

Affiliate disclosure: This post contains affiliate links. As an Amazon associate, Whole-istic Living may receive a commission on qualifying purchases, at no extra cost to you.

What is considered diarrhea?

Diarrhea is defined as loose, watery stools – with or without a sense of urgency.

An occasional bout of diarrhea isn’t usually a cause of concern.  

But if you notice you’re having diarrhea frequently after eating specific foods, it’s worth investigating, or you could eventually end up with dehydration, nutritional deficiencies, malnutrition, fatigue and more.

If you process information visually, checking out the Bristol Stool Scale can be quite helpful!  (Diarrhea according to the Bristol Stool Scale means your bowel movements resemble a Type 5, 6, or 7.)

Why would sugar cause diarrhea?

There are generally dozens of potential underlying causes of diarrhea, but not all of them would be triggered by sugar. 

(Sugar aside, make sure you’re working with a qualified doctor and functional medicine practitioner who can help you figure out the root causes of your diarrhea!)

In our experience, from a clinical and holistic nutrition standpoint, the 7 most common reasons for diarrhea caused by sugar may be any of the following: 

  1. Dumping syndrome (caused by gastric surgery or certain medications)
  2. Sucrose intolerance (caused by a sucrase-isomaltase deficiency)
  3. Fructose intolerance (caused by a genetic mutation OR small intestinal bacterial overgrowth)
  4. Candida overgrowth / dysbiosis (gut microbial imbalance)
  5. Too much sugar at one time (i.e. overeating or binging)
  6. A food sensitivity to sugar, honey, or maple syrup 
  7. You’re reacting to something else!

1: Dumping syndrome

“Dumping syndrome” happens when high-sugar food rapidly “dumps” from your stomach into your small intestines, resulting in rapid gastric emptying.  

(For reference, “dumping syndrome” = the opposite problem as delayed gastric emptying!)

Dumping syndrome is a risk for people who have had bariatric surgery, some or all of their bowel (intestine/colon) surgically removed, and some people who are taking glucagon-like peptide- 1 (GLP-1) medications. (1)

What’s sugar got to do with it?

Gastric procedures and certain medication will alter (reduce) your gut’s transit time. 

So high-sugar foods that “dump” too quickly into your lower bowel are more likely to pull water in by osmosis.

This dumping mechanism usually leads to symptoms of cramping, gas, bloating, abdominal pain, and diarrhea.

Additional symptoms of dumping syndrome may also include nausea and chills.

Types of dumping syndrome 

Dumping syndrome can occur within 30 minutes of a meal, known as “early dumping”, or up to 3 hours after, referred to as “late dumping”.  

How it works:  Your digestive system is responsible for hormone production which can impact fluid movement in your gut.

Early dumping

If food passes through your gut too rapidly, it can create an increased hormone release, which pulls fluids into your small intestine. This causes early dumping.

Late dumping

In contrast, this surge in hormones may force your pancreas to produce more insulin (a hormone that helps metabolize sugar), contributing to late dumping. 

What you can do

To mitigate the occurrence of dumping syndrome, consider adopting a few practices. 

Chew your food thoroughly

If you’re prone to dumping syndrome, we recommend chewing your food thoroughly (to applesauce consistency, whenever possible) to help increase digestive secretions and reduce the digestive burden on your gut.

Eat slowly

Eating meals at a slower pace allows your stomach’s digestive secretions a little extra time to properly break down food. 

  • For example, stomach acid (aka “hydrochloric acid” or “HCI”) helps to digest foods.  When we eat too quickly, our body doesn’t have enough time to produce adequate amounts of HCI. (2)
Go for small, frequent meals/snacks

Eating smaller meals/snacks more frequently is another way to keep sugar intake lower, while reducing the overall digestive burden on your gut.

Lean on protein

Incorporating a protein source (such as chicken, turkey, beef, eggs, etc) alongside meals (and alongside a sugary treat) can help slow down the breakdown of sugar in your gut, lowering your risk of diarrhea caused by dumping syndrome. (3)

Switch to alternative sweeteners

If you love sweets, but sugar is not your friend, it may be worth exploring non-nutritive sweeteners.  

(As holistic practitioners, we generally prefer more natural alternatives like monk fruit and stevia leaf extract – especially from a gut health standpoint.)

Related articles:

2. Sucrose intolerance

Sucrose intolerance, a type of adverse food reaction caused by a sucrase isomaltase enzyme deficiency, is a condition where your digestive system struggles to break down or absorb sucrose (table sugar) from foods.

If you happen to have a sucrase-isomaltase deficiency (and a subsequent sucrose intolerance), eating sugar is going to likely trigger diarrhea and other symptoms of sugar malabsorption such as gas, bloating, abdominal pain, and/or nausea/vomiting.  

(Eating sugar with a sucrose intolerance is comparable to drinking a glass of regular with lactose intolerance.)

There are two types of sucrase-isomaltase deficiency:  genetic (congenital) and acquired (caused by another condition which has damaged the brush border of your intestine).

Recommended reading: 

What can you do?

Test, don’t guess!

If you’ve noticed diarrhea after eating sugar (and other low FODMAP high-sucrose foods like real maple syrup, pineapple, and carrots, too), consult a CSID-informed gastroenterologist (GI doctor) about testing.

Option 1:  Intestinal biopsy with sucrase enzyme assay

Right now the “gold standard” test for diagnosing a sucrase-isomaltase deficiency is unfortunately a bit invasive.

  • How it works:that you need an endoscopy or colonoscopy, where your doc will directly measure and analyze your sucrase enzyme production via an intestinal biopsy. (4)
Option 2:  Sucrose breath test

A less invasive option for detecting sucrose malabsorption is the 13C-sucrose breath test. (5)

  • This is a diagnostic at-home test in which you breathe into a tube over the course of a few hours.  The gasses produced by your breath will confirm or rule out a sucrose malabsorption.

Sucrose intolerance diet

If you do have a sucrose intolerance, reducing or eliminating foods high in sucrose can potentially bring significant relief from diarrhea. 

Recommended reading: 

Additional helpful sucrose intolerance / “sugar intolerance” diet resources:

Enzyme replacement therapy

If you do have a sucrose intolerance, a low sucrose elimination diet will most likely help reduce symptoms drastically – but it’s also extremely restrictive!

Enter: enzyme replacement therapy.

Two specific proprietary enzymes have been shown to help aid in the digestion of sucrose and sugar:

  1. Sacrosidase (trade name: Sucraid®)
  2. Starchway by Intoleran

They aren’t 100% effective,  but they’re worth trying and they can potentially make a positive difference in your quality of life! 

(Remember to consult your CSID-informed doctor and gut health dietitian 1-1 for custom advice.)

3. Fructose intolerance

Fructose is a form of sugar naturally found in many types of fruit, as well as in certain sweeteners (such as honey, agave nectar, and high fructose corn syrup).

Much like sucrose intolerance, a fructose intolerance has very similar symptoms like diarrhea, gas, bloating, nausea, and/or abdominal cramping.

If you notice you’re having diarrhea after eating high-fructose “sugary” foods such as honey, agave nectar, and high fructose corn syrup, or even fruits high in fructose,  it may be worth investigating and ruling out fructose intolerance.

Types of fructose intolerance


In rare cases, a fructose intolerance could be lifelong and hereditary, caused by a genetic mutation which interferes with enzyme production specifically for the digestion and breakdown of fructose. (6)


Nowadays, we’re seeing more cases of fructose intolerance (along with other FODMAP intolerances) develop secondary to intestinal issues like small intestinal bacterial overgrowth (SIBO) left unchecked.

This is because fructose also happens to be a high FODMAP ingredient in foods.

  • The “FODMAP” acronym stands for “Fermentable Oligosaccharides, Disaccharides, Monosaccharides And Polyols which are different types of carbohydrates that generally don’t get easily digested or absorbed as well in our intestines. 

What can you do?

Consult with your doctor and a gut health dietitian

It’s important to run the right tests to make sure you’re properly addressing and treating your digestive issues from a root-cause level.

A gastrointestinal (GI) doctor can help with running tests to help you pinpoint WHY you’re getting diarrhea after eating sugar.

A registered dietitian specializing in gut health can provide tailored advice and feedback around any patterns and support you in navigating your adverse food reactions.

Low fructose diet

In cases of a fructose intolerance, on the level of symptom management, try to reduce or limit the amount of high fructose foods in your diet. 

  • Read food labels for ingredients like high fructose corn syrup, honey, and/or agave nectar.
  • MONASH University has a great app to use as a resource for recognizing high fructose foods such as certain types of fruit or foods sweetened with a type of high fructose sugar.
Digestive enzymes

Did you know there are specific enzymes on the market that can help you to break down fructose in foods more effectively?

Here are a few of our faves:

  1. FODZYME* (enter code WHOLEISTICLIVING to get 15% off your first order!)
  2. Fodmate*
  3. Fructaid*

Again, make sure you’re consulting with your treatment team and not self-prescribing. 

Recommended reading:

4. Candida overgrowth / dysbiosis

Candida is a type of opportunistic yeast which naturally lives in our body as part of our “microbiome”, but which must be kept under control.

  • The microbiome = our unique ecosystem of microbes which dwell mostly in our gut, impacting aspects of our digestion, immunity, mental health, skin, hormone balance, and more.

While candida is considered generally safe and healthy, it can pose an issue when it over-grows out of control, leading to potential problems – often including diarrhea. (7)

(Candida overgrowth can often happen when our gut microbiome is not diverse enough, since the probiotic microbes are supposed to serve as our first line of defense against invaders!)

What does sugar have to do with it?

Some research studies and leading experts in integrative and functional medicine are suggesting that large quantities of refined sugar in the diet can potentially feed the overgrowth of Candida. (8, 9)

Recommended reading:  

(While this is still considered controversial, since not all research supports this theory, it’s worth considering, especially since we’ve anecdotally observed people with confirmed candida overgrowth report that diarrhea symptoms improve with this type of dietary modification.)

What can you do?

There are some very specific lifestyle factors that may help to get your microbiome back into balance, when it comes to candida-induced diarrhea!

Address stress

Stress negatively impacts our immune system, which impacts our resilience against candida and other pesky microbes in our gut. 

Adopting personalized stress reduction behaviors, such as yoga, spending time in nature, or practicing deep breathing, can benefit the relaxing of the body and mind.

Reduce sugar consumption

Sugar is generally a preferred food source for yeast and fungi.  Restricting this fuel supply can make it easier for your body to regain equilibrium, ultimately inducing candida overgrowth.

Incorporate probiotic foods/supplements

Beneficial probiotic bacteria strains, such as Lactobacillus (found in many probiotic functional foods), may help with crowding out candida overgrowth. (10)

Consult a functional nutrition / functional medicine practitioner 

Did you know it’s possible to identify (and treat) candida and dysbiosis holistically?

In the field of integrative and functional medicine, as well as in functional nutrition, practitioners can run comprehensive stool testing such as the GI MAP test,

There’s also an entire class of herbs with natural antifungal/antimicrobial properties, shown to help effectively eradicate this type of functional overgrowth. 

You can work with a clinical herbalist and/or a functional dietitian nutritionist to receive custom protocols based on what’s going on in your gut.

5. Food sensitivity to sugar

In rare cases (especially alongside leaky gut), it’s possible to have a food sensitivity sugar.

(Note that a food sensitivity is different from an allergy or intolerance, and can manifest in a wide spectrum of ways beyond just diarrhea.)

People with a sensitivity to sugar are usually also dealing with a slew of other food sensitivities and inflammation, and need to go deeper than just removing sugar from their diet.

What can you do?

Food sensitivity testing isn’t for everyone, due to the increased risks that accompany dietary restriction.

Consider consulting with a certified LEAP therapist to get a better understanding of whether or not running a Mediator Release food sensitivity test is right for you as a component of a bigger holistic protocol for diet-induced inflammation.

Recommended reading:

6. Too much food at one time 

Food for thought:  What if it isn’t the sugar, but the quantity of what happens to be a sugary food at one time, that’s causing your diarrhea?

We’ve all experienced the tantalizing aromas and flavors of freshly baked, irresistible chocolate chip cookies (or brownies, or cake, or whatever’s your jam) – and sometimes, it’s hard to resist having more than one.

Overindulging in a large volume of food in a relatively small window of time can potentially trigger the release of more fluids into your intestines, ultimately leading to that urgent feeling to use the restroom. (11)

While this scenario isn’t exclusive to sugary foods, it’s generally more common to overeat (or even binge on) sugary foods, since they’re relatively low in fiber – and so tasty!

But technically, any type of food consumed in large quantities in a short span can potentially cause a similar outcome of diarrhea and upset stomach.. 

What Can You Do?

Don’t skip meals

Eating 3 balanced meals a day (and maybe even a few snacks) can go a long way to keep blood sugar levels balanced, which helps reduce any urges to binge on sugary foods.  

(Typically binging or over-indulging in high-sugar foods is more likely to happen when blood sugar levels are running low!)

Mindful eating

The practice of mindfulness – aka slowing down your pace when eating, being conscious of both the speed and quantity of the meal in one sitting, can go a long way to help keep portions more aligned with your digestive capacity.

Give yourself permission to savor and enjoy every bite of delicious food! 

Chew your food thoroughly 

Taking the time to chew your food thoroughly is another helpful way to pace yourself during meals. (Think: chew x32 times, or to applesauce consistency. Easier said than done, but usually worth it!)

Aside from slowing down your pace, chewing food helps with digestion by stimulating the release of digestive secretions, while reducing the overall digestive burden on your gut.

Recommended reading:  The Scary Link Between Disordered Eating and IBS

7. You’re reacting to something else

In some cases, when it comes to sugar and diarrhea, it’s worth considering that you may be reacting to something else in a sugary treat – rather than the sugar itself. 

For example, gluten, wheat, lactose, and dairy are top-of-mind when it comes to common food triggers of diarrhea that often overlap with sugar in foods.

What you can do

Keep a food-symptom journal

If you’re unsure of which foods are triggering diarrhea, consider keeping a detailed food-symptom journal (and consult with a gut health dietitian) to identify patterns.

Consult an expert

As always, consulting 1-1 with a gut health dietitian can make your life a whole lot easier!  

Recommended reading:

Diarrhea After Eating Sugar - 7 Nutrition-Related Root Causes to Consider - Pinterest Image

Frequently asked questions (FAQ’s)
Will too much sugar cause diarrhea?

Generally, most people can consume sugar without experiencing diarrhea. 

However, you may want to consider the following exceptions in which sugar can trigger diarrhea (as previously discussed earlier):

  • Dumping syndrome
  • Sucrose intolerance
  • Fructose intolerance
  • Candida overgrowth / dysbiosis
  • Food sensitivity to sugar
  • Binging on sugary foods
  • Reacting to something else

Is sugar low FODMAP?

It depends on the type of sugar!  

For example, table sugar (sucrose) and invert sugar from beet sugar, cane sugar, and evaporated cane juice are considered low FODMAP. 

However, according to the MONASH University FODMAP App, fructose (the main sugar in honey, high fructose corn syrup, and some fruits) is considered a high FODMAP sugar.

(Get a comprehensive list of low FODMAP sugars and sweeteners here.)

Can sugar trigger IBS?

Being low in FODMAPs, “table sugar” (aka sucrose, beet sugar, and cane sugar) will not typically trigger irritable bowel syndrome (IBS) symptoms  in most people.

The only cases in which sugar can directly trigger IBS-like symptoms (such as diarrhea, gas, bloating, nausea, and/or abdominal cramping) are in cases of sucrase-isomaltase deficiency and/or a fructose intolerance (since fructose is a high FODMAP form of sugar).

Is sugar bad for IBS? 

The simple answer is no, at least from a symptom management standpoint, because table sugar is low in FODMAPs. 

However, from a holistic health standpoint, there’s more to consider:

  • Is there something else going on, like an enzyme deficiency and/or microbial overgrowth? 
  • Or perhaps your IBS symptoms are being triggered by other foods accompanying the sugar?

Consult with a qualified functional and integrative medicine provider who can help you uncover the root cause(s) of your IBS, so you can then determine which foods will be best for you on your journey.

Does sugar feed candida? 

This is a difficult question to answer because the research isn’t as clear on it. 

As mentioned earlier, some studies show that sugar is a preferred food source for candida yeast/fungus. (8, 9)

However, in a 1999 study, the verdict  was that there was no correlation between the two. It showed there was no increase in candida following a high refined carbohydrate diet. (12)

When in doubt, consult a functional nutrition practitioner to receive testing and guidance!

More related articles & recommended reading

Sugar and diarrhea, recapped

Diarrhea is a bothersome issue and can lead to serious issues if left untreated. Frequent bouts of diarrhea can lead to dehydration, vitamin/mineral deficiencies and malnutrition.

If you suspect sugar is causing diarrhea, consult a holistic-minded healthcare provider who can help you investigate and determine whether it’s related to dumping syndrome, a sucrose intolerance, fructose intolerance, enzyme deficiency, microbial overgrowth, and/or a food sensitivity to sugar. 

Keep in mind diarrhea can also result from other types of food intolerances/sensitivities and/or overeating, verses from the sugar itself.

No matter which route you go, healthy foundational mealtime habits can go a long way to improve your digestion!

Next Steps

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