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Is it normal to have diarrhea after smoothie?


Smoothies are often touted as a nutritious and delicious way to get more fruits and vegetables into your diet. However, some people report experiencing diarrhea after consuming smoothies. Diarrhea can occur for several reasons, but is most commonly caused by the ingredients used in the smoothie or an intolerance to a specific ingredient. Understanding the potential causes of diarrhea from smoothies can help you determine if this is a normal reaction for you or a sign that you may need to modify your smoothie recipe.

Common Causes of Diarrhea from Smoothies

Here are some of the most frequent reasons smoothies may lead to diarrhea:

1. Fructose overload

Many smoothies have a very high fructose content. Fructose is the natural sugar found in fruits. It is far sweeter than sucrose (regular table sugar). While small amounts of fructose are generally well tolerated, consuming excessive amounts can overwhelm the body’s ability to absorb it properly in the small intestine. The unabsorbed fructose then travels to the large intestine, pulling water with it and causing diarrhea. Very sweet, fruit-based smoothies are most likely to cause issues due to fructose overload.

2. Fiber content

Smoothies are often packed with high fiber ingredients like leafy greens, flaxseeds, chia seeds, and psyllium husk. Fiber is healthy and important for digestive regularity. However, dramatically increasing your fiber intake over a short period can lead to diarrhea. This reaction tends to be temporary as your body adjusts to the increased fiber content.

3. Lactose intolerance

Many smoothies include dairy products like milk, yogurt, or ice cream. People with lactose intolerance lack sufficient levels of the enzyme lactase needed to properly digest lactose, the natural sugar in dairy. Undigested lactose in the intestine pulls in fluid, causing diarrhea. Even small amounts of dairy can trigger symptoms in those with lactose intolerance.

4. Food poisoning

Contaminated ingredients can potentially introduce foodborne pathogens like salmonella, E. coli, and listeria into your smoothie. Typical food poisoning symptoms include nausea, vomiting, abdominal cramps, and diarrhea. Properly washing produce, keeping dairy refrigerated, and using unspoiled ingredients minimizes this risk.

5. Food intolerances and allergies

Some individuals may have undiagnosed allergies or intolerances to specific smoothie ingredients. For example, diarrhea and other GI symptoms are common with soy or whey protein intolerance. The most likely culprit ingredients are new additions to your normal smoothie recipe. Removing the problematic ingredient should resolve diarrhea caused by a food allergy or intolerance.

Ingredient and Recipe Considerations

Adjusting your smoothie ingredients and recipes can help reduce the chances of diarrhea as a side effect. Consider the following tips:

Limit added sugars

Avoid adding table sugar, honey, syrups, or other sweeteners which increase the total fructose content. Rely on the natural sweetness of fruits instead.

Reduce high fiber ingredients

Temporarily cut back on chia, flax and other seeds. Also use greens like spinach in moderation until your body adjusts to the fiber load.

Limit high FODMAP fruits and vegetables

Certain fruits and vegetables are high in FODMAPs, types of carbohydrates that can cause digestive issues in some people. Apples, pears, mangoes, dried fruits, garlic, onions, and cauliflower are examples.

Use lactose-free milk or yogurt

Substitute regular dairy products with lactose-free varieties if lactose intolerance could be causing your symptoms.

Avoid problem ingredients

If you suspect a specific ingredient is giving you trouble, remove it from your smoothie recipe for a few weeks and monitor your symptoms.

Stick to simple recipes

More elaborate smoothies with many ingredients make it harder to pinpoint the problematic culprit. Scale back to simple recipes with few ingredients.

Drink smaller smoothies

Large or giant smoothies maximize your exposure to potential irritants. Downsize your portions until your tolerance improves.

When to See a Doctor

Diarrhea lasting more than a couple days warrants a trip to your doctor. Seek medical advice if you experience:

– Diarrhea persisting longer than 2-3 days
– Severe pain or cramping
– Blood or mucus in stool
– Fever over 101 F
– Signs of dehydration like dizziness, dry mouth, or dark urine

These symptoms could indicate an underlying medical condition requires treatment beyond simple dietary changes. Your doctor can evaluate your symptoms, recommend any needed testing, and advise how to get your diarrhea under control.

Tips for Managing Smoothie-Induced Diarrhea

Here are some tips to help overcome diarrhea caused by your morning smoothie:

Take a smoothie break

Stop drinking smoothies for a few days to give your GI tract a rest. Reintroduce them slowly to identify ingredients you tolerate.

Adjust smoothie ingredients

As outlined earlier, modify your recipe to avoid ingredients that seem to provoke diarrhea.

Try probiotics

Probiotic supplements support healthy gut flora and may ease diarrhea in some cases. Ask your doctor for a recommendation.


Stay well hydrated by drinking water, broth, or electrolyte drinks. Avoid sugary sodas or juices with diarrhea.

Eat the BRAT diet

Stick to bland foods like bananas, rice, applesauce and toast for a day or two until diarrhea improves.

Avoid caffeine and alcohol

Caffeine and alcohol can make diarrhea worse by stimulating intestinal motility or causing dehydration.

Food Reason to Avoid with Diarrhea
Apple juice High in fructose which can worsen diarrhea
Beans and lentils High fiber can exacerbate diarrhea
Caffeinated drinks Can stimulate intestinal motility
Dairy products May contain lactose which is poorly digested
Fatty and fried foods Difficult to digest and can worsen diarrhea
Nuts and seeds High fiber content
Spicy foods Can irritate the intestines
Sugary foods and drinks Can worsen diarrhea caused by excessive fructose
Alcohol Dehydrating and irritating to the intestines

When to See a Doctor

While short-term diarrhea from your morning smoothie can be normal, chronic or severe diarrhea warrants medical investigation. See your doctor if you experience:

– Diarrhea lasting more than 2-3 days
– Severe abdominal pain, cramping or bloating
– Blood or mucus in the stool
– Fever over 101°F
– Signs of dehydration including dizziness, increased thirst, headache, and dark yellow urine

These symptoms may indicate an underlying condition like food allergy, IBS, IBD, or infection requiring treatment beyond simple diet changes.

The Bottom Line

It’s fairly common to experience some diarrhea when you first increase fiber intake or consume ingredient your body isn’t accustomed to digesting. Try adjusting your smoothie recipe, ingredients, and portion size to see if that helps resolve your diarrhea. But if symptoms persist or are severe, seek medical advice to rule out other causes. Pay attention to your body’s signals to determine if that initial bout of smoothie-induced diarrhea is just an adjustment period or sign of a deeper issue needing further evaluation.


In summary, diarrhea after consuming a smoothie can occur due to a variety of reasons, from ingredient sensitivities to sudden increases in fiber intake. Mild diarrhea that resolves quickly when modifying smoothie recipes is usually not a major concern. However, persistent or severe diarrhea may indicate an underlying health condition requiring medical assessment. Speak to your doctor if smoothie-associated diarrhea does not resolve within 2-3 days or is accompanied by concerning symptoms like blood in stool, fever, or dehydration. With some trial and error, most people can find a smoothie recipe and ingredient combo that provides all the nutritional benefits without the unwanted side effect of diarrhea.