Why Diarrhea Happens After Fasting and How to Manage It

Why Does Diarrhea Happen After Fasting? Causes and How To Manage It

It's not uncommon to develop loose, watery stools or full-blown diarrhea after an extended fast. This abrupt change in bowel habits occurs due to the impact fasting has on your gastrointestinal system.

Understanding the reasons behind post-fast diarrhea can help you take steps to minimize or manage this common side effect.

What Causes Diarrhea After Fasting?

Going without food for an extended time can disrupt the balance of gut bacteria, digestive enzymes, and fluid absorption in ways that allow diarrhea to develop. Causes include:

• Altered gut flora - Fasting dramatically changes the bacteria in your intestines, leading to excess gas and diarrhea.
• Low enzyme levels - Long fasts deplete digestive enzymes needed to properly break down foods.
• Irritation from toxins - When fasting, your intestines release stored sugars, fats, and toxins that can irritate the bowel.
• Osmotic effects - Intestinal fluids pull water into the bowels due to particles released from fat breakdown.
• Overactive intestines - Fasting can overstimulate the enteric nervous system and motility in the gut.

How Fasting Impacts Bowel Habits

Fasting sets off a cascade of shifts in digestive function and gastrointestinal motility:

• As you fast, levels of the hunger hormone ghrelin rise, stimulating intestinal contraction.
• Migrating motor complexes that sweep digestion along the gut speed up during fasting periods.
• Production of digestive enzymes like lipase, amylase, and proteases decreases significantly without food intake.
• Populations of gut microbes are altered, allowing gas-producing bacteria to flourish.
• The intestines secrete excess serotonin, inducing secretory diarrhea.

These changes prime the intestines to be hypersensitive and over-reactive once you start eating again after fasting.

Factors That Increase Your Risk of Post-Fast Diarrhea

You may be more prone to diarrhea and gastrointestinal distress after fasting if you:

• Have pre-existing irritable bowel syndrome (IBS) or inflammatory bowel disease
• Took laxatives or diarrhea medications during your fast
• Consumed only Clear liquids like juice, soda, broth during your fast
• Have recently taken antibiotics that altered your gut flora
• Broke your fast with trigger foods high in fat, fiber or sugars
• Have gut bacterial overgrowth or food intolerance issues
• Have had gastrointestinal surgery in the past

How to Minimize Diarrhea After Fasting

While some diarrhea is expected after not eating for many hours or days, you can take steps to help control it:

1. Gradually Break Your Fast

Abruptly switching from fasting to eating normal meals is a recipe for digestive turmoil. Instead, ease out of fasting mode gently over 12-24 hours. This gives your gut time to ramp up enzymes and adjust.

Start with clear liquids like water, herbal tea, or broth. Move on to bland smoothies, yogurt, rice, and applesauce before resuming regular meals.

2. Avoid Trigger Foods

Your first meal after fasting should be easy on the intestines. Avoid spicy, greasy, or fat-laden foods. Say no to dairy, beans, cruciferous veggies, and anything with added sugars.

Stick to cooked grains, non-fibrous vegetables, lean proteins, and broth-based soups until bowel movements normalize.

3. Stay Hydrated

Drink plenty of water and electrolyte beverages like coconut water after fasting to prevent dehydration and constipation. Peppermint or ginger tea can relax the gut.

Avoid alcohol, coffee, and sugary sodas, which stimulate bowel movements.

4. Take Probiotics

Probiotic supplements can help restore beneficial bacteria to rebalance your gut microbiome after fasting. This assists with healthy digestion and immunity.

Yogurt, kimchi, sauerkraut, and kefir also provide probiotics. But start slowly with fermented foods until your bowel habits stabilize.

5. Consider Digestive Enzymes

Over-the-counter enzyme supplements provide lipase, protease, and amylase to help break down fats, proteins and carbs. This takes pressure off your depleted digestive enzymes after fasting.

Look for broad-spectrum enzyme blends to support overall digestion.

What to Do If Diarrhea Persists After Fasting

It's normal to have some loose BMs for 2-3 days after ending a fast. But ongoing diarrhea or severe symptoms warrant medical care. See your doctor if you experience:

• Diarrhea lasting more than 3 days post-fast
• Black, bloody, or tarry stools
• Intense intestinal cramping or bloating
• Nausea, vomiting, or inability to keep liquids down
• Dehydration symptoms like excessive thirst, dizziness, or dark urine
• Severe abdominal pain
• High fever, chills, or signs of infection

Signs of dehydration or infection require prompt medical treatment with IV fluids and possibly antibiotics.

See Your Doctor If You Have Ongoing Fasting Diarrhea

Make an appointment with your healthcare provider if you have frequent bouts of diarrhea after fasting. They can check for underlying causes like:

• Bacterial overgrowth - Excess bacteria in the small intestine can cause chronic diarrhea after fasting.
• Gallbladder issues - Fasting can trigger gallbladder contractions and diarrhea in people with gallstones.
• Parasites - Some intestinal parasites flourish after fasting.
• Celiac disease - Fasting and refeeding can unmask gluten intolerance or celiac disease.
• Inflammatory bowel diseases - Conditions like Crohns or ulcerative colitis may worsen with fasting.
• Irritable bowel syndrome - Fasting can trigger IBS flares.

Your doctor can order stool tests, breath testing, or endoscopies to identify any underlying problem causing chronic post-fast diarrhea.

When Fasting May Not Be Right for You

Fasting does not agree with everyones digestive system. You may opt to avoid extended fasting if you have:

• Irritable bowel syndrome or inflammatory bowel disease
• Gastroparesis or slow stomach emptying
• A history of eating disorders
• Severe GERD or gastric ulcers
• Gallstones or gout
• Low blood pressure
• Brittle diabetes
• Kidney disease

Talk to your healthcare provider before attempting intermittent fasting if you have chronic gastrointestinal issues.

Disclaimer: This article is for informational purposes only and does not constitute medical advice. Always consult with a healthcare professional before starting any new treatment regimen.