Intolerance of Fried Fatty Foods
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Why Do Fried Foods Make Me Sick?

Why Do Fried Foods Make Me Sick?
Simon Belcher/Getty Images; Everyday Health
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Updated on August 6, 2025
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Fried fatty foods are a staple for many people, especially in the United States. A grease intolerance can make eating these foods uncomfortable and even painful, and may indicate another underlying medical condition.

Fast food is just one common source of fatty, fried foods in the Western diet. Between August 2021 and August 2023, 32 percent of adults in the United States ate fast food on any given day.

Fatty Food Intolerance

Food intolerance is a condition that occurs when your body is unable to properly digest food. Symptoms include:

  • Stomach pain or cramps
  • Bloating and gas
  • Nausea
  • Heartburn
  • Diarrhea
  • Headaches

The severity of your symptoms may vary. In some cases, individuals may be able to eat small portions of the offending food without consequence, while others may need to remove the food from their diet completely to avoid symptoms.

Food intolerance symptoms can be uncomfortable, but in some cases, food can trigger an allergic reaction in your system. If you suspect you have a food allergy, consult your doctor. Symptoms of a food allergy may include:

  • Hives
  • Itchiness or swelling of the skin
  • Vomiting
  • Diarrhea
In extreme cases, you may experience anaphylaxis, which can cause difficulty breathing or loss of consciousness.

Anaphylaxis is a serious, potentially fatal condition that requires immediate medical attention.

Histamines from food are one potential cause of food intolerances. Lower histamine levels typically trigger less of a reaction. Some raw foods, including cheese, sausage, wine, tuna, and mackerel, have high histamine levels. In some cases, cooking foods can alter the histamine levels.

The most recent research, published in December 2017 in Annals of Dermatology, notes that frying food can significantly increase histamine levels in some cases. In this study, a significant increase was seen in carrots and seaweed. In contrast, the histamine levels of eggs did not significantly change after frying. The study also notes that dairy cheese had significantly higher histamine levels than fresh milk.

Indigestion and Fatty Foods

Dyspepsia, or indigestion, may occur when you have a fatty food intolerance and eat greasy foods. High-fat foods, as well as spicy, high-fiber, or highly acidic foods, are difficult for your body to digest.

Other potential causes of indigestion include alcohol consumption, lack of sleep, and taking certain medications. Indigestion may also be a symptom of a more serious medical condition, such as a stomach ulcer, gallstones, or irritable bowel syndrome. If indigestion lasts for more than two weeks or if you experience additional symptoms such as bloody stool, vomiting, chest pain, or cold sweats, contact your doctor immediately.

Fat ingestion often increases the frequency of functional dyspepsia, or indigestion, with an unexplained cause. Functional dyspepsia is characterized by fullness, bloating, and nausea.

The reason for this sensitivity is unknown, but researchers speculate it may be related to hormones released in the gastrointestinal tract. It may also be due to slower digestion, in which food does not move as quickly from the stomach to the small intestine.

Excess cholesterol in the bile increases the risk of painful gallstones forming, so reducing your intake of fatty foods is a good idea in this respect.

 Also, if you have surgery to remove your gallbladder, bile is less concentrated and drains more frequently into your intestines (since gallbladders collect and concentrate bile), causing diarrhea. Bigger amounts of fat are harder to digest and can also cause diarrhea, so fatty foods should especially be avoided if you’ve had this surgery.

Fat Malabsorption Food Intolerance

Malabsorption of fat or other nutrients may be another cause of intolerance to fatty foods. This condition occurs when nutrients are not properly absorbed in the intestines. If the pancreas fails to make sufficient digestive enzymes or if the liver fails to make enough bile, you may also develop malabsorption. In addition to symptoms of malabsorption, you may experience:

  • Loose stools
  • Fatty stools that smell foul
  • Weight loss
  • Cramps and gas

You may develop vitamin deficiencies if your body cannot properly absorb fat. Since vitamins A, D, E, and K are fat-soluble, your body will not absorb these vitamins if it is not absorbing fat from your diet. You may also develop a calcium deficiency because vitamin D is necessary for the body to absorb calcium.

Malabsorption may be caused by:

  • Celiac disease
  • Crohn’s disease
  • Whipple’s disease
  • Parasitic infection
  • Bacterial overgrowth in the intestine
  • Bariatric surgery
  • HIV and AIDS

Decreased Stomach Motility

When it is functioning properly, your stomach moves to break down food and move it into the small intestine. Gastroparesis, or stomach paralysis, occurs when the normal movement of the stomach stops or slows. Symptoms of indigestion characterize this condition and may be triggered by eating high-fat or high-fiber foods or drinking carbonated beverages.

Some common causes of the condition include:

  • Diabetes
  • Infection
  • Hypothyroidism
  • Eating disorders
  • Some autoimmune conditions
  • Radiation treatment and chemotherapy
  • Upper intestinal tract surgery

If you are diagnosed with gastroparesis, your doctor will advise you on the best diet to follow to minimize your symptoms. This may include avoiding high-fat foods, chewing food well or blending food into small particles, and consuming soft or liquid food such as nutritional shakes. In serious cases, a feeding tube or other procedures may be required to treat the condition.

The Takeaway

  • Fatty food intolerance is when your body cannot digest fatty food properly. Symptoms include stomach pain and bloating.
  • The cause of this intolerance is unknown, but it may be due to hormones in the gastrointestinal tract, slower digestion, or fat malabsorption.
  • Gastroparesis can also adversely affect the digestive system.

Resources We Trust

EDITORIAL SOURCES
Everyday Health follows strict sourcing guidelines to ensure the accuracy of its content, outlined in our editorial policy. We use only trustworthy sources, including peer-reviewed studies, board-certified medical experts, patients with lived experience, and information from top institutions.
Resources
  1. Tsai B. How Much Fast Food Do We Eat in America? Centers for Disease Control and Prevention. June 26, 2025.
  2. Food Intolerance. Cleveland Clinic. August 11, 2021.
  3. Food Intolerance Versus Food Allergy. American Academy of Allergy, Asthma & Immunology. January 10, 2025.
  4. Chung BY et al. Effect of Different Cooking Methods on Histamine Levels in Selected Foods. Annals of Dermatology. October 30, 2017.
  5. Editorial Staff. Indigestion | Symptoms and Relief. FamilyDoctor.org. June 2025.
  6. Duboc H et al. The Role of Diet in Functional Dyspepsia Management. Frontiers in Psychiatry. February 5, 2020.
  7. What Causes a Gallbladder Attack? Johns Hopkins Medicine.
  8. Can You Recommend a Diet After Gallbladder Removal? Mayo Clinic. March 8, 2025.
  9. Fecal Fat. University of Rochester Medical Center.
  10. Problems With Digesting Fat After Weight-Loss Surgery. University of Rochester Medical Center.
  11. Lehrer JK. Malabsorption. MedlinePlus. June 11, 2024.
  12. Buch PS. Gastroparesis. American College of Gastroenterology. June 2021.
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Yuying Luo, MD

Medical Reviewer

Yuying Luo, MD, is an assistant professor of medicine at Mount Sinai West and Morningside in New York City. She aims to deliver evidence-based, patient-centered, and holistic care for her patients.

Her clinical and research focus includes patients with disorders of gut-brain interaction such as irritable bowel syndrome and functional dyspepsia; patients with lower gastrointestinal motility (constipation) disorders and defecatory and anorectal disorders (such as dyssynergic defecation); and women’s gastrointestinal health.

She graduated from Harvard with a bachelor's degree in molecular and cellular biology and received her MD from the NYU Grossman School of Medicine. She completed her residency in internal medicine at the Icahn School of Medicine at Mount Sinai, where she was also chief resident. She completed her gastroenterology fellowship at Mount Sinai Hospital and was also chief fellow.

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Katherine Malone

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Maureen Malone is a writer and martial artist in Tucson, Arizona. She has a black belt in Hapkido and karate and has trained in many other arts including Brazilian Jiu-Jitsu and Capoeira. She is passionate about all aspects of fitness and maintaining a healthy lifestyle.

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