Why should greasy foods be avoided before a colonoscopy?

Mar 28, 2025 Source: Cainiu Health

Dr. Yang Ziqi

Introduction

Under normal circumstances, the reasons for avoiding greasy foods before a colonoscopy include preventing impaired bowel cleansing, interference with the viewing field, increased difficulty during the examination, induction of gastrointestinal discomfort, and influence on the examination results. It is important to follow the doctor's instructions and adequately prepare the bowel to ensure there is no food residue or fecal matter, thereby providing optimal visual conditions for the colonoscopy.

Generally, there are several reasons why fatty foods should be avoided before a colonoscopy, including affecting bowel cleansing, interfering with the field of view, increasing the difficulty of the examination, causing gastrointestinal discomfort, and influencing the accuracy of the results. The specific details are as follows:

1. Affecting Bowel Cleansing

Fatty foods contain high levels of fat and oils, which are difficult to digest and absorb quickly within the intestines. Consuming fatty foods before a colonoscopy may leave fat and oils remaining in the intestine, forming a greasy layer that affects the effectiveness of bowel cleansing.

2. Interfering with the Field of View

Residual oils in the intestine can adhere to the intestinal mucosa, forming a hazy barrier. During colonoscopy, this oily layer may interfere with the doctor's view, making it difficult to clearly observe the details of the intestinal mucosa and affecting the accuracy of the examination.

3. Increasing the Difficulty of the Examination

Residual fatty foods in the intestine may lead to increased food residue and fecal matter, making bowel preparation more challenging. This increases the difficulty of performing the colonoscopy, prolongs the examination time, and may even require multiple flushes and aspirations to ensure a clear field of view.

4. Causing Gastrointestinal Discomfort

Fatty foods are difficult to digest and may cause slowed gastrointestinal motility, leading to discomfort such as bloating and abdominal pain. These symptoms not only affect patient comfort but may also interfere with the smooth progress of the colonoscopy.

5. Affecting the Accuracy of the Results

Residual fatty foods in the intestine may obscure lesions or abnormalities on the intestinal mucosa, leading to missed or incorrect diagnoses. For example, intestinal polyps and inflammatory lesions may be difficult to detect due to interference from fatty foods.

To ensure the smooth progress and accurate results of a colonoscopy, patients should avoid consuming fatty foods before the procedure. Additionally, it is important to follow the doctor's instructions and adequately prepare the bowel to ensure there is no residual food or fecal matter, thus providing optimal visual conditions for the colonoscopy.

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What are the efficacy and side effects of phenolphthalein tablets?

The functions of phenolphthalein tablets include treating constipation, cleansing the intestines and removing toxins, promoting digestion, relieving intestinal gas accumulation, preparing for colonoscopy, etc. Side effects include intestinal dysfunction, electrolyte imbalance, allergic reactions, intestinal melanosis, induced arrhythmia, etc. It is recommended to take the medication as directed by a physician. When experiencing constipation, do not blindly self-administer phenolphthalein tablets; instead, first attempt to improve the condition by adjusting dietary habits and other methods.