When you turn 45, or earlier if you're high risk, your doctor may want you to undergo an inconvenient procedure — a colonoscopy. The prep is what's inconvenient, though, and starting 72 to 48 hours before a colonoscopy, you'll have to change your diet. It won't be fun, but it will be worth it.
You should stop eating nuts and other high-fiber foods three days before a colonoscopy to clear your bowels. If you continue to eat these types of foods before the procedure, your doctor may not be able to fully check your colon and rectal area for cancerous tumors or polyps.
Why a Colonoscopy?
Colon and rectal cancers, known as colorectal cancers, are the third most common type of cancer in men and women and the second leading cause of cancer-related deaths in the U.S., says Harvard Health Publishing. Taken together, colorectal cancers are the leading cause of cancer death for men and women, according to the American Cancer Society (ACS).
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When colon or rectal cancer is found in the early stages, the survival rate is about 90 percent, the ACS says. But about one in three people who should get tested don't. Most people need to get tested once every 10 years, although higher-risk people need to get tested more often. You probably won't like the prep, but most experts, like those at Harvard Health Publishing, say it's worth the inconvenience.
A colonoscopy can spot small tumors on the colon or rectal area while they are treatable and before they can spread to other parts of the body, according to the ACS. A colonoscopy can also detect and remove polyps, which are small growths that can grow into tumors and become cancerous.
In a colonoscopy procedure, a small, flexible tube with a light and video camera is inserted into your rectum and your colon. The tube is wide enough to accommodate special instruments that can biopsy or remove any polyps or suspicious-looking areas.
Your doctor wants to see the entire inner lining of your colon and rectum, so that's why you need to cut out most solid foods and certain liquids before the test.
48 Hours Before a Colonoscopy
At this time, you will have already started your prep. You need to give up nuts and other high-fiber foods 72 hours before your colonoscopy procedure. Your doctor will advise you, but if you want more information, Kaiser Permanente has a handy chart of foods to avoid before a colonoscopy procedure.
No nuts or seeds, including peanuts, walnuts and almonds, should be eaten starting 72 hours, or three days, before your procedure. Nor should you eat chunky peanut butter or almond butter. You can continue to eat creamy peanut butter or almond butter until the day before your procedure.
Three days before, you will also have to give up many vegetables like corn, potatoes, tomatoes, squash, peas and Brussels sprouts. You can eat potatoes without skin and cucumbers without peel. You can also eat strained soups but no chunky soups or fruit or vegetable juice with pulp. Stick to t helow-fiber foods in the Kaiser Permanente list until the day before your colonoscopy.
The Day Before
With your colonoscopy scheduled for the next day, you'll want to consume a liquid diet. That means no more creamy peanut butter or creamy almond butter or any other low-fiber food that's not on the clear liquid list from your doctor or Kaiser Permanente.
Clear broth, tea and coffee with no milk, cream or other lightener; light-colored sodas and sports drinks; gelatin that is not red or purple, frozen ice pops with no fruit or cream and no red or purple dye. You will also start your bowel prep the afternoon or evening before your procedure.
Your doctor will give you specific instructions because they vary a bit, according to Harvard Health Publishing. You will drink a liquid that will encourage your bowels to clear themselves out. You'll need to be near a bathroom so you can make frequent trips. If possible, it's best to be at home for this part of the prep.
If you have followed the guidelines and the instructions your doctor gave you, you will not have a "Oh, I ate nuts before a colonoscopy" moment. Instead, you will be discharged and will soon be able to eat a normal diet again.
- Harvard Health Publishing: "Preparing for a Colonoscopy"
- Kaiser Permanente: "Low-Fiber Diet for Colonoscopy Preparation"
- Kaiser Permanente: "Clear-Liquid Diet for Colonoscopy Preparation"
- American Cancer Society: "Colorectal Cancer Screening Tests"
- American Cancer Society: "Can Colorectal Polyps and Cancer Be Found Early?"
- American Cancer Society: "American Cancer Society Guideline for Colorectal Cancer Screening"