Foods to Eat and Foods to Avoid Before a PET Scan
Medical ProceduresImaging

Foods to Eat and Foods to Avoid Before a PET Scan

Foods to Eat and Foods to Avoid Before a PET Scan
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Updated on November 5, 2025
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A positron emission tomography (PET) scan is a diagnostic tool that examines body tissue functioning, such as blood flow, oxygen use, and sugar metabolism, to help doctors diagnose and treat disease.

To conduct a PET scan, a healthcare provider injects a small amount of radioactive glucose into a patient’s vein, which allows extremely small cancerous tumors and changes in the heart and brain to show up on the scan.

It's important to follow the specific pre-PET scan diet your doctor recommends to allow the proper distribution of glucose throughout your body.

Types of PET Scans

There are a few types of PET scans:

A fluorodeoxyglucose (FDG) PET scan is used for heart conditions and the detection of tumors, brain disorders, or infections.

 FDG is the most common radiotracer used for PET scan injections.

A PET-CT scan is a combined PET and computerized tomography (CT) scan. While PET scans show how tissues and organs in the body are working, CT scans generate 3D images of structures in the body.

Meanwhile, a myocardial perfusion PET stress test, also known as a rubidium or adenosine PET, is used to evaluate blood flow through the coronary arteries to the heart muscle.

Different types of PET scans may require different dietary preparations, so check with your doctor to confirm which type you're scheduled to receive.

Foods to Eat Before a PET Scan

In the 24 hours before a PET or PET-CT scan, it’s recommended that you drink extra fluids, preferably water. Foods to eat beforehand include:

  • Protein-rich foods, such as beef, chicken, eggs, ham, pork, raw nuts, turkey, tofu, and unsweetened peanut butter
  • Vegetables low in carbohydrates, such as green beans, broccoli, celery, lettuce, spinach, and zucchini
  • Dairy products low in carbohydrates, such as butter and hard cheeses
  • Condiments low in carbohydrates, such as oil and vinegar

Foods to Avoid Before a PET Scan

For up to 24 hours before a PET or PET-CT scan, avoid sugar, sugary foods, high-carbohydrate foods, and most processed foods. Foods to skip the day before include:

  • Grains, including bread and breaded foods, cereals, crackers, oats, pasta, and rice
  • Starchy vegetables, such as corn, peas, and potatoes
  • Fruits and fruit juices
  • Dairy products higher in carbohydrates, like yogurt and ice cream
  • High-carbohydrate condiments, such as jams, gravies, and most salad dressings
  • High-carbohydrate snack foods, like chips and pretzels
  • Candy
  • Beverages that contain caffeine

  • Alcohol
In addition to avoiding these foods and beverages for the 24 hours before your scan, it’s important to avoid any strenuous activity, such as exercising or heavy lifting, for 48 hours before the scan.

For the eight hours preceding your scan, don’t chew gum or eat or drink anything except water. Hydration is key for optimal test results.

Foods to Avoid Before a Myocardial Perfusion PET Stress Test

If you’re undergoing a myocardial perfusion PET stress test, don’t eat or drink caffeinated products, such as coffee, tea, soda, or chocolate, for 24 hours prior to your appointment. It’s also best to avoid decaffeinated versions of these foods and drinks, because they still contain a small amount of caffeine.

If you're taking beta-blocker or calcium channel blocker medications, consult your doctor well before your scan to discuss when to stop taking these medications.

For the three hours prior to your scan, don’t eat anything or drink anything except water.

PET Scan Preparation and Diabetes

People who have diabetes should consult their doctor about how to prepare for a PET scan at least two weeks before the scan, as changing their diet may also require changing their diabetes medication regimen.

If your blood sugar level is outside a particular range on the morning of your scan, it may need to be rescheduled.

The Takeaway

  • For 24 hours before a PET or PET-CT scan, drink extra fluids and consume a protein-rich, low-carbohydrate diet, including foods like meat, eggs, raw nuts, low-carb vegetables, butter, and hard cheeses.
  • During this 24-hour period, it’s crucial to avoid all sugar, high-carbohydrate foods, alcohol, and caffeine to prevent interference with the radioactive glucose tracer.
  • In addition to dietary restrictions, avoid strenuous activity for 48 hours before a myocardial perfusion PET stress test.
  • You should fast, consuming nothing but water, for the eight hours before the procedure.
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. PET Scan. Cleveland Clinic. October 19, 2022.
  2. Ashraf MA et al. Fludeoxyglucose. StatPearls. August 28, 2023.
  3. PET/CT. Radiology Info.
  4. Myocardial Perfusion PET Stress Test. Cedars-Sinai.
  5. PET/CT Scan Preparation Guidelines. Florida Cancer Specialists and Research Institute.
  6. FDG-PET Scan. Cedars-Sinai.
  7. Before Your PET Scan. Stanford Medicine Health Care.
  8. PET/CT FDG Scan for Patients With Diabetes. UW Medicine.
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Simran Malhotra, MD

Medical Reviewer
Member of American College of Lifestyle Medicine
Simran Malhotra, MD, DipABLM, CHWC, is a triple board-certified physician in internal medicine, hospice and palliative care, and lifestyle medicine, as well as a certified health and wellness coach. She is currently practicing part time as an inpatient palliative care physician at Medstar Health after serving as the palliative care medical director at Franklin Square Medical Center in Baltimore for a little over four years.

Dr. Malhotra completed her internal medicine residency at Medstar Franklin Square Medical Center, where she also served as chief resident in 2015. She completed her fellowship in hospice and palliative medicine at Johns Hopkins Hospital in 2016. She was named Top Doc in Palliative Medicine in 2019 and 2020 by Baltimore Magazine.

On a personal note, she is a BRCA1 previvor with a strong family history of breast and female reproductive cancers, and underwent a risk-reducing bilateral mastectomy and total hysterectomy in 2020 at 32 years old. After learning about her own genetic risk of cancer, and grounded in her professional experiences in palliative care, she founded Wellness By LifestyleMD, a platform where she works with and educates women at high risk for cancer with or without genetic mutations on the powerful impact that positive lifestyle changes can have on their quality of life and even longevity.

In addition to being a diplomate of the American College of Lifestyle Medicine, she completed the T. Colin Campbell plant-based nutrition certification in 2019, the CHEF culinary coaching certification in 2020, and the WellCoaches health and wellness coaching certification in 2022. She is a member of the ACLM women’s health member interest group and serves as the co-chair of the breast cancer subcommittee.

Malhotra has been featured on several blogs and podcasts, where she has shared her unique perspectives and experiences from palliative care as well as from being a genetic mutation carrier who is passionate about using lifestyle as medicine.
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Gord Kerr

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Gordon Kerr is a retired nutrition professional with more than 15 years of experience in the healthcare industry. He holds a diploma in Food and Nutritional Science from the Canadian School of Natural Nutrition (CSNN) in Vancouver and currently resides in British Columbia.

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