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Key Point

Being on the ketogenic diet might cause a number of side effects which we will monitor for during your child’s hospital stay. Parents and caregivers will need to continue to watch for these possible changes once you return home.


When Starting the Diet

  • Low blood sugar - We will check blood sugars frequently when your child starts this diet. This will help us treat low levels, if needed.
  • Nausea/vomiting - This might occur if the diet is started too fast. The child might need to slowly transition to the ketogenic diet. Diet ratios are started low to allow your child to gradually get used to the diet.
  • Lethargy - Your child might be lethargic (tired and worn out) during the first couple days of the diet. This will improve.

While on the Diet

  • Dehydration - This might happen if your child is not taking in enough fluids. A urine specific gravity test can check for dehydration. We will show you how to do this test at home.
  • Poor linear growth - Children on this diet might not grow at the same rate as those not on the diet. Checking a child’s intake of calories, proteins, vitamins and minerals (such as zinc, selenium and carnitine) might prevent poor growth. We do a bone-age X-ray when a child starts the diet, and then again every six months. This monitors your child’s bone growth. Frequently checking a child’s length or height and weight with a growth chart also helps.
  • Constipation - Any change in a child’s diet can potentially cause constipation (not having a bowel movement in two days). If your child is constipated, it can be treated by:
    • Drinking enough fluids
    • Eating vegetables, such as lettuce and avocado
    • Using polyethylene glycol and/or glycerin or bisacodyl suppository
  • Bruising - Some children notice they bruise more easily. We will evaluate lab tests to notice if any changes might be associated with bruising. Also, some medicines can cause this to happen. We will also check your child’s intake of calories, proteins, vitamins and minerals.
  • Breath odor - Change in breath odor might occur because of the release of ketones. The odor might smell like overripe fruit.
  • Kidney stones - The child’s diet must contain enough liquid to prevent kidney stones. An ultrasound of your child’s kidneys (renal ultrasound) will be done when the diet is started and then will be repeated every three to six months. Children will also have their urine checked for any abnormalities every three months. You will do urine specific gravity tests and check for blood on a weekly basis. If any blood is found in the urine, contact Telehealth Nursing at 651-229-3890.
  • Thinning of bones (osteoporosis) - Patients with immobility, acidosis and chronic use of antiepileptic drugs are at high risk for bone thinning. A diet with adequate calcium, vitamin D, and phosphorus can help prevent this complication. Dietary supplements might be needed. Osteoporosis can also be corrected or prevented by increasing weightbearing activities such as using a stander or walking with or without a walker.
  • Hyperlipidemia (increased lipids in the bloodstream) - Your child’s medical history will be reviewed for any indication of hyperlipidemia. All children’s lipid levels are checked when they start the diet and then again every three months. We expect an increase in lipid levels, but a certain amount of increase might require changes in treatment. For example, if necessary, we can modify the amount and type of fat in a child’s diet. 
  • Conduction (abnormal heart rhythm) - While this is a very rare complication, there have been reports of a prolonged abnormal heart rhythm in some patients on the ketogenic diet. An electrocardiogram is done when your child starts the diet to establish a baseline. This is then repeated after the child has been on the diet for a month. If the electrocardiogram is normal, the test will be repeated yearly. If it is abnormal, we might do further testing. Monitoring and maintaining carnitine and selenium levels can help prevent these abnormalities.

For More Information

If you have any questions about these side effects or complications, refer to your “Ketogenic Diet” book by John Mark Freeman or call Telehealth Nursing at 651-229-3890.

This information is for educational purposes only. It is not intended to replace the advice of your health care providers. If you have any questions, talk with your doctor or others on your health care team. If you are a Gillette patient with urgent questions or concerns, please contact Telehealth Nursing at 651-229-3890.