Sick Day Instructions for Children on the Ketogenic Diet

Illnesses are part of childhood and can be difficult to manage when your child is eating the high fat, low carbohydrate ketogenic diet. Do not hesitate to reach out to the ketogenic diet team when your child is sick if you have problems, we are here to help. The instructions below will help guide your family when your child is sick.

Patient instructions:

What if my child cannot finish the meal?

It is not unusual if a child does not complete a meal in the first two weeks of treatment. By the first follow-up appointment, most children are eating 100% of their meals without difficulty. For children who are in the maintenance phase of the ketogenic diet, refusing to finish the meals may happen if they are tired of their food choices. It can also happen when they are getting sick, constipated, or having medical issues, like reflux.

It is fine to only eat a portion of the ketogenic meal during an illness. Your child will remain in ketosis even when they are not eating 100% of their calories.

What if my child tolerates the ketogenic diet fluids but cannot eat solid foods?

You can make a liquid ketogenic meal (“smoothie”) with ingredients such as heavy cream, oil, juice, yogurt, or milk (whole milk, unsweetened soy milk, or milk alternatives). Your child can sip on the smoothie throughout the day.

What if my child has an upset stomach or GI illness and is unable to tolerate any of the ketogenic diet, including the smoothie or formula?

Let the stomach rest for 24 hours. A high-fat diet is difficult to handle with vomiting or diarrhea. Do not advance to solid food until the vomiting stops. Encourage ketogenic diet fluids: water, Kool-Aid®, decaffeinated tea, 12 ounces of diet, caffeine-free soda, or diluted formula. Sometimes flat diet soda helps settle the stomach. When your child is unable to eat anything or tolerate the smoothie, one carbohydrate exchange (such as 8.5 gm/mL apple juice or 40 gm/mL Pedialyte) should be given every three hours, along with the keto diet fluids.

Should I encourage fluids on sick days?

Yes, fluids are important to the body, especially when your child has a fever. Maintaining adequate fluids is especially important when children are sick. Refer to your child’s diet plan for their minimum daily fluid needs.

When my child can eat, should I begin the full ketogenic diet?

Reintroduce solid food slowly. You can start by offering the carbohydrate or protein portion of the meals without any fat or heavy cream. As your child improves, protein, fat and heavy cream can be gradually added back into the diet.

If you are advancing the diet and vomiting or diarrhea worsens, please go back to the ketogenic diet beverages, and try to give solid foods later.

What if my child is on formula or tube feedings?

On sick days, diluted formula may be easier to tolerate. You can prepare half-strength formula by mixing equal amounts of water and ketogenic formula. For example, if your child normally takes 6oz of formula at a feeding, mix 3 ounces of formula with 3 ounces of water to create a 6-ounce, half-strength formula. For children with tube feedings, slowing down the rate is highly recommended.

If your child is not tolerating half strength formula, you can replace the formula with water and give 1 carbohydrate exchange every 3-4 hours.

What are some signs of dehydration?

• Decreased urination

• Dry lips

• Dry mouth

• No tears

• Dark circles under the eyes

• Skin that stays up when gently pinched

• Increased heart rate

When should I be concerned about dehydration?

If your child has persistent vomiting or diarrhea, they are at a higher risk of becoming dehydrated and you should contact your primary care provider. Usually vomiting and diarrhea are not related to the diet itself. However, alert your keto team if your child has these symptoms. Especially if there is abdominal pain associated with vomiting. If your local provider is concerned about dehydration, your child may need dextrose-free and glucose-free intravenous (IV) fluids.

Should I monitor the blood sugar during sick days? How do I treat a low blood sugar?

When your child is sick, check their blood sugar two times per day.

• Morning (fasting; before the first meal/feeding of the day and medications)

• Late evening (before the last meal/feeding of the day)

Remember to treat a blood sugar reading of 45 mg/dl or lower and recheck it in 30 minutes to be sure it improves. Repeat this procedure until the blood sugar is above 50 mg/dl.

To treat a blood sugar of 45 mg/dl or lower, give one of the following beverages:

• 8.5 gm/mL apple juice

• 9.0 gm/mL orange juice

• 40 gm/mL Pedialyte® (any flavor or unflavored)

• 33 gm/mL Enfalyte® (any flavor or unflavored)

• 16 gm/mL Gatorade® (any flavor)

If your child is in the hospital and unable or not permitted to take anything by mouth, the healthcare team can treat a low blood sugar with an intravenous infusion of 20 ml of D5W (one carbohydrate exchange).

Can I use Tylenol® (acetaminophen) and Motrin® (ibuprofen) for fever or pain?

Yes, but please refer to the medication list given to you during your admission.

What do I do if my child gets into something that is not on the ketogenic diet?

If you are notified within 24 hours, give 1 full fat exchange (oil, butter, mayonnaise). If you find out and it has been more than 24 hours, there is nothing that needs to be done.

Reviewed June 2024 by Christina Bergqvist MD