Little Kids

Is a keto diet safe for kids?

The keto diet is one of the biggest weight loss trends, and now parents are putting their kids on keto too. Experts explain why this low-carb, high-fat diet is a bad idea for kids.

Is a keto diet safe for kids?

Photo: iStockphoto

The keto diet is one of the biggest diet trends—thanks in part to celebrity proponents like Halle Berry, Gwyneth Paltrow, LeBron James, and Kourtney Kardashian. High in fat and extremely low in carbs, the diet promises rapid weight loss, improved mental acuity, and heart health.

While it’s not surprising to see adults going on fad diets—especially to conquer new year’s resolutions—some parents are turning the keto diet into a family affair. There are cookbooks, blogs, and even Facebook pages devoted to raising what the industry calls “keto kids.” But should children be put on such a restrictive diet?

What is the keto diet?

The ketogenic diet (keto for short) is designed to drive the body into ketosis, a metabolic state where fat is burned for energy instead of carbs. It requires you to eat foods that are high in fat, while consuming next to no carbohydrates. When carbohydrates are in short supply, the liver converts fat into molecules called ketones, which are used as an alternative energy source.


What can you eat on the keto diet?

Because keto is so restrictive, it’s more about what you can’t eat. Grains, sugar, fruit, and starchy vegetables are basically off the table. On keto, only 5 to 10 percent of your diet can come from carbohydrates. For a 1,500-calorie diet—which is the typical caloric intake for kids ages four to 12—that’s about 20 to 40 grams. (A medium banana has 27 grams.)

Unlike other low-carb diets like the Paleo Diet or the Atkins Diet, the keto diet also limits protein, which can only make up 20 percent of your calories—any excess is converted to glucose, kicking you out of ketosis.

That leaves you with fat, fat, and more fat—making up a whopping 60 to 80 percent of your diet. Think fatty meat, cheese, eggs, nuts, oils, and avocado. And the diet doesn’t distinguish between good and bad fat. This means bacon for breakfast, lunch and dinner!

Is it safe to put kids on the keto diet?

In short, no. In fact, the keto diet wasn’t intended for weight loss—it was developed back in the 1920s to control seizures in epileptic children.


“In my opinion it is not safe without medical supervision,” says Helen Lowe, who is a dietitian with the Ketogenic Diet Program at SickKids. She treats children with epilepsy using a ketogenic diet—but only after they have been thoroughly assessed by the medical team.

“We review all the potential side effects, and we monitor them very closely,” she says.

Patients must undergo regular testing: bloodwork, ultrasounds, and other testing to monitor their growth and nutrient intake. While the exact mechanism that makes it work isn't yet fully understood,  Lowe says that the current research shows a strong correlation between being in good ketosis and seizure control.

However, between the food restrictions, the medical surveillance and the risk of malnutrition, the keto diet is no child’s play. That’s why the team typically treats children who have already tried two or more anti-epileptic medications.

“We would not recommend putting children on a ketogenic diet if it wasn’t medically indicated,” says Lowe.


Dan Flanders, the owner and executive director of KinderCare Pediatrics, says he’s not aware of any data on the long-term impacts of ketosis on “relatively healthy” children.

“And this is why there is reason for concern,” he says. “Children are going on ketogenic diets without medical supervision and without anyone knowing whether what they are doing is safe or effective.”

Are there side effects with the keto diet?

Because the keto diet restricts many wholesome fruits, vegetables, and grains, it’s missing a lot of nutrients. Lowe says the diet is particularly low in bone health minerals like calcium, magnesium, and phosphorus. She also sees a reduction in iron, selenium, zinc and B vitamins in her patients. Nutrient deficiency can cause problems like poor bone health, slowed growth, kidney stones, vomiting, and reflux. Consequently, her patients take a myriad of supplements.

Another key nutrient missing from the keto diet is fibre, which can’t be supplemented because it’s a carbohydrate. That’s a big problem, since fibre is essential for healthy bowel function and feeds beneficial bacteria in the gut. Not surprisingly, constipation is a common side effect of the keto diet.

One of the most talked about side effects of keto is the so-called keto flu. People who are adjusting to the diet say they experience a range of symptoms, including headaches, foggy brain, fatigue, irritability, and difficulty sleeping. While the condition isn’t understood or recognized by medicine, it’s certainly not something you’d want to inflict on your kids.


Besides the physical side effects, dieting can also have psychological impacts on children.

Dietitian Rebecca Bergel says the keto diet could create negative associations with food, causing a child to think certain foods like fruit and vegetables are unhealthy—even if they offer important nutrients, fibre, and energy required for optimal growth and development.

She adds that it isn’t fair or realistic to expect children to forego treats like birthday cake or occasions like pizza day. Restricting any type of food will simply cause kids to overindulge when given the chance. That’s why the keto diet simply isn’t sustainable in the long term.

“I would never put them on any type of very stringent meal plan,” she says.

How should parents on the keto diet feed their kids?

Bergel doesn’t recommend the keto diet for anyone—adults included. Instead of cutting carbs, she encourages low-glycemic carbohydrates from whole grains and vegetables. These are broken down more slowly, minimizing spikes in blood sugar and insulin levels.


She says every meal should include protein, carbohydrates, and plenty of vegetables.

Lowe agrees. She recommends that both children and adults follow Canada’s Food Guide.

“Eating a variety of foods allows you to make sure that you are getting the micro nutrients that you require.”

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