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In my pediatric nutrition practice, I’ve been asked if ketogenic diets make sense for kids. Are ketogenic diets good for kids? Are they safe for kids? What do they do for kids’ health? I’ve met parents trying out ketogenic diets for themselves, with impressive results for their own health, weight loss, energy level, or fitness – why not put the whole family on board?

What is a ketogenic diet?

This means that carbohydrates are all but eliminated from the total diet that you eat. Typically – at least in modern industrialized societies – carbohydrates, starches, and sugars can make up half to two thirds of your total food intake. When switching to ketogenic eating, you will reduce that drastically, and eat proteins, fats, and oils instead, with very little of your total calorie intake coming from a carb.

For example: Even lower calorie adult diets might include anywhere from 1000 to 1200 calories daily from fruits, grains, vegetables, juices, sugars, and sweets. To go ketogenic, you would reduce that to perhaps 150 to 200 calories or even less coming from those sources, in total. Everything else you eat is going to be something that has zero or very low levels of carbohydrate.

Eggs, butter, ghee, vegetable oils, coconut oil, meat, fish, poultry, bacon or cured meats are ketogenic diet staples. High fat dairy foods and nuts are workable, but these add some carbs that you must count as well (cashew is an extra carb-y nut for example). Leafy greens are allowable as they have negligible caloric value from any macronutrient (but are great for minerals). Lastly some low starch veggies can work here and there, as long as your carb limit is not surpassed daily: Summer squash, celery, asparagus, cabbage, cucumber, green beans, and Brussels sprouts are some examples. For fruits, olives, tomatoes, and avocados may be on the list too, with limited servings allowable for berries or other fruit.

This shifts fuels for every cell in your body. Different cells have subtle differences in their capacities for what fuels they use and how, but ketogenic diets mean you’re relying mostly on ketones, instead of glucose, for fuel. We are built to use ketones as a back up fuel when starches or carbs are minimal in our diets, or during periods of fasting or starvation. We can generate ketones from fats and proteins in food when carbohydrates are absent or drastically reduced. We can also mine our own fat tissue for ketones during a fast or starvation period. Once we’ve depleted our fat reserves, we will take apart our own muscle and other tissue for a fuel source, and can turn this into ketones or a little glucose too. Some food proteins can be digested and metabolized to create blood glucose for us as well, but this is inefficient compared to making blood glucose from carbs in our diets.

Ketogenic Diets For Kids Aren’t New

Ketogenic diets aren’t new. Over a century ago, ketogenic diets were noted for their power to reduce epileptic seizures. Throughout the ensuing decades, even conventional training in neurology and dietetics included strategy on ketogenic diets for kids who have poorly controlled seizures. This tactic is still in use: Typically, if three different medication trials have failed, a neurologist may turn to a ketogenic diet strategy. Registered dietitians are trained in how to implement and monitor ketogenic diets for kids with epilepsy.

It’s not unusual for a child with epilepsy to be admitted to hospital for the transition to a ketogenic diet. It’s necessary to monitor blood chemistries and ketones during this fuel transition process, make sure stooling can continue comfortably, assure that seizure pattern responds, and establish that the new foods are tolerated. If your child has needed seizure medication, don’t try this at home. Get guidance from your provider team on whether a ketogenic diet is the right step for your child. If the answer is yes, request professional oversight with a registered dietitian experienced in pediatric neurology so you can use this diet safely and effectively.

Ketogenic diets use high amounts of fats and oils, lots of protein, and very little carbohydrate. Typically about 70% of all the food you eat on a ketogenic diet will come from fats and oils, with only about 5% coming from carbohydrates. By contrast, kids usually eat anywhere from 50-60% of their total diets as carbs, with 30-40% as fats – so this is a big switch. In children, this means eating as little as 60 calories a day from carbohydrate, sugars or starches. That’s roughly equal to one small apple.

Although using ketogenic diets for kids or even adults with epilepsy is not new, what is new is their popularity for weight loss, fitness, cancer, or autoimmune conditions like  Alzheimer’s, multiple sclerosis, or autism.

Unless there is call for it for a condition like epilepsy, or an autoimmune condition that has not responded to other measures, ketogenic diets are not ideal for children. Even for children with autism – for whom ketogenic diets have been proposed as a therapy, it’s preferable to tap other gut health and nutrition therapy measures first.

Here’s why: Ketogenic diets for kids have a cost, and can trigger unwanted side effects.

One side effect I witness often in my practice is stunting. This was noted in this study in children using ketogenic diets. The children’s progress for linear growth (that is, height or stature) slowed down after 15 months on the diet.

I’ve encountered this many times in children in my own practice whose parents placed them on ketogenic diets even inadvertently. In an effort to restrict sugars in general, some families over-reach, and the child ends up with measurable ketones in urine. After some time eating this way, a growth impairment can ensue; I have seen stunting or regression for stature occur within 4-6 months for young children eating ketogenic or near-ketogenic diets. This may be partly due to changes in bone density. Effects on bone development were closely scrutinized in this study, which found reduced bone density with ketogenic diets for kids.

Kids who come into my practice on unmonitored ketogenic diets often follow what occurred in this study, which also saw slowed growth for height and weight in children using ketogenic diets. And in this study, the number of children who fell below tenth percentile for height more than doubled while using ketogenic diet. They also had more than expected kidney stones and bone fractures. Children also may gain weight more slowly on ketogenic diets, impairing their growth pattern for both weight and height.

Slowed growth is not just a physical issue. It can have cognitive, functional and behavioral impacts too – and this another often-seen issue in my pediatric nutrition care practice. Ketogenic diets for kids may create unwanted cognitive effects, as described in this study on developing rats.

In my practice, one of the most common findings for school children with ADHD/ADD is that they are underfed – ironically, often because they have been using a stimulant medicine that suppresses appetite. Eating poorly day after day, and showing ketones in urine when we test, they disintegrate behaviorally and for focus. Their food intakes need improvement, but being in ketosis does not seem consistently helpful.

These impacts may not be a concern for adults on ketogenic diets. This very small study of only three individuals did not find changes in bone density after five years on a ketogenic diet. This study of sixty-five adults saw reduced bone density in groups using either very low carb or calorie restricted diets for weight loss, but it’s unclear if the subjects sustained ketosis or not, or if bone density dropped simply because subjects weighed less at the end of the trial.

Other effects I have encountered in children in my pediatric nutrition practice on unmonitored ketogenic diets are anxiety, inattention, mood swings, poor sleep patterns, constipation, irritable stools, and impulsivity. I’ve measured high ketones in urine in many of these cases – but the food diaries of these children, when quantified, suggest this is poorly controlled, and their metabolic state may be haphazardly switching fuels from one day to the next. This is a recipe for a disintegrating, unhappy or fatigued child who won’t grow well.

The Up-Side of Carbs

I have quantified thousands of food diaries over my years in practice for infants, toddlers, kids and teens. Without question, many kids I encounter come in with carb-heavy, low quality diets that rely too much on processed grains, sugary yogurt, juices, or starchy crackers and snacks. Not good – Carbs have been demonized, and not without cause.

But there is an up-side when eat kids as much as 50-65% of their diet from clean carbs. Kids are growing. Adults aren’t. For growing kids, carbohydrates in the diet are prime fuel. They spare protein and fat in the diet for other critical tasks – both metabolic and structural – that adults simply don’t have because they’re not growing. Protein is a lousy fuel source, requiring more steps to extract the carbon skeleton in it so a cell can use it for fuel. It’s like throwing your nice furniture in the wood stove to heat your house.

A child needs a lot more energy per pound than an adult. Depending on a child’s age or growth status, they can need as much as five times more calories per pound than an adult! This could be the same as an adult eating ten thousand calories every day, just to maintain a healthy weight. This is partly because kids’ brains use about double the amount of fuel every day compared to adults, in terms of the percentage of energy derived from the food you eat. This is true until about age four, when head growth slows down relative to the rest of the body.

Varied and healthful carb sources – whole or sprouted grains, raw fruits or vegetables, legumes, pulses, beans, root vegetables – diversify and strengthen the gut microbiome, while a ketogenic diet will reduce diversity for key protective species like Bifidobacterium and possibly other butyrate producing bacteria necessary to protect and nourish the colon wall. I too have found this to be the case in kids on low carb, quasi-ketogenic diets: I have often seen an overabundance of commensal Clostridia species plus dysbiosis for excessive Strep species with a marginal status for Bifido, Lactobacillus, or Akkermansia on stool study.

When kids eat healthy, clean carb sources with good protein and ample varied fats, they grow well, and behave, sleep, and learn well too – I’ve seen this hundreds of times. “Clean carbs” are unprocessed, no-added-sugar, whole foods. Think vegetables, legumes, and tubers – parsnip, squashes (butternut, acorn, spaghetti squash, zucchini, pattypan), asparagus, cruciferous vegetables like Brussels sprouts, broccoli, Romanesco, or cauliflower, carrot, potato or sweet potato (skins too!), greens, lentils, whole fresh organic corn on the cob, chick pea or beans, green and wax beans, arrowroot, cassava, or manioc are all carbs to have on your menu rotation. Fresh fruits too, in their original form – not as sweetened juices, yogurt blends, or sugary fruit cups. if your child is gluten free and can’t enjoy wheat, include whole grains that are gluten free like buckwheat, sprouted sorghum, or gluten free oat. Don’t overlook whole quinoa, or tigernut flour, both useful starches with prebiotic fiber and minerals in them (see these recipes for ideas on baking with tigernut flour).

Aren’t Babies Born In Ketosis? Doesn’t That Prove Ketogenic Diets Are Good For Kids?

It’s true that generally, babies are born in a mild state of ketosis. This happens because once the baby is cut off from the mother’s blood supply – once the placenta is clamped or separated – blood glucose is cut off. A number of hormonal changes occur at this moment to kick in ketones quickly, and maintain a fuel source for the baby. The baby’s brain critically needs a fuel source right away, and this is where fat-rich colostrum – mother’s first milk – comes in. This very fatty version of breast milk is able to maintain the mild ketotic state for the baby early on. Ketones are preferentially allowed into the delicate new brain over glucose as an energy source in that first month too. This is when “early milk” or colostrum has more than twice as much fat than carbs in it.

By the end of the first month, breast milk macronutrient ratios shift, so that it’s nearly 40% carbohydrate. After that early milk, we evolved to give our babies 30-40% of their calories as carbs in the first year. This lets the baby’s head grow quickly while the rest of the body can gain weight and get longer too. It also lets the baby’s gut microbiome diversify, which reduces risk of allergic conditions later on, improves immune function, and assists with availability and absorption of vitamins and minerals.

For infants or kids with seizure disorders, ketogenic diets can be miraculous. They change gut bacteria, even for infants, but for a refractory condition like epilepsy, this can be a worthy trade off. Follow your care team’s advice if this is your situation.

Ketosis isn’t always good Here are warning signs that your child is in a dangerous state of ketosis:

Ketogenic diets that are poorly monitored can be dangerous. I don’t recommend using them for children except for specific conditions and with medical supervision. In any case, here are signs of hyperketosis – . If you see those signs, call your doctor right away or go to your nearest emergency room.

  • Rapid, panting breathing
  • Rapid heart rate
  • Facial flushing
  • Irritability
  • Vomiting
  • Unusual lethargy, fainting, dizziness
  • Fruit or acetone breath
  • Clammy skin
  • Refusal to feed or eat, or difficulty eating

Need help figuring out what nutrition is best for your kids? Contact me here or place a comment below – thanks for stopping by!