Keto Isn't Healthy for Everyone

This article contains discussion of eating disorders and treatment. Read at your own discretion.

Diet culture is, well, everywhere. Whether it be as overt as weight-loss supplements and detox teas or subtly disguised as a “healthy eating program” (looking at you, Noom), the societal pressure to lose weight is ubiquitous. At the end of the day, descriptions of what to eat and when to eat it all over the internet – especially on social media – and proponents of the ketogenic diet (sometimes called keto) offer a step-by-step guide on what to exclude. Spoiler alert: it’s a lot.

Ultimately, keto isn’t meant for everyone, and can cause more harm than good. It may seem like a quick ticket to weight loss, but its risks for mental and physical health far outweigh the “benefits.”

So...what is the keto diet?

The ketogenic diet was first introduced as a therapeutic diet for pediatric epilepsy in 1921 and was widely used until the introduction of anti-epileptic agents a decade later. A true ketogenic diet is rich in proteins and fats, and low in carbohydrates; it typically includes plenty of meats, eggs, sausages, cheeses, fish, nuts, butter, oils, seeds, and fibrous vegetables. It excludes grains (such as bread, oatmeal, rice, and quinoa), starchy vegetables (such as corn), potatoes, beans, pasta, and fruit.

The resurgence of the ketogenic diet as a rapid weight loss formula is a relatively new concept. The idea of a low-carb diet gained popularity in the early 2000s with the Atkins diet bringing keto to the general public. It’s gained traction ever since due to its face-value success for people aiming to lose weight.

"The keto diet is primarily used to help reduce the frequency of epileptic seizures in children,” said Kathy McManus, director of the Department of Nutrition at Harvard-affiliated Brigham and Women's Hospital. “While it also has been tried for weight loss, only short-term results have been studied, and the results have been mixed. We don't know if it works in the long term, nor whether it's safe."

Eating in accordance with the ketogenic diet causes the body to release ketones — chemicals made in the liver — into the bloodstream. When there isn’t enough energy from carbohydrates, ketones replace blood sugar as the primary fuel for muscles and tissues. However, the “success” of the keto diet relies on the restriction of carbs. In the absence of circulating blood sugar from food, our bodies enter a state of ketosis, or breaking down stored fat into molecules called ketone bodies.

A ketogenic diet restricts carbohydrate intake to less than 25 to 50 grams per day. Depending on your age, sex, activity level, and overall health, your carbohydrate requirements will vary. According to the Mayo Clinic, 45 to 65% of your daily calories should come from carbohydrates. Ketogenic diets, though, typically recommend that a mere 5% of calories come from carbohydrates, along with 75% from fat and 20% from protein.

“To make up for the glucose your body isn't getting through your diet, your liver turns to degradation of the body's fats,” said Dr. Daniel B. Nichols, a microbiologist and professor at Seton Hall University. “Since your body is breaking down more fats, if done correctly and under medical supervision, the diet can lead to weight loss since you need to make up the energy that you are not getting from carbohydrates.”

The downsides of keto:

Our bodies aren’t made for constant ketosis, though. Because it is so restrictive, the keto diet is also extremely difficult to follow over the long run — especially since carbohydrates normally account for at least 50% of the typical American diet. Although the keto diet may result in weight loss, it isn’t necessarily a great option for overall health.

One of the main criticisms of this diet is that many people tend to eat too much protein and poor-quality fats from processed foods, with very few fruits and vegetables. A diet rich in vegetables and fruits can lower blood pressure, reduce the risk of heart disease and stroke, prevent some types of cancer, lower risk of eye and digestive problems, and have a positive effect upon blood sugar, according to the T.H. Chan School of Public Health at Harvard University.

“A ketogenic diet could be an interesting alternative to treat certain conditions and may accelerate weight loss,” wrote Marcelo Campos, a primary care doctor at Harvard Vanguard, in the Harvard Health blog. “But it is hard to follow, and it can be heavy on red meat and other fatty, processed, and salty foods that are notoriously unhealthy.”

Additionally, weight loss and side effects of the ketogenic diet aren’t as glamorous as Instagram may lead you to believe. It’s common to experience fatigue during exercise, poor mental energy, increased hunger, sleep disturbance, muscle cramps, constipation, nausea, and stomach discomfort. And a reliance on ketones for energy may cause episodes of hypoglycemia, which is a dangerous drop in blood sugar.

“The keto diet, while it may be trendy, isn’t a great option for the majority of the population,” said Colleen Christensen — a registered dietitian nutritionist and founder of non-diet membership community, The SociEATy — in an interview with Spoon University. “The keto diet can be very harmful for so many reasons. The biggest reason beyond making you feel like crap because your body is running off of fumes (carbs are our preferred energy source!) is that it can cause nutrient deficiencies.”

While the short-term impacts of the keto diet are many and well-studied, long-term data on keto diets and cardiovascular, cancer, and other chronic disease risks are currently lacking.

“Unfortunately, it is false advertising as the public is rarely shown the long term outcomes and impact,” said Allison Chase, a licensed psychologist and Regional Clinical Director of Eating Recovery Center in Texas. “Any time dietary restriction of any food group occurs, it sets one up for unhealthy food behaviors and can lead to negative emotional functioning as well.”

How diets like keto can perpetuate disordered eating:

Despite the negative side effects, the keto diet remains popular because it’s often advertised by nutrition and fitness influencers as a “quick fix” for weight loss and optimal health, and individuals tend to report some quick weight loss. This weight loss, though, isn’t long-lasting. Reducing your energy intake too much and placing yourself in "starvation mode" can potentially slow your metabolism in the future.

"Eating a restrictive diet, no matter what the plan, is difficult to sustain,” McManus, the nutrition director at Brigham and Women's Hospital, said. “Once you resume a normal diet, the weight will likely return.”

Restricting food can quickly become a slippery slope toward disordered eating, several medical professionals warn. Restriction can also sometimes lead to anxiety surrounding food and obsessions with calorie counting; disordered behaviors such as skipping meals and ignoring hunger cues; as well as concern about overeating and compensatory behaviors such as eliminating other food groups.

“Diet culture creates an unhealthy pattern of behavior and unrealistic beliefs related to goals and outcomes, all of which can increase anxiety and negative mood symptoms and contribute to disordered eating,” Chase said.

Additionally, mental health can be impacted, especially when the goal of dieting may include altering one’s body shape. According to The National Eating Disorders Association, 35% of dieting becomes obsessive, while 20 to 25% of those diets turn into eating disorders. In addition to leading to more commonly known eating disorders such as Anorexia Nervosa, Bulimia, and Binge Eating Disorder, dieting has also been linked to symptoms of depression and Body Dysmorphic Disorder.

“The psychological aspect of the diet is huge,” Christensen, the SociEATy founder and nutritionist, said. “Dieting can impact one's social life as well as increase food related stress, cortisol levels, and anxiety which is not great for our health or wellbeing.”

Christensen warns that dieters of any type are drastically increasing their likelihood of binge eating when they restrict. Studies have shown that binge eating can lead to weight cycling — or your weight going up and down — which is linked to negative health effects. In fact, dieting and subsequent weight fluctuations have been linked to dangerous health consequences, including obesity, disordered eating behavior and other psychological disorders, cancer, Type 2 Diabetes, and Hypertension, according to the International Journal of Obesity.

Moreover, it’s important to note that a thin body does not necessarily equal a healthy body, which Christensen says is one of society’s biggest misconceptions about weight and health.

“The idea that we have 100% control over our weights is false,” Christensen said. “Our weights are determined by genetics, our environment and lifestyle factors.”

Of course, there may be diets that are better suited for an individual’s nutritional needs, and it’s important to consult a physician or nutritionist before deciding when and how to pursue any diet.

“Everyone is different metabolically,” says Dr. Li. “One diet would not work for everyone.”

If you or someone you know is struggling with an eating disorder, please contact a care provider or the National Eating Disorder Helpline at 800-931-2237 or through their website.