Is the keto diet safe?

Is the Keto diet safe? A dietitian’s perspective


The Keto diet is everywhere these days. We’re constantly hearing testimonials from friends, coworkers and/or neighbors of how much weight they lost on the keto diet. There are also the celebrities who swear by it, as well as the social media influencers who post picture after picture of their “amazing keto diet results”. And let’s not even get into the thousands of recipes you can find all over Pinterest (I love you, Pinterest!). But how exactly does the keto diet work? Are the results from following it realistic? And most importantly, is the keto diet safe? Keep reading for some fad free, evidence based advice related to this topic.

is the keto diet safe?
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What is the keto diet and how does it work?

I remember that the first time I heard about the ketogenic diet (better known as the “keto diet”) was in college. I was in a Clinical Nutrition class during my Bachelor’s degree in Nutrition and Dietetics . The professor was talking about how doctors in the 1920s would treat epilepsy in children with an extremely high fat diet. Something I never forgot is how she told us that the patients were fed butter balls to increase the amount of fat in their diet. It seemed that the high-fat diet helped them to control seizures by simulating a fasting state (we’ll get into more on that later).

After that class, every time I saw those little balls of butter that they serve in hotels and restaurants, fleeting black and white images of hospitals came into my mind: children in hospital gowns and sleeping caps being served butter balls with their meal trays (sorry, I have a crazy imagination!). I never thought that, years later, a type of nutritional therapy for a neurological condition would become the latest diet du jour.

What is ketosis and how does it help you lose weight?

The name Keto comes from the word ketogenic. I’ll explain. The body normally uses carbohydrates, broken down into glucose, as its main source of energy. Actually, glucose is the brain’s preferred energy source. A ketogenic state occurs when the body uses fat instead of carbohydrates as energy. This happens under a state of fasting or starvation (since there is no carbohydrate intake). When the body begins to burn fat as a source of energy, substances called ketones are produced. Hence, the name of the diet. Under a ketogenic state, the body uses the ketones as energy instead of glucose.

Here is an ultra simplified infographic on how the body uses energy when it comes from carbohydrates versus when it comes from fat, like in the keto diet. At the bottom half is a comparison of the percentages of macronutrients (carbs, protein and fat) used in an average diet and in a keto diet.

How the body uses carbohydrates vs fats in the keto diet
A very simplified infographic about carbohydrates vs fat metabolism

The keto diet mimics a state of fasting, except that you’re eating. Crazy, huh? And what you are eating is mostly fat – up to 80% of the calories consumed in the keto diet come from fat. Carbohydrates are greatly restricted so that the body does not use them as a source of energy. Under this state of simulated fasting, or ketosis, the body begins to use body fat as a source of energy. Final result: possible weight loss.

Is the keto diet effective for weight loss?

Why do I say possible weight reduction? Well, first of all, not everyone loses weight in the same way. And under the keto diet, the Body Mass Index (BMI, the ratio of weight to height) and individual metabolism dictate how fast someone will produce ketones. So, just because your cubicle buddy lost 20 pounds on the keto diet does not mean that you will necessarily get the same results. Individual factors must always be taken into account before following any dietary plan. Also, just because the body is producing ketones does not necessarily mean that it’s burning fat.

Another thing to take into account is whether ketosis has been achieved. This can be determined more accurately by checking the levels of ketones in the blood, breath, or urine. I recommend to have a health professional involved in this part, since they’ll be better able to explain to you and monitor the metabolic changes that are going on in your body.

And yes, there are many studies that support the effectiveness of the keto diet. Its effectiveness as a treatment for epilepsy – under strict medical control – is well documented.

And it is clear that the keto diet can accelerate weight loss dramatically – but this occurs mostly in the short term. In fact, even though people on the keto diet lose more weight faster than those on a typical calorie restricted diet, in time this effect levels off.

Most of the research done on keto diet effectiveness has not yet been carried out for an extended period of time in order to determine the effectiveness of this diet for weight loss. In addition, the size of the populations used in these studies have been small. We just simply don’t know yet how safe and effective it is to follow this diet over time, or what the possible health risks could be.

Is the keto diet safe?

I personally don’t think the keto diet is the safest choice for weight loss. Some of the concerns that I have, as a health professional, regarding the safety of the keto diet are the following:

  • It’s a very strict dietary plan, which makes it difficult to follow long term. People who cannot sustain this dietary pattern tend to gain back the weight they lost once they stop keto. Plus, in my humble opinion, eating should not be such a complicated biological function!
  • Carbohydrate intake under this diet is way too low. Carbohydrates include fruits, vegetables, whole grains and dairy. These foods are rich in nutrients such as vitamins, minerals, antioxidants, fiber, calcium, folic acid and vitamin D. Therefore, those who follow the keto diet may be missing out in these important nutrients.
  • It’s very low in fiber, which is essential for gut health and heart health. A common complaint I hear from people who follow this diet is the constipation that results from such poor fiber intake.
  • Speaking of carbohydrates, a recent and massive study found an association between both a very high carb intake and a very low carb intake, with increased mortality.
  • It is an extremely high fat diet, which includes large amounts of saturated fat. There is plenty of evidence that underscores the relationship between high saturated fat intake and increased risk of heart disease, and other chronic health conditions. Yes, fats are necessary, but the type of fat must be taken into account. And I’m sorry but, that’s not you, bacon.
  • Speaking of bacon, many people who follow the keto diet see it as a green light to eat more unhealthy meats, fats and highly processed “keto friendly” foods. The diet is followed according to their own interpretation, or that of the internet “health gurus”. A dietary plan as extreme as this one definitely requires a health professional’s advice.
  • There is the possibility of an increased risk of kidney stones and liver conditions. This is due to the high intake of meat and fat.
  • Frequent consumption of processed meats while on the keto diet (for example: ham, sausages, bacon, canned meats), or cured meats, can affect blood pressure. Plus, the World Health Organization classified processed meats as carcinogenic. They found that “consuming 50 g of processed meats every day (equivalent to 4 slices of bacon or 1 hot dog) increases the risk of colorectal cancer by 18%.” Something to think about …
  • It can be a trigger for eating disorders, since there is an excessive focus on food: on what you can and what you cannot eat.

Who should not follow the keto diet

The keto diet is definitely not for everyone. It can increase the risk of certain health conditions or make existing ones worse. Pregnant women should not follow it because the possible risk to this population is unknown yet. This diet should also not be used by people suffering from:

  • Kidney diseases
  • Liver diseases
  • Thyroid problems
  • Eating disorders or a history of eating disorders
  • Gallbladder disease, or people who’ve had their gallbladder surgically removed
  • Diseases of the pancreas

As you can see, there are many factors to consider before jumping on the keto diet. It is not a plan to be followed blindly, even if celebrities and influencers on Instagram promote it otherwise.

Making informed decisions before “going keto”

Consult with a dietetics professional before making any changes to your diet
Always consult with a health professional before making any changes to your diet

I personally continue to recommend un-sexy ways to maintain a healthy weight and promote your health: include a wide variety of nutrient-rich foods, in appropriate portions according to your energy needs, and do regular physical activity. However, for those who do decide to follow the keto diet, I recommend that you consult first with a doctor who can do a complete physical evaluation, and with a dietitian who can make an adequate, personalized meal plan tailored to your needs.

So, is the keto diet safe? Only time will tell if the available evidence is valid, or if it just loses its celebrity status like the South Beach diet. What is evident is that there is no magic solution for achieving a healthy weight and maintaining it long term. Nor is there a fad diet that can substitute good eating habits and healthy lifestyles. This is achieved step by step, over time and with perseverance. I believe that nowadays, it is more than evident that quick “solutions” can bring more problems than they solve. I also believe that it is time to make decisions based on our health and well-being, and not on what is being marketed to us at every turn.

And now on to you: do you think the keto diet is a safe option for weight loss? Have you tried it or do you know someone who has done it? What was your experience? Talk to me in the comments section below!

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Priyanshu Sharma
9 months ago

Thanks, Melissa
Very nice article Also very Healthy article You such doing a great job.
Priyanshu Sharma