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Hazards of the Keto Diet: Why is Keto So Controversial?

by Dr. Nancy Rahnama

Director of Health & Nurition

The ketogenic diet, commonly known as “Keto” has taken the world by storm in recent years. Men and women who have struggled to lose weight for years have finally found a way to shed the pounds, and that’s a good thing, right? Well, it definitely can be. The keto diet, as we covered in our previous article Dr Nancy on Keto: Is it as Beneficial as it is Popular? can help reverse diabetes, reduce blood pressure, and decrease inflammation, but it’s certainly not without its risks.

We asked Dr Nancy about why this diet is so controversial and why it shouldn’t be embraced without medical supervision. Read on to find out what she said.


What are some common “hazards” of the keto diet?

1.    Keto Flu

The number one is something known as “keto flu.” When someone follows the keto diet, the body switches from using sugar as a source of energy to using the body’s stored fat through a process known as ketosis. When the body enters this state it produces ketones, which are removed from the body through increased and frequent urination.

It’s this process that leads to the “keto flu” symptoms, which often include fatigue, dizziness, inability to think clearly, irritability, nausea, and muscle soreness – many of the same symptoms we experience when we have the flu. The frequent urination also means the body loses more water and electrolytes, which, unless properly managed, leads to dehydration and exacerbates these symptoms.

In addition to all of this, the removal of carbohydrates as a source of energy completely from the diet results in increased sugar cravings, brain fog, and difficulty concentrating. You can see why so many people don’t make it past this phase of the diet!


2.    Constipation

It’s often easy to demonize carbohydrates in all their forms, but it’s important to remember that fiber is a form of carbohydrate and is essential to healthy digestion. Without a sufficient intake of fiber, we are likely to become constipated and experience digestive discomfort.


3.    Dehydration

We touched on dehydration in our first point, but it’s worth mentioning here again, as it can become a much more serious risk factor of the diet. Beyond headaches and other typical dehydration symptoms, the keto diet can result in kidney stones, acute kidney injury in extreme cases, and the loss of electrolytes as sodium, magnesium, and potassium can result in muscle cramps, twitches, and even cardiac arrhythmias, as electrolytes are essential for normal, healthy function of the heart.


With all of these hazards, why is the keto diet so popular?

In the right circumstances, the keto diet can help high-risk patients, such as those with epilepsy or Type 2 Diabetes gain control over their condition. For patients who find it difficult to stray from the typical traditional American diet, which is high in sugar, dairy, red meat, and starchy carbs, the keto diet often proves to be the only diet they are willing to stick to.

It’s important to remember, however, that not all patients are appropriate candidates for keto, especially those with chronic conditions. While keto can prove to be beneficial for these patients with high blood pressure, diabetes, and other conditions that often prove fatal, the diet must be undertaken under the strict supervision of a doctor. This is because people with these conditions are often on a range of medications to keep their condition under control, and the sudden and drastic change in diet will also require constant monitoring (via laboratory results), tweaking, and likely a change in medication throughout the diet.


Is there anything patients can do to avoid these hazards?

To avoid side effects, first talk to your doctor and make sure you have a full plan about what you’re going to eat and drink and in what amounts. You’ll need to increase your water intake before you start and continue to drink more water than normal for the duration of the diet.

It’s also a good idea to supplement with sodium, though make sure you talk to your doctor about this, as it may not be suitable if you have high blood pressure or a similar issue. Some patients may need a prescription potassium supplement – I start all my patients following the ketogenic diet on a magnesium supplement too, since it is an electrolyte that can be taken with a low risk of overdose.

If someone continues to have any of the symptoms we discussed above, despite increased hydration, they should reintroduce vegetables and fruits to their diet and contact their doctor.


Would you recommend the keto diet? How should it be used, and by whom?


It’s important to note that the keto diet is not a healthy long-term diet. It’s not balanced, and by cutting down your carbohydrate intake so severely, you’re also going to cut down your opportunity to eat sufficient essential micronutrients which are essential for healthy cell function throughout the body.

Keto may result in serious micronutrient deficiencies, which can have other consequences, many of which are severe, and some even fatal.


The keto diet can be used for short-term fat loss provided it is done under the supervision of a doctor, or when recommended by a doctor for someone suffering from seizures. It should only be used when recommended by a doctor, ideally only when other, healthier methods of fat loss (such as eating a healthy, balanced diet with a calorific deficit and an exercise regime) have been exhausted.

The ketogenic diet can help some patients lose weight quickly and cease being at high risk of health problems, but that doesn’t mean it should be the answer for everyone who is overweight. In most cases, a balanced, healthy diet, increased water intake, and increased exercise as a lifestyle change, and not as a diet, is the best solution. If not done properly, the keto diet can cause far bigger problems in the quest to solve a much smaller one that can often be solved with other lifestyle changes.



Dr. Nancy Rahnama, MD, ABOM, ABIM, is a medical doctor board certified by both the American Board of Obesity Medicine and the American Board of Internal Medicine. Her specialty is Clinical Nutrition, that is, the use of nutrition by a medical doctor to diagnose and treat disease. Dr. Rahnama has helped thousands of people achieve their goals of weight loss, gut health, improved mood and sleep, and managing chronic disease. In addition to her private practice in Beverly Hills, she is also the co-founder and Director of Nutrition for Dr Nancy MD.


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Try our products risk-free. If you are unhappy for any reason, simply return it within 60 days of receiving it and we’ll give you a full refund. It’s that simple.