The Side Effect Of The Keto Diet That No One's Talking About — And How To Avoid It

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The ketogenic diet has made waves this year for its myriad benefits, which range from improvement in brain function to healthier blood sugar levels, stabilization of diabetes, reduction in seizures, improvement in mitochondrial health, dementia prevention, and so much more. Many moons ago, the researchers at Johns Hopkins found that fasting and avoiding carbohydrates had positive effects on blood sugar and insulin, which provided benefits to patients with neurological imbalances. Since long-term fasting is not realistic, the ketogenic diet was born to mimic the benefits of fasting by consuming high fat and little to no carbohydrates. When the body does not have sugar or glucose readily available, it essentially tricks the body into thinking it is fasting.

In many scenarios, there is vast improvement to overall health by shifting the diet to becoming ketogenic, but some people experience adverse reactions from the keto diet that deter them from continuing. Experts speculate that symptoms arise due to sugar withdrawal, metabolic issues, or not being fat adapted (meaning your body does not know how to use fat as fuel for energy) but there is another piece of the puzzle that is often being overlooked. As we shift the body into a fat burning state, we need to consider what is being mobilized from the fat tissue that can be causing adverse symptoms. 

The rundown on ketosis.

Ketogenic diets work through the elimination of sugar, also known as glucose, in the diet and the introduction of fat. The goal is that eliminating glucose from the diet forces the body to find another source of energy. After we cut sugar and carbs in our diets, the liver and muscle tissue still contain about 24 hours of glucose. When the glucose stores are burned up, the body shifts into a fat-burning state—which is what we call ketosis.

The body using fat for energy was an evolutionary survival mechanism. Shifting the body into a state of ketosis allowed our ancestors to burn fat for energy in times of famine, which allowed them to go longer periods of time between meals.

Shifting into a fat-burning state to get the body into ketosis can promote weight loss, decrease inflammation, and improve brain health, but it can also have less than desirable effects. In the early stages of embarking on the ketogenic diet, some people may develop an array of symptoms that resemble the onset of a flu, also known as the "keto flu."

What is the keto flu?

The most common symptoms of the keto flu include fever, nausea, headache, body aches, chills, literally flu-like symptoms. A complete list of symptoms can include:

  • Fatigue
  • Cravings for carbs and sugar
  • Dehydration
  • Loss of appetite
  • Constipation
  • Diarrhea
  • Heartburn or other symptoms of indigestion
  • Low motivation to exercise and poor recovery from workouts
  • Brain fog
  • Dizziness
  • Trouble sleeping
  • Moodiness or irritability

Some experts believe that the reason for the ketogenic flu is unknown, and others report that the symptoms are often due to sugar withdrawal or a metabolic reset. It is probable that kicking the habit of sugar can induce withdrawal symptoms that cause symptoms similar to the keto flu. In some scenarios, though, people are developing these symptoms in the absence of high amounts of sugar in their diet, so the question stands, what else could be the contributing factor?

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What causes the keto flu?

As I mentioned, the foundation of the ketogenic diet is to shift the body from a sugar-burning state to a fat-burning state. As you enter this fat burning state, you can begin to mobilize toxins out of the fat tissue. A lot of the toxic burden from environmental chemicals lives in the fat tissue. These can come from heavy metals, pesticides, herbicides, molds, plastics, and certain ingredients in packaged food products.

Our bodies are designed to detox naturally, but over time our inborn "filtration" systems become overloaded, which can make the detoxification process more difficult. The example that I give to many of my patients is in reference to how a vacuum works. If you have a new vacuum that you use every day for a month without ever dumping the filter, you will find that at the end of the month your vacuum doesn't really work anymore. But if you dump the filter, you can continue to use your vacuum and it will function like new. So over a lifetime, our bodies are bombarded with different chemicals and toxins that it is constantly filtering out. It then comes to a point when our detox organs like our liver, gut, kidneys, and lymphatic system cannot filter like they used to. This is what causes us to trap more toxins and start to feel increasingly worse. These are not always extreme symptoms; they are the symptoms that we ALL complain about. It is the fatigue, not waking up refreshed, feeling foggy, and more forgetful than our younger selves.

There are many signs and symptoms that many of us experience that are connected to toxic burden. In particular, if you have toxins in your fat cells, you may experience some of the following:

  • Cellulite
  • Inability to sweat or you only glisten after a workout
  • Water retention or swelling
  • Dense breasts or fibrocystic breasts
  • Circulation issues like Raynaud's disease, or you are just generally always cold
  • Distended belly. This also applies to people that are generally skinny but say they have belly fat
  • Skin disorders including acne
  • Varicose veins
  • Swollen lymph nodes/glands
  • Brain fog or memory loss

How to overcome the keto flu.

If you have many of the symptoms listed, you may have toxic burden. If so, before switching to a ketogenic diet, you may want to consider how you can support your body's ability to detox. There are a few things I use to consider when choosing what are your best therapies. (Disclaimer: All content and suggestions are for informational purposes only. It is not intended to be a substitute for professional medical advice, and is not intended to serve as a substitute for the consultation, diagnosis, and/or medical treatment of your physician or health care provider.)

  • Dry brush toward the heart to get your lymph moving. You also get a nice exfoliation as you do it. 
  • Jump on a mini-trampoline to help drain lymph.
  • Support your liver with celery juice and cruciferous veggies.
  • Ease up on the saturated fats from animal products like cheese, milk, and butter. Opt for more plant-based fats like avocado, coconut, olive oil.
  • Consume soluble fiber from steel-cut oats to make sure everything is bound and moving. Soluble fiber has many benefits for detoxification.
  • Use chlorella to bind toxins and eliminate them through your bowel movements.
  • Make sure to stay hydrated and include electrolytes in your regimen. 
  • Drink dark tart cherry juice to cleanse the kidneys.
  • Be cautious with your protein selection. Look for pastured meat and decrease consumption of pork products, which can store a lot of toxins in the fat.
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One keto diet does NOT fit all.

Another important consideration with the ketogenic diet is reviewing different versions of the diet. There is no "one size fits all" keto diet because every person is unique and each person's needs are different. Some might thrive on a Mediterranean keto diet, which mainly focuses on consuming fish, seafood, olives, low-carb vegetables, salads, and olive oil. Some people also have food allergies. For these reasons there are a variety of eating versions within the ketogenic diet. I often advise my patients to be cautious with the overconsumption of cow dairy. In these cases, I might suggest opting for goat or sheep dairy, which is usually better digested by the body. I also express the importance of clean protein. Gravitating toward pasture-raised organic meats is key. When shopping for red meat, look for grass-fed and grass-finished, which ensures that the animal ate grass its whole life.

My conclusion?

When embarking on the ketogenic diet, symptoms can arise as the body shifts into a fat-burning state. These symptoms include headache, fatigue, irritability, and achiness, which is better known as the "keto flu." These symptoms can arise due to sugar withdrawal but can also be due to the mobilization of toxins in fat tissue. There are different strategies to support the body with detoxification, depending on your body, that can prevent the keto flu symptoms. You also want to consider what type of ketogenic diet you try.

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