First thing first, the ketogenic flu is not really flu. There is no virus associated with it and it is not contagious.
Ketogenic flu it's just a state that manifests the same symptoms as the flu and it happens when one engages in a low-carb diet after a prolonged period of carb-rich nutrition.
Ketogenic flu is totally reversible, meaning that despite the bad feeling, you are actually in no health danger and you can go quickly back to normal just by start eating normally again (sugar or other carbs).
Let's see how...
Ketogenic Flu Symptoms
The most common symptoms of ketogenic flu usually are:
- lack of focus or concentration.
These symptoms are the direct consequence of a lack of energy at cellular level. The lack of energy is due to the process of adaptation to a different dietary regime which is poor in carbohydrates, hence providing less or no glucose.
The high-carb Curse
Today a large portion of the population adopts high-carb diets. Think about pasta, sandwiches, cakes and pastries, cookies and sweets, soft drinks and alcohol... these items are on our table every day, multiple times per day!
After years of such dietary regime, our body is intoxicated with carbohydrates and it does not know any other way to produce energy than breaking down the carbs into glucose and feeding the cells on glucose. Sometimes, there are so many carbs that the glucose is produced in excess quantity causing serious health problems. This condition is known as Diabetes type 2.
Excess glucose in the blood stimulates the production of insulin (a hormone which main function is to push the glucose inside the cells). A side effect of insulin is the inhibition of the fat-burning process.
This is how high-carb diets lead to obesity.
If you think about it, it is a pretty simple model: high-carbs make too much glucose, too much glucose leads to lots of insulin and diabetic state, too much insulin prevents fat burning and one ends up diabetic and obese.
When we attempt to engage in a ketogenic diet we are asking our body to forget carbohydrates and start producing energy from fat.
Sure the body can do that (we would not have survived 10000 years ago without this ability) but having lived an entire life on carbs, it is a monumental task to change the type of fuel and start running on fat.
Change Diet, Change Fuel
The body needs time to adjust to the new dietary regime and to start burning fat properly.
Once the fat begins to be used as “fuel”, ketones are produced by the liver as byproduct of the fat burning process and the body can effectively provide energy to the cells with ketones.
In fact, our body has the fantastic ability to run either on glucose or ketones, indifferently. The only condition is that the two “modes” are mutually exclusive and they cannot coexist.
In other words:
until you run on glucose you cannot use ketones to fuel your cells and vice versa.
When the ketogenic flu manifests, what really happens is that the residual glucose in the bloodstream keeps high the insulin level which in turn prevents proper fat burning. As a consequence, the body cannot produce ketones and, with the glucose running out, there is no energy source left to sustain vital functions. Sickness follows.
Most resources on the internet suggest to "cure" the ketogenic flu by:
- eating more fat;
- eating more clean carbs;
- taking supplements.
Unfortunately, these three strategies are doomed to fail and here is why:
- the very reason you are experiencing the ketogenic flu is that you still are not able to burn fat efficiently. Adding more fat to the equation won't make it better;
- eating more clean carbs will indeed resolve the issue temporarily but, if your goal is to become keto-adapted, it is only going to prolong your agony. In fact, once you run out of carbs again, the symptoms of ketogenic flu will come again to bother you;
- the ketogenic flu is caused by insufficient energy and there is no supplement that can help you to fix that.
So what to do in order to cure the keto flu for good? ...is there any quick fix?
As a matter of fact, there is... and it is a very simple one.
The Keto Flu Fix
Let's think again about the final goal.
We want to our body to burn fat in order to provide ketones to fuel cells (and lose weight in the meantime).
What prevents the fat-burning process from happening correctly is too much insulin in the blood.
Insulin is produced in response to a concentration of glucose in the bloodstream.
Glucose comes from the intake of carbs from food.
So, it is clear that in order to kickstart the fat-burning process we must turn to zero the insulin.
In order to turn to zero the insulin, we must remove all glucose from the bloodstream.
In order to remove all glucose from the bloodstream, we must stop eating carbs entirely.
Now, this might not seem a big news (we all know that on a keto diet we are not supposed to eat carbs)... BUT... when you add that the insulin level tends to zero after 20 hours from the last meal, an interesting concept starts to take shape.
In a previous article about the ideal ratio of macronutrients on a ketogenic diet, we have seen how it is impossible to eat a meal with zero carbs. This means every time we eat there will be some glucose released into the bloodstream and an insulin response will follow.
The effect of this response can last up to 20 hours.
What if we stop eating at all for a period longer than 20 hours?
This way the insulin level will certainly drop to zero and the fat-burning process will start to take place undisturbed. When the fat-burning process is working correctly, ketones will be released and quickly replace the glucose in the function of providing energy to the cells.
The simplicity of this mechanism is absolutely brilliant.
So what is the definitive solution to get rid of the ketogenic flu?
Fasting is the Key
Instead of looking for complicated workarounds, products or magic foods, do yourself a favor... simply stop eating.
Begin by fasting for 22 hours. No solid food allowed, just water, coffee or tea (no sugar!).
Fasting of 20+ hours and eating ONE reasonably-sized carbs-free me per day will kickstart the ketogenic process in about 2 days. On the 3rd day you might experience some discomfort, as a light version of the ketogenic flu.
In general, you'll be in ketosis by the end of day four and with no big distress.
I used to follow a "regular" ketogenic diet and I always experienced a big episode of ketogenic flu around day three. It was horrible. Dizziness used to haunt me for days after that, making it very difficult for me to function properly at work and in a social environment.
Everything changed since I started daily fasting. Now I practically never experience these symptoms and I go straight into ketogenic state.
Dozens of people followed my suggestion and reported the same smooth transition from normal to ketogenic. Only a few reported headaches and nausea around day three but all symptoms quickly resolved in less than a week.
Dr. Jason Fung partially addresses this issue in his book "The Complete Guide to Fasting". He treated hundreds of patients with fasting and sustains that none of them experienced any particular problem with keto-adaptation.