Ok, let me preface this post by saying I’m not a doctor or a nutritionist. I’m just a guy who has been on and off the keto diet for the last 4 years and is very susceptible to the keto flu each time I go back to eating keto. Luckily for you, I’ve learned how to minimize the keto flu pains and length of time it takes to get int ketosis.
Near the end of last year, I went on a serious holiday binge. That is my excuse at least. I don’t know if early October to the end of December counts as just a holiday binge or a wreckless eating cycle, but it is the most carbs and sugar I’ve eaten in a while. That meant, my keto flu upon reentering the diet was going to be a rough one. I was right, so I postponed the return until I could take at least a couple of mental days to work through it.
What is the Keto Flu?
Shifting your diet to extremely low carb changes your body’s physiology. Your body is becoming “keto adapted” during this time and needs time to adapt to the changes you are pushing on it.
When you become keto-adapted, your brain and organs and shifting to use ketones from fat as a fuel source instead of glucose/glycogen. It is a process that unfortunately takes some time, but the other side of it feels so much better than before or during the keto flu.
Not a ton of research has been done on this wonderful phenomenon, but many sources seem to think the main causes of keto flu are:
- Lack of electrolytes or electrolyte imbalance
- Sudden drop in insulin levels (which also leads to lower electrolytes)
- Shock to your system
- Detoxing from sugar (it is like a drug withdrawal to some people)
- Not eating enough fat
Does Everyone get the Keto Flu?
There are plenty of lucky individuals who can easily change their diet over and become keto-adapted without feeling the pains many of us are prone to. It’s like those people who don’t get a hangover after a night of drinking. People I envy and loathe oh so much.
The symptoms will most likely be less or non-existent if you already were eating fairly healthy before, are in good health overall, young, and have some fat stores in your body to turn to ketones.
Symptoms of the Keto Flu
While not everyone gets the keto flu, those that do end up getting it will end up with different symptoms at different intensities. There is no way of knowing what you’ll experience until you actually get there. Mine are usually the same each time.
- Brain fog
- Trouble sleeping
- Lack of motivation
- Impaired coordination
- Muscle twitches/spasms
- Sugar cravings
My personal symptoms are usually intense brain fog, headaches, diarrhea, and fatigue/body weakness. The diarrhea usually lasts a day or two and the brain fog is always the last to go.
When does the Keto Flu Hit?
It usually takes a couple of days of restricting your carbohydrates before your glycogen levels get low enough that keto-adaptation starts. This is when the keto flu hits. For most people, this is usually on day 2 or 3 of the diet.
How Long Does the Keto Flu Last?
Depending on a host of factors, it can last anywhere from 3 days to 2 weeks. There are ways to prevent the keto flu and also speed up the process though.
How to Lessen the Symptoms
Take in Electrolytes
Most people feel better after they’ve balanced their electrolytes (sodium, magnesium, and potassium).
You should try to get electrolytes from foods first. Foods like spinach, mushrooms, and avocado are high in potassium and magnesium. If you’re looking for a shortcut, I like to add this electrolyte concentrate to my water.
Exercise can help get your energy back and ward off some of the symptoms. If you’re feeling weak or fatigued, don’t push it. You can make yourself feel worse or risk injury if you attempt a hard workout.
Walking, a light jog, or yoga are all great exercises that you can do while trying to kick the keto flu. Deadlifts and sprints are not.
Lots of the food you cut out are likely full of water. Your drop in insulin could also be causing you to go to the bathroom more. Make sure that you are drinking enough water during your keto-adaptation period, especially if you are increasing your electrolytes.
Aim for 10-16 cups of water per day, but don’t force it if your body is telling you otherwise.
Eat More Fat
A trap that a lot of people find themselves in when starting the keto diet is not eating enough. They go low-carb and low-fat at the same time. You should make sure your caloric intake is right for your body weight and activity level while starting the diet and moving forward.
An easy way to get extra fat into your system is to supplement with MCT oils. They are also quickly converted into ketones which is another hack to get out of the keto flu.
If you’ve never used MCT oil before, be careful at first. Too high of a dose and you will be in a very uncomfortable bathroom situation fast. I find that MCT oil powders are easier on my stomach and don’t cause diarrhea like regular oils do.
The keto diet is low carb and most likely, lower protein than you are used to. If you’re doing the diet right, you should only be consuming something around 0.6-0.8 grams of protein per pound of body weight depending on how active you are.
Too much protein can actually increase your glucose levels, which is bad on the keto diet. Still, the branch chain amino acids (BCAA) in protein are important to building/maintaining muscle, reducing muscle fatigue, lowering blood sugar levels, and a whole host of other physical and mental needs. I started using Biosteel BCAA+ after hearing Dr. Peter Attia recommend it on one of his many interviews with Tim Ferriss.
The first thing I want to say about exogenous ketones is they always seem to taste like poison. I’d love for somebody to point me in the direction of an exogenous ketone product that tastes good since I love the effects of it.
Simply speaking, endogenous ketones are the ketones that are made internally by your body while exogenous ketones are ones that are made outside of your body and taken in the form of supplements. When you are in ketosis, your body is an efficient manufacturer of this incredible fuel source. Some people believe that taking a supplement of exogenous ketones can help trick your body into making your own, which could flip the switch earlier during a keto flu to get you keto-adapted and past the keto flu.
Prepping for the Keto Flu
Plan on starting the diet when you have free time coming up that doesn’t require you to be active or need much brainpower. The worst days will usually be days 2-4, so plan accordingly. Make sure you have food rich in electrolytes available or at least an electrolyte supplement. Avoid starting at the beginning of a workweek when you’re going to be needing to be sharp and energetic.
Techniques for Starting the Keto Diet
One of the more common ways of beginning a keto lifestyle is to just start it. Throw out all of your high carb foods and just start eating as if you are in the middle of the keto diet. The drawback of this is if you have not been eating healthy beforehand, you’re very likely to get a rough keto flu. That’s what happened to me after I tried to start again the day after eating a box of Christmas cookies.
This is more of a slow detox of the high carb foods you were eating before. Start with 3 or 4 days of completely eliminating foods with artificial sugars. After that take out high carb foods like bread, pasta, and pizza for 2-3 days. Then you should spend the following week lowering your carbohydrate intake to 50 grams or less.
Tim Ferriss Keto Hack
Tim Ferriss, the king of efficiencies, lays out this strategy in his book Tools of Titans. I find it a great way to get into ketosis fast, but I think it works better when you were in ketosis before and maybe fell off the wagon for a week or two.
Tim’s 3-day system is:
Thursday (Day 0)
- Eat a ketogenic/low-carb meal in the evening around 6 pm. Your fast begins now
Friday (Day 1)
- After waking up, consume exogenous ketones or MCT oil and (optional) caffeine. Grab a large bottle of water with a few pinches of sea salt and go for a walk.
- Go on a brisk walk for 3-4 hours. This walk is a gentle way to use up the glycogen stores in your muscles and liver.
- During the walk, finish your water and fill it up or buy another one. Add a few pinches of salt to that.
- Being the master of efficiencies, he also recommends scheduling calls for this long walk so you don’t get bored and can optimize your time. He also recommends listening to podcasts, I wonder why.
- Keep taking the ketones and/or MCT oil throughout the day in 3- to 4-hour intervals.
- Oh yeah…don’t eat anything all day!
Saturday (Day 2)
- Test your blood ketone level if you have a ketone testing device like a Keto Mojo kit or Precision Xtra. Don’t rely on the urine strips since they are not the best gauges of ketosis, plus exogenous ketones will light them up regardless of your body’s keto-adapted state. If you’re still not in ketosis (at least 0.5 mmol) repeat the walk.
- Keep NOT eating
Sunday (Day 3)
- Break your fast with a dinner you enjoy. Make sure it is a keto-friendly meal with lots of fat and low carbs.
Sleep as late as you can on your fasting days so your body does all the hard work for you.
Egg and Avocado Diet
A lot of people find it easy to eat nothing but eggs for the first few days of the keto diet. Eggs are high in fat, provide enough calories, and are loaded with vitamins and minerals. They are also cheap and easy to make.
I sometimes follow this, but I’ll also add avocados to the regimen. Avocados are also high fat and low carb, but they also have high levels of potassium and magnesium to keep my electrolytes balanced. If you don’t want to eat a plain avocado, try slicing it up and eating it with some olive oil and sea salt. It tastes good and the olive oil is extra fat and the salt is another electrolyte needed for those first few days.
How to Know When You’re In Ketosis
The easiest and most accurate way to determine if you’re made it into ketosis is to use blood test strips. They will give you an immediate readout of your exact blood ketone levels. Nutritional ketosis kicks in at about 0.5 mmol and the optimal ketone level is 1.0-3.0 mmol. For more information on optimal ketone levels, this post has excellent information.
If you either don’t want to invest in a ketone checker or aren’t a big fan of sticking your finger with a needle, your body should be a good gauge of ketosis. Did you wake up with more energy, a clearer head, and a lower appetite than normal? Congratulations, you might just be in ketosis!