What is the ‘Keto Flu’?

It’s quite common for people starting out on a ketogenic diet to experience what is commonly referred to as the ‘keto flu’. Of course, this has nothing to do with influenza, but it does share some of the milder symptoms. It generally occurs during the first few days or weeks when your body is adjusting to the new diet and transitioning from burning carbohydrates as a fuel source to burning fats. 

Once again, we had the pleasure to invite Dr. David G. Harper, co-author of BioDiet: The Scientifically Proven, Ketogenic Way to Lose Weight and Improve Your Health, to help us understand what to expect should you experience the keto flu and how to alleviate any symptoms. Once your body has fully adapted to a ketogenic diet you’ll be well on your way to enjoying its health benefits.

For those of you who are considering a ketogenic diet, we suggest you reference our previous articles in this series, where Dr. David G. Harper dispels 7 common myths regarding the diet, and also shares important pointers on what to make note of before you make the dive.

 D: Dr. David G. Harper

Embarking on a lifestyle change can be intimidating for some, and hearing about the keto flu may derail their efforts. To dispel any fears about ketogenic diets, can you share with us what exactly the keto flu is?

D: Some people who embark on a ketogenic diet can experience side effects early on as their body adjusts to this new way of eating. These symptoms, which are generally transient and mild, can include lightheadedness, dizziness, headaches, digestive issues or a mild upset stomach. The cause is often the result of dehydration or a salt imbalance and can typically be easily addressed by drinking more fluids and adjusting salt intake.

As I have mentioned in the previous articles in this series, the ketogenic diet not only a significant lifestyle change, it is also a physiological one so it isn’t a diet you want to jump in and out of in for short-term weight loss. It requires a few months of commitment in order for your body to adapt and for you to see the diet’s full benefits.

What’s happening with our bodies as we bio-adapt that leads to these symptoms?

D: In the initial phases of adopting a ketogenic diet, your body is breaking down glycogen, which is stored energy derived from carbohydrates in your muscle and liver cells. When you significantly cut back on your intake of carbohydrates, your body turns to the glycogen for energy. Since glycogen storage requires a lot of water, as we deplete the glycogen we also excrete the excess water, hence the diuretic effect. For every gram of glycogen that’s broken down, you lose four grams of water, which is why it’s very important to stay super-hydrated.

What does it mean to stay ‘super-hydrated’?

D: It simply means to drink much more water than you usually would and not just when you are thirsty. I would recommend that individuals begin their day by drinking up to a liter of water in the morning before they consume any other food or drink. It will take about 20 minutes for the water to be absorbed and this should help with most keto flu symptoms associated with dehydration.

We also recommend drinking more water because most of us are already in a chronic, mildly dehydrated state due to our daily habits. For example, you may start your morning with a cup of coffee before you have had any water, and because caffeine is a diuretic, it further dehydrates you. Later in the day you may enjoy a glass of wine over dinner, and since alcohol is also a diuretic you become further dehydrated. So, drinking more water is important for everyone, but especially for those on a ketogenic diet.

You also mentioned an imbalance of salts as one of the culprits of the keto flu. What causes this imbalance?

D: Reduced carbohydrate consumption results in reduced blood sugar and insulin levels, which, along with weight loss, is why many people adopt a ketogenic diet in the first place. But insulin promotes water retention by inhibiting salt excretion so as insulin levels drop, the kidneys excrete sodium and water follows it. This means that not only do you have to stay super hydrated on a ketogenic diet you also need to replenish the salts, especially sodium, in your body. 

This is especially true because on a keto diet you’re not eating any processed foods, which are a major contributor to our salt intake. Half our total salt intake comes from this source including bread, which contains a lot of salt. So, as you remove these foods from our diet, you can be more liberal with the saltshaker. And to ensure you are also getting the other important salt compounds I suggest taking supplements with magnesium, calcium, sodium and potassium.

In addition to staying well hydrated and increasing our salts, are there other things we can do to combat keto flu symptoms? 

D: I’d suggest referencing our article on important pointers before starting a ketogenic diet, which provides details on how you can prime your body to ensure it’s ready for the transition. This includes crucial steps such as consulting your physician beforehand to ensure you are not on any prescriptions or have any health preconditions that would deter you from adopting a ketogenic diet. 

If people do get the keto flu, how long can they expect it to last?

D: For most people when they begin to severely restrict their carbohydrate intake, it takes about three to five days before they start experiencing any discomfort. While in general, it takes about 12 weeks for the body to fully adapt metabolically, the symptoms of the keto flu may be felt for a few days to a few weeks, but once you complete this transitional phase the benefits are exponential.

So for those who experience the keto flu, what are some of the good things they can look forward to once they’re through it. 

D: There are lots of benefits to adopting a well-formulated ketogenic diet like the BioDiet! 

·      Fat loss – in my past experience, there is typically 20 – 25 pounds of fat loss in men and about 10 – 15 pounds of fat loss in women. The fat loss tends to be in the mid-abdominal region, which tends to be inflammatory fat tissue. This is caused by the fact that your body starts burning ketones and using stored fat as its new fuel source.

·      Improved skin quality and tone – due to the high fat intake.

·      Improvements in mood – in most cases we see people experiencing an overall improvement in their wellbeing. People with mood disorders often report it being resolved and those who are depressed may, under physician supervision, get off their medicine altogether.

·      Less inflammation – reduction in systemic inflammation in the body. In other words, fewer aches and pains.

·      Clarity of thought and mind – As we age, our brains may build up insulin resistance, which leads to ‘brain fog’ (ie. being more forgetful as we age). As the brain transitions to burning ketones as a new fuel source, this combats the insulin resistance build-up. Dr. Harper’s readers and colleagues refer to this as ‘The Harper High’, where they feel as if their mind is operating much more efficiently and clearly.

·      No Hunger Pangs – a keto diet maintains your blood sugar levels at a low level and moderates your insulin levels, which moderates your sense of hunger. So, with everything in check, you shouldn’t experience hunger pangs or feel the need to overeat.

Again, we want to emphasize that keto flu symptoms may vary from person to person, and some may experience mild symptoms while for others it may last for a longer period. However, given all the health and wellness benefits above, it is evident that a switch to the keto diet is well worth the commitment.

We’d like to thank Dr. David G. Harper for taking the time to provide us with valuable insights into the keto flu and advice on how to combat its symptoms. His book, BioDiet, covers everything you need to know about a well-formulated ketogenic diet and comprehensively outlines how one can safely and successfully adopt the diet. BioDiet is available in softcover at your local bookstore or online at Amazon, Indigo and Barnes and Noble. It’s also available as an eBook and Audiobook.

ABOUT DR. DAVID G. HARPER

As an educator, researcher and health consultant, Dr. David G. Harper, has studied the impact of diet on human health for many years. The culmination of that extensive work is the BioDiet, a well-formulated ketogenic plan that works with the body’s natural processes to improve health and reverse decades of damage caused by our collective carbohydrate addiction.Dr. Harper and Dale Drewery adopted the BioDiet in 2012 and the weight loss and health improvements they experienced led him to counsel hundreds of people on the Biodiet with similarly consistent and impressive results.

Dr. Harper is an associate professor of kinesiology at the University of the Fraser Valley and a visiting scientist at the BC Cancer Research Center, Terry Fox Laboratory. He holds a PhD from the University of British Columbia and completed a post-doctoral fellowship in comparative physiology at the University of Cambridge. He is on the scientific advisory board of the Canadian Clinicians for Therapeutic Nutrition and is a member of the Institute for Personalized Therapeutic Nutrition.