By now the benefits of going keto are well established – fast fat loss, enhanced energy and boosted brain power to name a few. But so are the side effects. Going into the state of ketosis can lead to the dreaded keto flu, fatigue, carb cravings and bad breath. In this article we’ll take a look at the top 10 keto diet side effects and how you can minimize them.

Keto Side Effect #1: Dizziness

It’s very common for people to get a feeling of dizziness when they make the switch from a glucose based to a ketone based energy system. The most common reason is that they are water depleted. Another factor is the loss of electrolytes such as potassium, magnesium and calcium.

The fix to this one is quite simple. Make sure that you are drinking plenty of water in the first two weeks of your keto switch. In fact, during this transition period, you should actually drink more water than usual during this phase. Up your intake to 3 liters (0.65 gallon).

You should also make sure that you are getting plenty of electrolytes through such keto approved vegetables as broccoli and spinach.

Dizziness can also be the result of a lack of nutrient intake. Make sure that, during the switch over period to keto (the first two weeks), you maintain your daily caloric level to meet your requirements.

You can work out your daily requirement with this formula . . .


66.5 + (13.75 x weight (kg)) + (5 x height (cm)) – (6.76 x age)


655 + (9.56 x weight (kg)) + (1.85 x height (cm)) – (4.68 x age).

Let’s work this out with an example of a 68kg woman who is 24 years of age.

655 + (9.56 x 68) + (1.85 x height 168) – (4.68 x 24)

= 1503 calories

So, our 24-year old woman would require 1503 calories per day simply to stay alive. This does not take into account any physical activity. To work out how many calories we actually need to take into our body every day in order to meet ALL of our needs, we need to multiply the BMR by an activity factor.

Exercise LevelActivity Factor
No Exercise1.2
Exercise 1-3 times per week1.375
Exercise 3-5 times per week1.55
Exercise 6-7 times per week1.725
Very labor intensive job1.9

To work out your daily caloric requirement, simply multiply your BMR by your selected activity factor.

So, if we return to our 24-year old woman, let’s assume that she works out at the gym 3-4 times per week. Therefore, she would select an activity factor of 1.55.
1503 x 1.55 = 2330 calories

We have now worked out the caloric maintenance level for our young lady. If she consumes 2330 calories per day, so long as she is following sound macronutrient guidelines she will be getting all of the nutrients that her body needs to function.

Keto Side Effect #2: Increased Urination

A very noticeable side effect when you make the switch to keto is that you will experience more visits to the bathroom. The reason for the more frequent urination is that your body is getting rid of glycogen from its system.

When you are operating off a glucose based energy system, you will build a reserve of energy in the form of glycogen. The body is able to store around 600 grams of stored glycogen. When you begin the switch to keto, your body will start to use up this glycogen. Now, the thing with glycogen is that three quarters of it is water. So, when you reduce your carb intake to initiate the utilization of glucose for energy, you will, naturally, have an increase of water release from the body in the form of urination.
This glycogen based water loss can actually leave you dehydrated.

This is yet another reason to increase your intake of water during the two week transition to keto. Add a pinch of salt to your water in order to assist the body to retain this water rather than releasing it through urination.

Keto Side Effect #3: Fatigue

When it comes to keto and energy, you’ve got to focus on the long term. After you get through the transition phase, you will be amazed at how much more energy you’ll have on a ketone based energy system. During the switch over, however, the opposite will occur.

In that first two weeks, you will experience a lack of energy, you’ll feel more run down and lethargic than you normally do. That’s because you are no longer filling your body with carbs, sugar and glucose for energy. You will also be experiencing electrolyte imbalances during this transition phase.

Switching from a glucose to a ketone based energy system takes time. It’s only natural that, during that period of time, you will have an energy drain. There’s not a lot you can do about this energy drain. If you can it is a good idea to plan your switch to keto during a break between gym workout routines.

You will definitely be dragging your tail if you try to train with your usual intensity during your switch to keto.

Keto Side Effect #4: Constipation

According to one study, as many as 65 percent of people who make the switch to keto will experience constipation during their first two weeks of making the change. That means that they have fewer than three bowel movement over the course of a week.

The researchers, however, are not certain why people who get started on keto experience constipation. It may be because keto followers will naturally lower their intake of fiber, which is a well -known stimulant of bowel movements.

You should make every effort to consume a healthy dosage of fiber. You can get fiber through green leafy vegetables. In addition, you can take a fiber supplement, such as psyllium husk.

Another reason for keto induced constipation may be lack of water intake, combined with lower electrolyte levels. There are also studies which show a link between a high intake of saturated fat and constipation. It is believed that saturated fat may suppress the growth of healthy bacteria in the gut, leading to constipation.

Keto Side Effect #5: Muscle Cramps

Electrolyte imbalances are bound to occur during the transition to a ketone based energy system. They are responsible, at least in part, for many of the side effects that we’ve already spoken about. When it comes to muscle cramps, however, electrolyte imbalance is the main culprit.

The major electrolyte that causes muscle cramps is magnesium. A lack of it will impact upon the ability of your muscles to contract and relax. Secondary electrolytes that are important for preventing muscle cramps are calcium and potassium. Dehydration can also add to the muscle cramp issue.

You can address the issue of muscle cramping during your keto transition by taking an electrolyte enhanced (carb-free) fluid.

Keto Side Effect #6: Poor Sleep

It is not uncommon for people to experience interrupted sleep patterns during their switch to keto. Once you are adapted, you will find that you sleep will be much better, but until you reach that stage, you will, more than likely, have difficulty getting to sleep. You may also wake up feeling as if you haven’t received the restful slumber that you formerly enjoyed.

Sleep problems are connected with the elimination of carbohydrates from your diet. Research has indicated that a diet that is high in carbs will boost the levels of the amino acid tryptophan in the body. This amino acid is a precursor to the hormone serotonin. So, the more tryptophan you have in your system, the more serotonin will be produced. Serotonin regulates a number of functions in the brain, including sleep.

You can counter the lower levels of tryptophan due to carb withdrawal by consuming keto approved foods that have higher levels of this amino acid. These include chicken, hummus and eggs.

Increasing your magnesium intake will also improve your quality of sleep. By balancing out the glutamate / gabba ratio, as well as increasing the body’s release of melatonin (the key sleep hormone), magnesium supplementation can help you to get a deep, more rejuvenating night’s sleep.

You can also help promote better sleep by relaxing in the evenings with a warm bath, winding down in the hours before bed by reading a book and keeping electronics out of your bedroom.

6 Step Sleep Make-Over

  1. Establish a sleep routine: Have a wind down period in which you reduce your activity level and mental stimulation as you progress toward bedtime. Go through the same routine every night, including having a set bedtime. Your routine may include switching off your technology, including your phone, at a certain time (well in advance of retiring), having a bath, brushing your teeth, etc. Such habits help you to get ready both physically and psychologically for sleep.
  2. Get up at the same time each day: Regardless of when you go to bed, maintain a consistent time that you rise in the morning.
  3. Control stress and worry by giving yourself downtime and settling differences quickly. Consider setting aside a worry time each night before going to bed. Write down all of your worries and what you are going to do about them. If one of those worries comes into your mind as you are trying to get to sleep, tell yourself “I’ve already dealt with that and I know exactly what I’m going to do about it tomorrow.”
  4. Avoid caffeine, alcohol and tobacco. Don’t drink, coffee, tea, soft drinks and chocolate within 2-3 hours of going to bed. Alcohol before bedtime can result in restlessness and uneven sleep. The nicotine in tobacco is a stimulant, making it harder to get to sleep.
  5. Make your bedroom as dark as possible, as cool as possible and as quiet as possible: The best temperature is 68 to 72 degrees Fahrenheit. Distracting noise can be drowned out with earplugs, soft music or a white noise machine.
  6. Unplug your technology: Technology is having a huge impact upon the quality and quantity of our sleep. Most technology screens have a bluish tinge to them. This has the effect of restricting the release of melatonin into the body. The bottom line is to make your bedroom a technology free zone. Be strict on yourself and don’t even allow your smart phone in.

Keto Side Effect #7: Nausea

Dehydration and constipation will, naturally, interfere with your body’s normal digestive processes. One result of this, which is felt by many people when they transition to keto, is nausea. The very fact that you’re also upping your protein and fat intake are also contributing factors to this state of queasiness. Fat and protein are more difficult to digest than carbohydrates. It takes longer to digest them than it does carbs – and it requires more in the way of digestive enzymes, stomach acids and bile.

There is not a lot you can do about this nausea apart from taking a digestive enzyme.

Keto Side Effect #8: Bad Breath

Keto breath is one of the most well-known side effects that people experience when going keto. It is characterized by a strong pain-like odor coming out of the mouth of the person switching to keto. Some people also experience a metallic taste in their mouth.

Keto breath is the result of the release of a ketone side effect by the name of acetone through the breath. In that regard, bad breath is a positive thing in that it lets you know that you are, actually, in the state of ketosis.

However, the strong odor that comes with getting into keto is probably something that you would rather do without. So, what can you do about it?

The good news is that your keto breath will lessen the deeper into ketosis you get. In the meantime, here are six things you can do to lessen its effect:

  1. Be as strict as possible on your carb limitations. Keep your level down to under 20 grams. This will help to speed up the process of using up the glycogen that is stored in your muscle cells. It will also help the acetones to be more fully used up for energy rather than being breathed out of your mouth.
  2. Couple your keto adaptation with intermittent fasting. Doing so will help to keep your insulin levels down to speed up keto adaptation.
  3. Drink your 3 liters of wter each day. This will encourage the excess ketones to exit the body through your urine, rather than out of your mouth.
  4. Eat more chlorophyll rich foods. Chlorophyll is a natural body cleanser. You will find it in green leafy vegetables.
  5. Make sure that you are on top of your oral hygiene. Poor oral hygiene will not cause keto breath, but it can exacerbate it. A good habit to get into is to practice what is known as oil pulling. This involves taking a mouthful of coconut oil and swishing it around for about ten minutes and then spitting it out before immediately brushing your teeth. Get into the habit of doing this daily first thing in the morning before eating.
  6. Brush your teeth regularly. You should do this twice daily. Other good daily oral hygiene habits include flossing and scraping your tongue.

Keto Side Effect #9: Headaches

Keto headache is another common symptom during the keto transition process. Most people experience it as sharp, stabbing brain pain. The cause is carbohydrate withdrawal and loss of electrolytes.
Another potential cause of keto headache is dehydration.

Dehydration actually causes your brain to get smaller. It also leads to a reduced blood flow to your cranium. That means less oxygen also getting to the brain.

Dehydration generated headaches evidence themselves as dizziness and what is commonly referred to as brain fog.
Migraine headaches are caused by a lack of electrolytes, mainly magnesium.

Of all the side effect that people experience during the transition to ketosis, headaches are, thankfully, one that will disappear the fastest. Once you transition to keto, they will go away. That will happen when your body has used up all of its stored glucose. This can take anywhere from 3 days to several weeks.

All of the other things that have been mentioned to limit other side effects – drinking 3 liters of water each day, keeping your carb intake under 20 grams and taking an electrolyte enhanced fluid – will help to minimize the effects of keto headache during your transition to keto.

Keto Side Effect #10: Carb Cravings

When they start to severely restrict their carbohydrate intake, many people experience intense carb cravings. This craving is especially intense over the first two or three days, before the body has made the switch to a ketone based energy system. Your cravings will subside, and eventually disappear, when your body becomes adapted to using ketones as its primary energy source.
Are you addicted to sugar?

That fact that you’re human makes it highly likely. You see, the human body is hard-wired for sugar. The taste buds go crazy for it.

They yearn for their fix.

Every single one of the tens of thousands of taste bud receptors in your mouth have special sweetness receptors. Each of them is also connected to the brain’s pleasure center. In effect, they receive a reward for satisfying the body’s sugar fix.

But the craving isn’t just in your taste buds. Recent research has discovered that sugar taste receptors are also located in the stomach, esophagus and even the pancreas.

All of them are linked to your appetite.

When it comes to addiction, cocaine’s got nothing on sugar.

According to Dr. Pamela Peeke, author of The Hunger Fix, “Animal studies have shown that refined sugar is more addictive than cocaine, heroin, or morphine. An animal will choose an Oreo over morphine. Why? This cookie has the perfect combination of sugar and fat to hijack the brain’s reward center.”

For more than 80 years now, food manufacturers have been well aware of the human sugar addiction. They use this knowledge to increase their profit margins in countless ways.

  • Sugar creates a consumer addiction to a manufacturer’s product
  • Sugar can make products fry up bigger and look more puffy
  • Sugar can prevent foods from going stale

As a result, sugar is in everything. It’s no wonder that those who make the choice to severely limit their carb intake are going to experience withdrawal symptoms.

The only thing that you can do when you are experiencing carb withdrawal symptoms is to grin and bear it! Going cold turkey (or at least limiting your intake to 20 grams) is the pain that you will have to go through in order to free yourself from sugar addiction for the rest of your life!

Keto Side Effect #11: Keto Flu

We’ve saved the worst for last – but not really! The keto flu is actually the combination of all of the above symptoms hitting you at the same time. That list of symptoms may include some or all of the following:

  • Nausea
  • Vomiting
  • Constipation
  • Diarrhea
  • Headache
  • Irritability
  • Weakness
  • Muscle cramps
  • Dizziness
  • Poor concentration
  • Stomach pain
  • Muscle soreness
  • Difficulty sleeping
  • Sugar cravings

For most people, these symptoms will last for less than a week. The ways to minimize the symptoms of keto flu will naturally encompass much of the advice that has already been given. That includes:

  • Staying well hydrated by drinking 3 liters of water per day.
  • Replacing electrolytes.
  • Avoiding exercise (remember, schedule your keto transition between training programs).
  • Get plenty of sleep (and follow the six step sleep make-over)
  • Eat plenty of healthy fats


The old workout maxim ‘No Pain, No Gain’ is appropriate when it comes to switching to the keto diet. You will go through some uncomfortable days as your body transitions to transforming itself into a fat burning machine. However, the long term benefits that you’ll experience – faster fat burn, masses more energy and a sharper mind – will make that sacrifice well worth it.

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