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Everything You Need To Know About Ketosis Symptoms including Keto Flu

The ketogenic diet is a lot more than just a low-carb meal plan. It's a specifically calibrated ratio of macronutrients designed to transform your metabolism and change the way your body processes fats. The key to success on the keto diet is ensuring that you've reduced your carbohydrates for long enough to ensure that your liver begins turning fat into ketone bodies for fuel. This sustained transformation puts your body into a state of ketosis, which is where all the magic happens.

You've likely heard a lot of positive things about the keto diet, or you wouldn't be interested in getting into ketosis. While the ketogenic diet was initially developed to help treat children with epilepsy, the anti-inflammatory, blood sugar-regulating aspects of this way of eating have given rise to its popularity for weight loss, mental clarity and even helping reverse Type 2 diabetes [1][2]. It's also a completely natural metabolic state that our ancestors would have utilised in times where carbohydrates where low or there was no food at all available. 

But how do you know if you've reached ketosis? And how do you know you're maintaining it over time? Eventually, once you've been on the plan for long enough, you'll begin feeling the difference between optimal and suboptimal metabolic function. It will almost become intuitive. For most though utilising ketone test strips is key to understand if you are in ketosis. You can test via urine, breath or blood testing - although many say that blood is the most efficacious method. 

Some people may find that getting into ketosis initially has some unpleasant side effects, such as the Keto Flu. However, this is something that can be avoided with the right hydration and electrolytes. 

Let's go over the various ketosis symptoms you might experience as you transition into this diet and discuss the value of using a ketone meter regularly to track your progress.

Getting Into Ketosis

Ketosis symptoms: Self-monitoring equipment of blood glucose and ketones level

The path to success on the keto diet is reaching and staying in a state of nutritional ketosis. This means that your body's primary energy source is ketones, from fat (dietary or stored body fat).

The ketogenic diet is a low-carb, moderate-protein, high-fat diet (sometimes referred to as ‘LCHF’ — low-carb high-fat — in the literature). To reach ketosis, you need to deplete your glycogen stores by reducing your carbohydrate intake to no more than 20 grams per day (for some they may be able to sustain ketosis on a higher level of carbs once fat adapted)  and replacing those calories with healthy fats. 

Healthy fats include avocados, avocado oil, coconut oil, coconut oil-derived MCT oil (medium-chain triglycerides), high-quality grass-fed and pastured dairy, and animal fats like lard, tallow and schmaltz. Dairy needs to be low- to no-lactose, such as dry cheeses, double cream, butter and ghee to avoid accidental sugar intake.

The excess fat and weight loss benefits begin when your body makes the switch from burning glucose to burning your body fat for fuel, so eventually, your total calorie consumption will need to go down a bit, but for now, just stick to making the swap. Your first goal is to switch your fuel source from glucose to fat. Your next step will be excess fat loss. You can also get personalised tailored macros specific to you, which can help with your goals (i.e weight loss).

Keto Flu and Ketosis Symptoms

Ketosis symptoms: Stressed woman slumping on the table with cups of coffee and laptop

Once you've begun making these changes in your diet, you might notice a few unpleasant side effects. Many people transitioning into keto will experience keto flu symptoms in the first week or two of the lifestyle change. These symptoms may include [3][4]:

  • Headache
  • Fatigue and difficulty exercising
  • Nausea and vomiting
  • Constipation or diarrhea
  • Dizziness
  • Sleeplessness
  • Muscle cramps
  • Bad breath or fruity breath
  • Dehydration

While these ketosis symptoms don't affect everyone, rest assured that if you experience any of them, they're just short-term symptoms that will go away after about a week of changing your lifestyle. You can also help avoid these symptoms too. 

To reduce the experience of these symptoms, hydration & electrolytes is key. Drink plenty of water and add sugar-free electrolytes to your water bottle. Also do not be afraid of adding salt to your foods. 

If you've never done a lifestyle like this before, you might also consider starting off gradually. Start with a more moderate low-carb diet the first week, then transition into true keto (less than 20 grams of carbs) to give your body a chance to acclimate [5].

Measuring Ketone Levels

Ketosis symptoms: Strip of pH paper on specimen cup with comparison chart

The best way to ensure that you're in the metabolic state of ketosis is to measure it. There are a few ways to measure the levels of ketones in your body: a ketone blood meter, a breath test device and urine test strips. 

Ketone Blood Meter

The most accurate way to test your ketone levels is through your blood. Blood ketone levels can be tested through an at-home device that pricks your finger the same way a diabetic patient would test his or her insulin levels with a finger prick [6]. 

These tests measure plasma acetoacetate and beta-hydroxybutyrate to determine your metabolic status. Unfortunately, the blood strips needed for this device are expensive, and you want to test regularly to ensure that you're on the right track, so this might not be the best solution for everyone. 

Breath Test Device

Breath testing measures the level of acetone (another type of ketone body) in your exhaled breath. These machines range anywhere from £25 all the way to £210 and are a great directional tool. 

Urine Test Strips

The third and most commonly used option is urine testing strips, which are as easy to use as a home pregnancy test. This testing method measures acetoacetate levels in your urine and provides a color chart with the package to help you understand your level of ketosis. Ascensia Ketostix Reagent Strips are a popular and inexpensive option available on Amazon for only £5.99. 

They are however not as efficacious as directly testing bloog but they could be used as a directional tool. 

Ketosis vs. Ketoacidosis

Doctor measuring blood sugar level of a patient

Ketosis is often confused with ketoacidosis, but they are completely different. Simply put, ketosis is your goal: a good and healthy way to turn your body into a fat-burning machine through the keto lifestyle. Ketoacidosis is a dangerous and deadly complication of both Type 1 diabetes and Type 2 diabetes, although it's more common in the former. 

Also called diabetic ketoacidosis (DKA), it's a serious, life-threatening condition in which your blood becomes highly acidic due to an overload of ketones. This happens because of inadequate insulin production, a hallmark of Type 1 diabetes, and not because of the keto diet [7]. 

The testing methods we mentioned above also function as ways for individuals with diabetes to monitor their blood ketone levels, but that's where the similarity ends. 

Your Path To Keto Success

People eating in blue tops

Eating keto is an incredibly effective way to help you shed body fat, improve mental clarity and reduce inflammation in your brain and body. Ketosis symptoms range as you transition from burning glucose to burning fat, but take comfort in knowing that these symptoms won't last long and can be mitigated by staying adequately hydrated and utilising electrolytes.

This way of eating has grown in popularity, in part because you can eat enough fat to avoid feeling hungry all the time, but also because testing for success is relatively easy and quick. Using keto strips or other forms of ketone testing like blood tests and breath tests will help you learn which foods kick you out of ketosis and which ones help you maintain adequate ketone levels. By testing regularly, you'll be able to track your progress and keep yourself in line over time, thus maximising the effects of this powerful lifestyle change. 

Head over to our keto recipes page to find some delicious ways to stay on track at every meal. If you’re worried you’ll be missing out on bread when you transition to keto, check out this 90-second keto bread recipe to start. And for even more support to get started, you can find our 3-Day Keto Meal Plan here.

All information provided on our website and within our articles is simply information, opinion, anecdotal thoughts and experiences to provide you with the tools to thrive.

It is not intended to treat or diagnose symptoms and is definitely not intended to be misconstrued for medical advice. We always advise you seek the advice of a trained professional when implementing any changes to your lifestyle and dietary habits.

We do however recommend seeking the services of a trained professional who questions the conventional wisdom to enable you to become the best version of yourself. 









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