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How Long Does It Take To Get Into Ketosis Safely?

If you're just starting out on your ketogenic diet journey, you may be wondering how long it takes to get into ketosis. It's a great question, considering the journey to reach this optimal metabolic function and flexibility can be a bit unpleasant for some (although not all). Ever heard of keto flu? Of course, you'll find that this adjustment period is totally worth it and can also be overcome if you do some research and utilise plenty of electrolytes!

Once you've reached ketosis and experienced the benefits of burning fat for fuel instead of glucose, the research will have been worth it. 

Let's go over the basics first: the benefits of the keto diet and reaching a state of ketosis. Then we'll cover how long it takes to reach ketosis and discover ways to stay there as easily as possible.  

Defining the Keto Diet

Types of cheese

The ketogenic diet is a low-carb, moderate-protein, high-fat diet designed to raise blood ketone levels and transform your body into a fat-burning machine - also known as "fat-adapted" or in "ketosis". 

Keto dieters focus their food intake around healthy fats like coconut oil and MCT oil (medium-chain triglycerides, usually derived from coconut oil), avocado oil and high quality animal fats like lard, tallow and schmaltz. Acceptable dairy products on this diet include double cream, butter, ghee, full-fat cheeses and full-fat yoghurt (must be low- to no-lactose). Ideally, the animal products will be sourced from grass-fed or pastured animals to avoid the consumption of agrichemicals and to increase beneficial fatty acids like omega-3s. 

Some say it's important on this diet to eat green leafy veg in order to maintain healthy digestion and keep net carbs low. Net carbs are your total carbs minus fibre (here in the UK, carbs are already shown separately to fibre on labels). To enter ketosis, keep your carb count lower than 20 grams per day and invest in a blood ketone meter, keto breath meter, or ketone test strips to monitor your progress daily. We personally prefer a blood ketone monitor as it is believed to be the most efficacious. 

Health Benefits of Ketosis

how long does it take to get into ketosis: Woman lifting weights at the gym

The beneficial mechanism of the ketogenic diet is reaching a state of ketosis — when your body uses fat-derived ketones for fuel instead of glycogen. 

When eating a regular, non-keto diet, your body and brain run on glycogen, which is made from the glucose found in carbohydrate-rich foods. On a diet consisting of high carb intake, your blood sugar levels rise and fall with every meal. These changes in blood sugar can lead to cravings, feelings of lethargy (sugar crashes) and getting "hangry" between meals. They're also not great for weight loss or extra fat loss due to the spike of insulin levels after a meal.

By switching to the ketogenic diet, you stabilise your blood sugar, drain your glycogen stores and force your body into burning a new fuel source: ketone bodies. This new metabolic state turbocharges fat loss, preserves lean muscle mass, increases your mental clarity and energy levels and reduces inflammation in your brain [1]. 

In fact, the ketogenic diet was initially developed as a therapeutic tool for its anti-inflammatory properties to help treat epilepsy in children. The weight loss and performance benefits were happy side effects, which have made keto such a popular diet today. The positive side effects were seen as far back as the 1800s with the likes of William Banting popularising it.

What About the Keto Flu?

The keto flu is a cluster of potentially unpleasant side effects you may experience when transitioning from burning glycogen to burning ketones. It's named as such because the symptoms feel a bit like the flu: headache, lack of energy, brain fog, nausea, dizziness and slight muscle ache. 

These symptoms are temporary and can also be totally avoided if you utilise electrolytes and ensure you drink enough water. 

Part of the transition to a low-carbohydrate diet is a decrease in water retention that could lead to dehydration and an imbalance of electrolytes. This imbalance could be at least partially to blame for keto flu symptoms, so it's really important to stay hydrated and increase your sodium/salt intake during your transition [2].

How Long Does It Take To Get Into Ketosis?

How long does it take to get into ketosis? Woman running outdoors

Generally speaking, the time it takes can range anywhere from four days to two weeks. How long it will take to get into ketosis is individual to you. Strict adherence to the keto diet, activity level, sleep and stress levels and your body's natural metabolism will all affect how long it takes you to get into ketosis. 

If you want to speed up the process, you have four potential avenues:

  • A super strict version of the keto diet (<20g carbs)
  • Intermittent fasting
  • Extra exercise
  • Exogenous ketone supplements (see next section for more info)

A super strict keto diet involves emphasising healthy fat intake and keeping your carbohydrate intake as low as possible (<20 grams). Intermittent fasting, a schedule of eating that involves relegating your calorie intake to a small window of time every day (such as 8 hours) and fasting for the remaining hours will help your body use up stored glycogen more quickly and pump up your ketone production. 

Adding in additional workouts will also help you burn up glycogen and produce more ketones naturally. Exogenous ketones are supplements you can take to add dietary ketones into your bloodstream. Beta-hydroxybutyrate and acetoacetate are ketone salts that you can purchase to help you reach ketosis more quickly and potentially ease the transition [3]. 

Do Exogenous Ketones Work?

The jury is still out on whether or not exogenous ketones are a good idea for weight loss. While some studies show that using exogenous ketones can act as an appetite suppressant, these effects are most notable when taken while fasting [4]. 

Endurance athletes may experience performance benefits when using exogenous ketones as an additional source of energy, but some studies suggest that exogenous ketones might actually be counterproductive for fat loss. 

That's because it's possible to have too much of a good thing. Too many ketones flooding your bloodstream can have harmful consequences, namely causing highly acidic blood. Your body has natural fail-safes in place to prevent this from happening, which results in a slow-down of ketone production and fat burn [5]. 

In other words, taking exogenous ketones could inhibit fat loss rather than accelerate it.

The jury is still out on these.

Don't Push It

It's important to ask yourself whether or not you actually want to reach ketosis as quickly as possible. For some keto dieters, rushing into ketosis has no negative side effects. They cut carbs, drop water weight and transition into burning body fat right away. 

For others, using extreme measures to reach ketosis can amplify the effects of the keto flu. This is especially true if you've never done a diet like this before or if you're not hydrating properly. Again, it's incredibly important to keep your electrolytes balanced as you transition into fat-burning mode. 

No matter which way you go, listen to your body and try not to force yourself into being intensely uncomfortable for too long for the sake of weight loss. 

Safely Reaching Ketosis Is Key To Keto Success

A couple smiling at the camera after exercising outdoors

The keto diet is designed to offer an improved quality of life, physically and mentally. If your goal is fat loss and ultimately being able to maintain a healthy weight in the long-term, try to view this meal plan as a lifestyle change. Getting into ketosis as quickly as possible should be less important than maintaining it once you get there. 

You don't want to overstress your body to reach ketosis only to crash and give up before you've even begun experiencing the health benefits. It's OK to experience slight discomfort, but if the transition has you laid out on the sofa for days, you might consider slowing down, drinking a sugar-free electrolyte drink and eating more often until the symptoms subside. How long it takes you to get into ketosis will be individual to you, so be patient with yourself, don't compare yourself to others and listen to your body.

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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