How Long Does it Take to Get Into Ketosis?

Whether you're a Keto novice or looking to get back on the low-carb wagon, you may have questions like, how long does it take to get into ketosis?

It depends. Your fat-burning (and ketone-producing) capacity depends on your biology, diet, exercise habits, genetics, and many other factors.

Even under the same conditions, two people will enter ketosis at different rates. But as you’ll learn, you can tweak those conditions to hasten your rate. 

If you're interested in entering ketosis faster, this article is for you.

What Is Ketosis?

Ketosis is a metabolic state defined by elevated blood ketone levels.[*] (Ketones are molecules that provide clean, efficient energy for your brain and body.) And how do you make ketones and enter ketosis? By burning fat in the liver. 

But fat-burning doesn’t happen randomly. It requires a signal, and that signal is low insulin.[*] 

Insulin is your master energy storage hormone. When insulin is high, you store energy. When insulin is low, you burn it.[*] 

You keep insulin low by minimizing dietary carbs and, to a lesser extent, protein. That’s why the Keto diet and intermittent fasting may help you burn fat. Both minimize carbs.  

Entering ketosis by restricting carbs is called nutritional ketosis. It’s the type of ketosis researched for its potential benefits like:

• Weight loss[*]
• Craving control[*]
• Improved energy level
• Clearer cognition (ketones fuel the brain)[*]
• Reduced inflammation[*]
• Lower blood sugar (type 2 diabetes reversal)[*]
• Improvements in certain cancers and Alzheimer’s disease[*][*] 

Let’s assume you want to capture these potential benefits. How do you know you’re in ketosis?

How To Know You’re In Ketosis

You can measure ketones in blood, urine, and breath. Blood ketones are the gold standard, and from 0.5 mmol/L to 3.0 mmol/L is generally considered the sweet spot for nutritional ketosis.[*] 

Don’t neglect subjective measures, though. Are you losing fat? Craving fewer snacks? Not feeling “hangry” on a 5 PM video call that’s bleeding into your weekend? It’s possible you’re in ketosis. 

How Long Does it Take to Get Into Ketosis?

There’s no stock answer to this question. You will enter ketosis when the conditions in your body permit. 

The primary condition is low insulin. If insulin is low, your liver will receive the fat-burning signal and start making ketones.[*] 

Insulin levels depend mainly on dietary factors. If you’re eating lots of carbs, insulin will stay high, and you won’t make ketones. But if you keep carbs below 5 to 10 percent of daily calories (the main rule of Keto dieting), your insulin should stay sufficiently suppressed for Keto magic. 

How long does it take to get into ketosis, though? That depends on your starting point. 

If you’re transitioning from a high-carb diet, it may take a week or more. Your cells don’t go from burning sugar to burning fat in the space of a finger snap. 

But what if you’re coming off a cheat day? How long does it take to get back into ketosis?

It depends on how many carbs you had, but maybe a day or less. Of course, the only way to be absolutely sure is to measure your ketones!

Why Some People Take Longer To Enter Ketosis

Some people enter ketosis more rapidly than others. An athlete might re-enter ketosis mere hours after a high-carb meal, while a person with type 2 diabetes might need days of low-carb dieting to enter fat-burning mode. 

It depends on how fat-adapted you are. If your body is used to running on sugar, it takes more time to transition to using fat for energy.[*] But if you’re Keto cycling (occasionally eating carbs), your return to ketosis will be swifter. 

5 Tips to Enter Ketosis Faster

Want to get into ketosis faster? Follow these five tips.

#1: Watch Your Carbs

Nothing derails ketosis faster than eating carbs. Carb restriction is critical to keep insulin low and burn more fat. 

Most Keto guidelines recommend keeping carbs below 10% of your daily calories.[*] Athletes can probably get away with more, but sedentary folks may need to tighten the limit. 

Be aware that hidden carbs are everywhere. You’ll find them in soups, sauces, fruits, starchy vegetables,and even mussels. 

Track carb intake by logging your meals in the Carb Manager app. You might be shocked by how many carbs are in your low-carb diet.

#2: Eat More Fat

Fat has the most negligible insulin impact of all the macronutrients. Consequently, fat will be your primary energy source on a ketogenic diet.[*] 

On Keto, opt for fatty cuts of meat and fish, and don’t be shy about adding olive oil, butter, or ghee to your low-carb veggies. Those healthy fats are helping you get into ketosis.  

#3: Try Intermittent Fasting

Intermittent fasting is the practice of taking regular breaks from calories. These breaks help you enter ketosis by keeping insulin low. 

For a potent fat-burning regimen, combine intermittent fasting with the Keto diet. It can be a great way to accelerate your fat adaptation. 

But listen to your body. If you feel weak or tired, expand your feeding window and reassess. 

Note: Intermittent fasting is not appropriate for everybody. Young individuals may find it very easy to skip a meal, but older people on multiple medications should consult with a doctor first. I.F. is also not a great fit for people who are pregnant, breast feeding, actively undergoing chemotherapy, or have a history of disordered eating.

#4: Exercise

When you exercise, you liberate (and burn) fatty acids for energy. As a result, you can enter post-exercise ketosis.[*] 

The most ketogenic exercise? Aerobic activity in the “fat-burning zone” of around 60-75% of max heart rate.[*] 

#5: Consider MCT Oil or Exogenous Ketones

MCT oil and exogenous ketones won’t make you fat-adapted, but they may increase your ketone levels. And higher ketone levels bring their own potential benefits, like improved cognition.[*] 

Think of these supplements as aides on your Keto journey. They won’t do the work for you, but they might make things easier. 

To enter nutritional ketosis, simply consume a well-formulated Keto diet. If you don’t enter ketosis overnight, don’t panic. You’ll get there eventually. 

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