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Find Out How Much Sugar Will Kick You Out Of Ketosis?

Being quite the self-experimenter, I've always wondered how many carbs I could eat and still maintain a state of ketosis. If you're anything like me you're probably also wondering how much sugar will kick you out of ketosis?

The amount of sugar that can disrupt ketosis will vary from person to person, but generally, even small amounts of sugar can potentially kick you out of ketosis. It's advisable to minimize sugar intake and stick to a low-carbohydrate, high-fat ketogenic diet to maintain a state of ketosis.

In this article, I'll go over how to find your keto carb limit, things that may knock you out of ketosis, symptoms you've been knocked out, and how long it will take to get back into ketosis.

How much sugar will kick you out of ketosis

How Many Carbs Can You Eat And Stay In Ketosis?

I get it. You want to know how many carbs you can get away with and still stay in ketosis. How do I know? Because I had the same question.

 The truth is, it's not as black and white as me giving you an exact number since the amount varies widely. 

As a general rule of thumb, I like to start people off with limiting their carb intake to no more than 30 TOTAL carbohydrates, but that's just me.

First, let's differentiate a carbohydrate versus sugar. In the most basic of senses, every carbohydrate you consume will break down into glucose (sugar). 

Carbohydrates and sugar in ketosis

Therefore, how many grams of sugar you can have in a day on a keto diet is the same as asking how many carbohydrates can you have. Meaning, if you stay under your carbohydrate limit and want to know what happens if you have table sugar or candy on keto, nothing will happen.

In theory, you shouldn't be kicked out of ketosis.

For your body to start creating a significant number of ketones, your body must first begin to empty its liver glycogen (sugar). On average, it will take ~28 hours of carbohydrate restriction for liver glycogen to become depleted.1 

The average adult stores between 80 and 100 grams of carbohydrates in the liver as sort of a “reserve” for bodily functions, including the central nervous system and the brain. Once this reserve depletes, the body begins to create ketones to help fuel the brain.

Now, how much sugar will kick you out of ketosis is dependent on how many carbohydrates you can eat without refilling liver glycogen. Once liver glycogen fills, the body no longer needs to create ketones.

 This refilling of the livers glycogen is what halts ketone production, hence kicking you out of ketosis. 

Things That Knock You Out Of Ketosis

As I've gone over in the previous section, the main factor that will knock you out of ketosis is the over-consumption of carbohydrates (sugar). Two significant factors help influence how many carbs it takes to knock you out of ketosis:

  1. How active you are
  2. How much muscle you carry

Meaning, the more muscle and more active you are, the more carbohydrates you can generally eat while staying in ketosis. For most individuals, between 20 and 50 grams of net carbs works to establish and remain in ketosis. 

However, I've known athletes and very active individuals who can eat upwards of ~150 grams of carbohydrates and still stay in ketosis. 

what to eat before a high intensity run on keto

Things That WON’T Knock You Out Of Ketosis

I've been around the space long enough to read all the myths about what will kick you out of ketosis, and most of them are just plain wrong. Some of the biggest myths about what will kick you out of ketosis are:

Eating too much protein

There's this thought that overeating protein will result in the protein magically turning into sugar and spiking your insulin. While marginally true, this couldn't be further from the truth.

Throughout the day, your body is converting non-carbohydrate substrates (fat, proteins, lactate) into glucose through a process called gluconeogenesis. This process is happening continuously, even daily, and while on a ketogenic diet. 

Gluconeogenesis is a demand-driven process. Meaning it only occurs when the body needs glucose. While the brain can run efficiently on ketones, it will always require a small portion of glucose to function. 

It's almost impossible for the average person to overeat protein where it would prevent them from entering a state of ketosis.

 A high protein intake may prevent you from seeing HIGH levels of ketones, but it shouldn't prevent you from entering and staying in ketosis.  

In fact, you can eat a diet void of carbohydrates and fat while consuming nothing but protein, such as a protein-sparing modified fast, and enter a state of ketosis. 

When it comes to protein, it's better to eat too much than too little. 

Artificial sweeteners 

Whether you're choosing to indulge in some sugar-free jello or your favorite stevia-sweetened product, artificial sweeteners shouldn't knock you out of ketosis.

As you know, by now, you must over-consume carbohydrates and refill liver glycogen to knock yourself out of ketosis. By nature, artificial sweeteners are virtually calorie-free, meaning it would be nearly impossible to knock you out of ketosis. 

While I'm not recommending this, you can chug a 2 liter of Diet Coke, and it should not affect ketosis. If you want to satisfy your sweet tooth with a diet soda or low-calorie sugar-free treat like sugar-free jello, be my guest.

Symptoms Of Getting Knocked Out Of Ketosis

Say you did overeat carbs (sugar) and do get knocked out of ketosis, how would you know?

While the only way to REALLY know if you've been kicked out of ketosis is to measure your ketones with ketone test strips, a blood ketone meter, or a ketone breath meter, there are a few signs you may have briefly exited ketosis. 

A sudden increase in hunger

Most people seem to experience a decrease in appetite or claim to not be hungry on keto, even while dieting. If you've experienced a sudden increase in your appetite after having a few carbohydrates, that may be a sign you're no longer in ketosis.

Decreased focus

A lot of individuals utilize a ketogenic diet due to the increased focus and mental clarity they experience. If you've noticed a sudden occurrence of brain fog or a hard time concentrating, this may be another symptom of being temporarily knocked out of ketosis.

Low energy

Are you feeling tired and exhausted on keto? Assuming you're not starving yourself or had a bad night of sleep, people report having plenty of steady energy.   

How Long To Get Back Into Ketosis When Kicked Out?

While you don't need to be in a state of ketosis to lose weight, being in ketosis has a wide array of benefits that help people adhere to their diets:

  • Increased focus
  • Decreased hunger
  • Stable energy levels

First and foremost, if you want to lose weight, you must be in a caloric deficit. You must be eating fewer calories than you burn per day. If you have no idea how many calories you should be eating, you can use the keto macro calculator to get a starting point. 

Let's say you do get knocked out of ketosis, how long will it take to get back in? Chances are if you've only had a few more carbohydrates than usual, you may exit ketosis for a brief period before finding yourself back in. 

However, if you decided to have a cheat day on keto or to come from a prolonged period of eating carbohydrates, it should take you between 24 and 72 hours to re-enter back into ketosis. The longer you've been in ketosis, the easier it seems to be to re-enter if knocked out.

I did an entire self-experiment to see how long it would take me to get back into ketosis after eating a carbohydrate-based diet for a few months. 

Here are three things you can do to help expedite the process if you wanted:

  1. Fast or intermittent fasting
  2. Light to moderate intensity cardio and weight training
  3. Reduce carbohydrates more than usual

There's no need to compensate if you fell off the wagon for a bit. Simply continue your ketogenic diet as usual and get back on track.

It's what you consistently do over time that will yield you the results you seek.

The Takeaway

Sugar should be treated like any other carbohydrate when it comes to how much sugar will kick you out of ketosis. If you are staying under 20 grams of net carbs, then you could mostly fill those 20 grams with pure sugar and still maintain a state of ketosis. 

I've found that how many carbohydrates you can eat while staying in ketosis will depend highly on how active you are and how much muscle you carry.

While you shouldn't make it a point to consume all of your carbohydrates from pure sugar, doing so once in a while shouldn't have any detriment to your fat loss efforts so long as you control your overall calorie intake. 

Frequently Asked Questions

Does any amount of sugar break ketosis?

No! The amount of sugar that you can consume depends on your carbohydrate limit. For some people the limit will be around 20-30g of carbs.

What are some sugar alternatives that you can use?

Instead of eating sugar on the keto diet, it's better to go with an alternative like allulose.

Can you do keto 5 days on 2 days off?

Yes! In theory you can follow any form of keto cycling. Every one is different, so each person will work best with a different cycle.


Founder of The Art Of Keto.

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