When you fast, you are supposed to be in an even deeper state of ketosis. So if this does not happen after a fasting state, then it means that there is something you are doing wrong.

Consuming foods or drinks with added sugars such as lemonade can not only break your fast but also kick you out of ketosis.

This happens because your body does not have enough body or dietary fat to burn for energy. And since it cannot turn to glucose which is also not available, it will be in a state of energy limbo.

sad face drawn on a white plate with fork and knife

CAN FASTING TAKE YOU OUT OF KETOSIS?

Fasting is when you go for a period of time without food, either for a short term or for longer hours, depending on the type of fast. Fasting can help you get into ketosis faster. However, there are those who can achieve a state of ketosis in between meals.

it is important that you first get the green light from your healthcare provider before you embark on fasting while on keto, and must have been on this diet plan for more than two weeks at least. All in all, fasting is not supposed to take you out of ketosis.

HOW LONG DOES IT TAKE TO GO INTO KETOSIS WHEN FASTING?

Man holding a pocket watch

When you have an overnight fast, you can have the blood ketone levels get up to 0.1 mmol to about 0.5 mmol per liter. However, this is just below the standard ketosis threshold which requires ketone body concentrations to be anywhere between 0.6 mmol per liter and 1.5 mmol per liter.

If you fast for two days, that is 48 hours, you can increase the concentration of circulating ketones from about 1mmol per liter to 2mmol per liter.

However, if you decide to go on a long-term fast to try and be keto-adapted or just get into a state of ketosis first, it is always best if you first seek your doctor’s or any trusted health practitioner‘s guidance on the fast to ensure safety.

Also, it is in your best interest to first see how your body responds to a limited daily feeding window, or even a day’s fast that is a bit moderate, before going for something more extreme or bold.

Related post: How to stay in ketosis overnight

DOES INTERMITTENT FASTING INDUCE KETOSIS?

Intermittent fasting is a dietary approach to inducing or speeding up ketosis, and it involves having short-term fasts at stipulated regular intervals. You can choose to have prolonged food restrictions for a few days every week or monthly, or eat within an eight-hour period and then fast for the remaining sixteen hours.

The latter is better for ketosis. During that period that you are in a fasting state, the levels of blood glucose, insulin, and glycogen are being lowered hence promoting the production of ketones from fatty acids.

The science behind it is that when you are running low on blood glucose, your body will turn to your glycogen stores in the liver and muscles to burn and provide energy that it will run on. If those are not restored eventually, they will get depleted too and the next alternative is the fat.

The body’s fat cells release fats into the bloodstream and which go straight to the liver where they are converted to ketones, and those are then metabolized to act as an energy source for your body and brain.

WILL A 36-HOUR FAST PUT ME IN KETOSIS?

Your body can achieve a state of ketosis in as little as six to twelve hours if you are physically active, as your body will not be storing that much glycogen but will be working to deplete it.

However, you do not have to go into extended periods of fasting such as more than a day so as to get into ketosis. But if you choose to, you have to first seek your doctor’s opinion on the fast.

Even if you manage to get into ketosis in under a day or 36 hours, you will not be fully adapted in such a short amount of time. This is so as keto-adaptation takes a little bit longer, up to a month in some cases.

 

HOW DO YOU KNOW YOU ARE IN KETOSIS WHEN FASTING?

As the fats are being converted to ketones, they will build up in the blood and will be eliminated through the urine. For you to know that you have achieved ketosis while in a fastened state is to test your blood and urine for ketone levels. The number of ketones present also indicates how deep you are in ketosis with fasting.

The different types of ketones produced can be each measured using separate methods. Acetoacetate is measured through the urine and using a ketone urine stick or strip.

The strip will turn different shades of pink or purple based on the ketone levels in the urine. If the strip turns into lighter shades of pink or purple, then you will know that you are deep into the fasting as it will indicate a lower number of ketones leaving your body.

This is because when in a prolonged fastened state, the body burns stored body fat and not dietary fats and therefore cannot throw out a lot of the ketones that it metabolizes.Glucose Blood meter

 The beta-hydroxybutyrate on the other hand is measured through the blood and using the blood ketone meter.

When you have a blood ketone level of 0.5 mmol per liter and above, it shows that you are getting into ketosis, but if it is between 1.5 to 3.0 mmol per liter, then you are well deep in ketosis.



Additionally, if you are practicing intermittent fasting, you can experience keto flu symptoms and this is a good way to know that you are transitioning to ketosis.

Related post: WHY ARE MY KETO STRIPS NEGATIVE? (SOLVED)

HOW DO YOU MAINTAIN KETOSIS AFTER FASTING?

woman standing on a bathroom scale

There are foods to avoid and those to eat so as to maintain that metabolic state of ketosis after breaking a fast. The following are some of the food to avoid and why:

Foods that are a bit high in carbs or are processed. This is so as to avoid suddenly increasing your blood sugar which can be dangerous to you. According to research, constant sudden spikes in blood sugar can damage your blood capillaries and can be fatal.

Dairy with high lactose content. These include yogurt and milk. Lactose proves to be more troublesome following a long period of fasting. Therefore, you should eat products that are dairy-free such as almond milk, or even those with low lactose content such as butter, lactose-free milk, and hard cheeses which are keto-approved.

There are those foods that we highly recommend you eat to break the fast and which will ensure that your body does not get sent off ketosis.

Vegetables. Opt for the less-starchy and non-cruciferous vegetables. In addition, these should be cooked in healthy fats such as grass-fed butter, avocado oil, or sunflower oil. Your body is bound to be in ketosis after longer periods of fasting, therefore, these fats will serve to provide fuel.

In addition, when you choose to sauté them, it will help in breaking down the structural elements of the veggies, hence making them a little bit easier on your stomach, as they will be easy to digest.

Avocado. In addition to the high fiber content that it has, it also has lots of healthy fat that is beneficial for your fat-adapted body to use following your fast. These dietary fats aside from providing your keto-adapted body with a source of fuel, they will also serve to make you feel full.

CAN YOU HAVE KETO FLU WHILE FASTING?

When you choose to have intermittent fasts on keto, be ready to feel sick. This will however depend on the length of your intermittent fast. You can experience extreme tiredness, headaches, constipation, or a constant feeling of being cranky. If you want to decrease these keto flu symptoms, you can switch to a periodic fast.

WHAT CAN I CONSUME WHILE FASTING ON KETO?

Bone broth
Bone broth

The following are some of the things that are safe to consume while fasting on keto. However, they should be taken in small portions. Moreover, you should be wary of those containing calories as they will break your fast, and if you were not seeking to do that, then avoid them completely.

Water. Whether plain or carbonated, water does not contain any calories and so will not break your fast. Also, it will help you stay hydrated during a fast.

Coffee and tea. These should be taken without adding any sugars or milk and cream. However, there are those who report adding some amounts of fat or non-dairy milk helps them reduce hunger pangs.

In addition, there are those who drink their coffee with added MCT oil, coconut oil, butter, or ghee while fasting. You should however keep in mind that oil happens to break one’s fast because they contain calories, but it will not kick you out of ketosis as it provides that energy source for your body to remain in that metabolic state.

Bone broth. This is not only rich in nutrients but can also help you replace the electrolytes that you are losing while only drinking water, especially during long periods of fasting. However, beware to consume this in small quantities as it contains calories. This also means that it will break your fast.

Diluted apple cider vinegar. For some, having one or two teaspoons of apple cider vinegar added to their water helps them in periods of fasting by preventing them from becoming dehydrated and keeping cravings at bay.

 

CAN I DRINK COKE ZERO WHILE FASTING?

Coke Zero has zero calories and will not kick you out of ketosis. However, it is not advisable as frequently taking it- in a fasting state or not, will lead to adverse health effects eventually. This is why we recommend you just take plain or carbonated water in periods of fasting and fasting windows to quench your thirst.

CAN I HAVE DIET COKE WHILE FASTING?

You are probably thinking that because calories are the only thing that will break your fast, so diet sodas are safe because they have zero to low calories. You are wrong. There are other ingredients in diet cokes that will sabotage your fasting goals such as artificial sweeteners.

Furthermore, artificial sweeteners can lead to weight gain or derail your weight loss efforts. And one of the reasons you are on keto is probably to lose weight so why risk tampering with your goals?

DOES WATER WITH LEMON BREAK YOUR FAST?

Plain lemon water will not break your fast, and so is diet lemonade so long as it has low amounts of calories. However, lemon water with added sugars such as lemonade will break your fast, and even kick your body out of ketosis. This is attributed to the sugar content that is not needed while fasting.

HOW MANY CALORIES WILL BREAK A FAST?

The general rule of thumb is that for you to remain in a fasted state, you should have a minimum of 50 calories during each of the fasting windows. Therefore, if you exceed this amount then you will definitely break your fast.

Related Post: HOW LONG DOES IT TAKE TO GET BACK INTO KETOSIS AFTER A CHEAT MEAL?


SUMMARY

Yes, you can achieve nutritional ketosis simply by strictly following the ketogenic diet, that is, having foods that are low in carbs, moderate in proteins, and high in fat and eating within your set daily macros split. The keto diet has been known to increase the concentration of circulating ketones by up to four times.

However, when you throw fasting into the mix, your body’s ketone concentrations can increase by up to twenty times. Therefore, fasting also has a more beneficial effect on overall health when paired up with the keto diet.

Furthermore, it is best to ease back into your diet after fasting with foods that are easy to digest and which contain adequate amounts of healthy fats. Choosing to have a cheat meal after breaking a fast is not a smart move, as this will only derail your efforts and kick your body out of ketosis.

Lastly, when fasting on keto, be sure to avoid keto-approved foods that can break your fast and even probably kick you out of ketosis. Foods with a high-calorie content of over 50 calories can break your fast.