As it is a staple of so many lives, coffee during intermittent fasting raises many questions, which are answered here: ✅ milk ✅ cream ✅ sweetener and more!
Can you drink coffee while intermittent fasting?
That‘s probably one of the most frequently asked questions about intermittent fasting. But if you are just starting with intermittent fasting, don’t worry too much about it.
Because by deciding to promote your health through intermittent fasting, you already belong to the caring top 5% of humanity.
Moreover, you will learn some tips in the course of the article, which will make intermittent fasting easier for you.
Intermittent Fasting and Coffee
To answer the question of whether you are allowed to drink coffee during intermittent fasting, we must first look at the effects of coffee on intermittent fasting and its benefits.
Coffee and Autophagy
Every engine, no matter how good, must be maintained and regularly serviced. The same applies to your body. Fortunately, nature has already provided for this.
Fasting induces autophagy, a natural cleansing mechanism that replaces broken cells with new ones and drains toxins from your body.
Accordingly, autophagy is one of the most significant health benefits of fasting. Therefore, the discovery of autophagy was awarded the Nobel Prize for Medicine in 2016 (Levine et al. 20171).
Furthermore, it can slow down the aging process (Gelino et al. 20122).
Fasting is one of the best ways to activate autophagy (Bagherniya et al. 20183).
Coffee also helps to activate autophagy. So you can increase the benefits of fasting with coffee (Pietrocola et al. 20144).
Coffee and Weight Loss
Coffee drinkers are maintaining their weight over the long term more efficiently (Icken et al. 20175).
The fact that coffee reduces appetite could be a good reason for this (Greenberg et al. 20126).
Also, coffee increases the metabolic rate. Hence, coffee is particularly beneficial for weight loss (Acheson et al. 19807).
Therefore, the combination of coffee and intermittent fasting can help you to stay fasted longer and lose weight quicker.
Coffee and Ketosis
If you don’t eat, your body uses up its carbohydrate stores and then begins to burn body fat for energy.
Since your body delivers fat energy to all corners of the body as ketones, this state of fat burning is called ketosis.
Thus, fasting is an easy way to get into ketosis faster.
Therefore, you can easily combine intermittent fasting with a ketogenic diet. In short, the keto diet tries nothing else but to achieve a state similar to fasting and its benefits through diet.
Accordingly, fasting helps enormously with the keto diet. But drinking coffee while intermittent fasting can give fat burning an even bigger boost.
Because according to recent research, coffee gives an additional boost to ketosis during fasting (Vandenberghe et al. 20178).
As with the ketogenic diet, elevated insulin levels are a problem with fasting. Since the storage hormone triggers the switch back from fat burning to fat storage, it is better kept low.
Moreover, it suppresses the fat breakdown enzyme in the human body (Meijssen et al. 20019).
Coffee and Insulin Sensitivity
In the long run, fasting is one oft he most effective methods to improve insulin sensitivity and, thus, glucose metabolism. Therefore, intermittent fasting helps to prevent diabetes.
Nevertheless, fasting can reduce insulin sensitivity in the short term. Since this reaction has an excellent reason, it is harmless.
Because the body ensures that the majority of glucose available is delivered to the brain, some other cells become acutely insulin-resistant. For this reason, those parts of the brain that cannot run on ketones and need glucose can get enough of it.
But don’t panic as the liver synthesizes sufficient glucose from amino and fatty acids during fasting (Merimee et al. 197410).
Coffee has a similar effect. Acutely, coffee reduces insulin sensitivity and glucose tolerance. Therefore, you should never add sugar to coffee or eat cake with it.
However, coffee improves insulin sensitivity and glucose metabolism in the long term. For this reason, recent studies show that coffee reduces the risk of type 2 diabetes (Carlström et al. 201811).
Can You Drink Coffee While Intermittent Fasting?
A cup of black coffee contains 1-4 calories and minimal amounts of protein, fat, and trace elements. The same applies to decaffeinated coffee.
For most people, the nutrients in 1-2 cups of black coffee are not enough to influence their metabolism to break the fast (van Dam et al. 200412).
Since coffee can help suppress appetite, it helps many people to extend fasting periods.
However, enormous quantities of coffee can undoubtedly influence intermittent fasting. Since coffee stimulates the hormone adrenaline, it can trigger energy release, such as while experiencing acute stress (Smits et al. 198613).
For this reason, glucose can indirectly enter the bloodstream even without food intake (Sherwin et al. 198414).
As long as you do not drink more than 1-2 cups in a short time frame, coffee will not significantly affect intermittent fasting.
Nevertheless, it can become more critical during prolonged fasting (24+ hours). Although there can be no generic answer here, I would not drink more than 5 cups of coffee.
And these should be spread throughout the day. That way, you are on the safe side. Rough amounts such as 10 cups a day can definitely influence fasting.
With 16/8 intermittent fasting, you can safely drink 2-3 cups before lunch.
But what about creamer and other popular additives in your coffee?
Can I Have Cream in My Coffee While Intermittent Fasting?
100g heavy cream contains about 3g milk sugar (lactose) and milk protein. Although some heavy cream does not necessarily inhibit fat burning, it will negatively affect autophagy.
Thus cream breaks a fast. However, that doesn’t mean that a splash of cream destroys all the benefits. Fasting benefits such as autophagy do not have a binary switch. Nevertheless, heavy cream will inhibit results.
Nonetheless, heavy cream can be a welcome ingredient in a ketogenic diet since it helps to promote autophagy in the long run.
Intermittent Fasting: Coffee With Creamer
Creamer and similar additives in powder form are highly processed. Therefore, these are absolute junk!
They are loaded with carbohydrates, proteins, and fat. Moreover, some creamers consist of up to 50% sugar.
Also, coffee with sugar-free creamer isn’t an option. Besides too much protein and fat, you will find other artificial additives like sweeteners in it.
If you like your body, you should avoid these junk additives not only during fasting.
Intermittent Fasting: Coffee With Milk
100ml of milk not only contains almost 5g of lactose but also approximately as many milk proteins.
The calculation here is simple. With intermittent fasting, milk makes the difference in coffee. Even a dash of milk detracts from the benefits of fasting.
Coffee with milk breaks the fast.
What about skimmed milk?
Intermittent Fasting: Coffee With Skim Milk
Even with milk, the low-fat variant makes everything worse. As with other low-fat products, more sugar is hidden in skim milk. And of course less fat to counteract it.
In short, with skimmed milk, blood sugar and insulin levels rise even faster. That’s why muesli with milk, for example, is one of the worst meals for your health – not only when you’re on a ketogenic diet.
Also, skimmed milk is out. What about half and half?
Intermittent Fasting: Coffee With Half and Half
Since cream and regular milk can break a fast, half and half can too. Due to the significant mix of protein and carbs, half and half inhibits fasting benefits.
Furthermore, half and half is more likely to contain processed additives.
So regular kinds of milk are not safe for fasting. Can coffee with almond milk be an alternative for intermittent fasting?
Intermittent Fasting: Coffee With Almond Milk
Small amounts of almond milk are in the grey zone while intermittent fasting.
As long as you avoid the sweetened or protein-enriched versions, and only add a shot, the effects of almond milk in coffee are negligible.
Nevertheless, almond milk technically breaks the fast. Therefore pure nut milk is not suitable as a drink during fasting.
Intermittent Fasting: Coffee With Oat Milk
Since the food industry jumped on the vegan hype train, oat milk is currently enjoying great popularity.
But have you ever thought about the fact that it might be unnatural to make a milk substitute from grains? Where does the fat content come from, which you need for creaminess?
As I suspected, the fat in popular brands comes from industrially processed vegetable oils, such as canola oil.
To produce oil artificially from a non-oily plant is not only unnatural but also harms your health significantly.
Since chemical processing damages highly sensitive omega-6 fatty acids, they promote free radicals in your body.
Accordingly, your body should probably not use these broken fats as essential building blocks of your brain cells. Don’t you think so?
Hence, for people who are intermittent fasting for health reasons, oat milk is not an option.
So, what about weight loss?
Besides the 7.5 grams of fat from canola oil, a glass of oat milk has a staggering 16.5 grams of carbohydrates, of which 10 grams are table sugar (*).
Thus, we no longer need to debate. That’s the last nail in the coffin for oat milk during intermittent fasting.
Since even a shot of oat milk triggers a blood sugar and insulin spike, you better put it into the sink.
Intermittent Fasting: Coffee With Soy Milk
So, is soy milk another supposedly better alternative to milk while fasting?
One glass of soy milk has about 15.5 grams of carbohydrates, of which 10 grams are table sugar (*).
As with oat milk, industrially produced omega-6 fatty acids predominate in this artificial drink.
Furthermore, the soy itself is one of the three most frequently genetically manipulated plants in the world. Accordingly, over 90% of the canola, corn, and soy harvest comes from genetically manipulated plants.
Why should your soy drink be non-GMO?
On the one hand, this almost impossible to find out, and on the other hand, it is highly unlikely.
Since the soy probably comes mostly from a foreign country, the first processing steps happen somewhere, neither traceable nor regulated.
So what’s the solution?
Eat real food! Industrially produced drinks from mixed in a lab are harmful to your health – no matter what the ads are promising.
However, a single shot of soy milk breaks the fast due to the high amount of carbohydrates.
With this in mind, if you need a milk substitute while eating due to an intolerance –better use unsweetened almond milk.
Intermittent Fasting: Coffee With Cocoa
Although a little cocoa powder is fine, you should pay attention to the amount.
Since the cocoa powder is made from the whole cocoa bean, it contains carbohydrates, protein, and fat. Therefore, more than a teaspoon of cocoa powder will break the fast.
There are two things to pay attention to with cocoa powder:
- It must be unsweetened
- Ideally, it is degreased too
Intermittent Fasting: Coffee With Cinnamon
Cinnamon is okay as an addition. Moreover, it is a proven remedy against appetite and cravings. Therefore, it is welcome in our coffee during intermittent fasting.
Furthermore, cinnamon can even help to reduce insulin resistance. For example, the one you get after lack of sleep.
Intermittent Fasting: Coffee With Nutmeg
Just like cinnamon, a little nutmeg can help against an acute appetite. Nevertheless, avoid excessive amounts as they can cause side effects.
Bulletproof Coffee and Intermittent Fasting
The essential aspect of every Bulletproof Coffee is the addition of high-quality fat. Hence, Bulletproof Coffee is not an ordinary coffee with cream.
It is a keto-friendly coffee drink that is also popular with intermittent fasting enthusiasts.
Also, many athletes or professional high performers drink Bulletproof Coffee. They all swear on Bulletproof Coffee to get an energy boost from quickly metabolized fat.
For this reason, they leverage Bulletproof Coffee to complete tasks more efficiently and faster. Since this power drink helps you keep saturated, awake, and concentrated, it is a keto and intermittent fasting staple.
The classic Bulletproof Coffee recipe contains two essential ingredients besides black coffee:
- Quickly metabolizable MCT or coconut oil
- High-quality grass-fed butter or ghee
Coffee With MCT Oil
MCT stands for “medium-chain triglycerides”, medium-chain fatty acids.
Since it is derived from the latter but contains a far higher concentration of MCTs, MCT oil is virtually the powerful brother of coconut oil.
Since MCT oils can consist of caprylic acid (C8), which is only eight carbon atoms long, they can be metabolized quicker than coconut oil.
Does coffee with MCT Oil, a pure fat, break a fast?
Although pure fats usually have many calories, they do not affect blood sugar. Nevertheless, it is virtually a meal. And eating simply affects insulin levels.
In the case of pure fat, however, this happens only indirectly and minimally.
Technically speaking, any fat breaks a fast. Therefore, you will burn less fat due to Bulletproof Coffee during intermittent fasting. Nevertheless, the impairment is only minimal.
Coffee With Coconut Oil
For the same reason, coffee with coconut oil is particularly suitable for fasting beginners. This way, you can counteract hunger and get used to intermittent fasting.
If you can fast only 12 hours on black coffee when starting but can extend to 16 or 24 hours using a few teaspoons of coconut oil, the disadvantages of adding fat are acceptable.
Nevertheless, you will not need fat after a few days of practice to prolong intermittent fasting.
Coffee With Butter or Ghee
Grass-fed butter gives classic Bulletproof Coffee a creamy consistency. It also contains high-quality fats that increase satiety and energy level.
Furthermore, grass-fed butter provides powerful nutrients such as vitamin A, beta-carotene, butyrates, or conjugated linoleic acid.
If you are looking for an allergy-friendly, shelf-stable option with almost no lactose, grass-fed ghee is your answer.
Butter, like coconut oil, breaks the fast, but should not significantly affect autophagy.
Although the intake of proteins interrupts this self-cleaning mechanism of the body, the amount in butter is negligible.
Ghee is even safer, as it is ultra-clarified butter without any milk sugar and protein.
Coffee With Collagen or Whey Protein
The athletes among the intermittent fasting and keto enthusiasts love collagen in their Bulletproof Coffee.
Nevertheless, like whey powder, it is pure protein. On the one hand, protein activates the anabolic mTOR pathway for muscle building. On the other hand, it inhibits autophagy.
Therefore collagen can have advantages for muscle building, fat burning, and satiation but breaks a fast.
Fasting and Artificial Sweeteners
Sweet taste is a much-discussed topic regarding intermittent fasting and the keto diet. On the one hand, it is difficult to get away from it. On the other hand, it substantially promotes cravings.
Most sugar-free sweeteners have zero protein, carbohydrates, and calories. Therefore, they do not raise the blood sugar level. But is the calculation that simple?
No, since people often forget that both intermittent fasting and keto have one essential goal: Lowering insulin levels to allow your body to tap into stored fat for energy.
Since the storage hormone, insulin, prevents body fat breakdown and ketone production, a significant increase in insulin levels breaks the fast.
Unfortunately, most diet gurus have not done their homework in this context.
As endocrinologist and fasting pioneer Dr. Jason Fung correctly points out, it does not matter whether food increases blood sugar levels as long as it increases insulin levels (Fung 201615).
Intermittent Fasting: Coffee With Sugar
Since sugar already increases blood sugar and, therefore, insulin levels, it’s off the table.
The high-calorie cocktail of glucose and fructose breaks every fast.
Intermittent Fasting: Coffee With Sweetener
The most common sweeteners are aspartame in Diet Coke, acesulfame-K in Coke Zero, and sucralose in Splenda.
None of them provide carbohydrates, proteins, or calories. Nevertheless, studies show that they increase insulin levels significantly.
For example, sucralose increases insulin levels by around 20 percent (Pepino et al. 201316).
While aspartame, the classic sweetener in diet soda, does not affect blood sugar, it can increase insulin levels more than regular sugar (Anton und Martin et al. 201017).
Moreover, the artificial sweetener acesulfame potassium in zero drinks increases insulin levels in the same fashion as glucose does (Liang et al. 198718).
Therefore, in addition to a variety of other side effects, these sweeteners prevent fat burning.
Hence, artificial sweeteners are no safe option during intermittent fasting.
Coffee With Xylitol
Xylitol is the most common sugar alcohol. However, it isn’t calorie-free.
Also, xylitol triggers a small but significant increase in blood sugar levels.
As this stimulates digestion, xylitol can break a fast (Natah et al. 199719).
In contrast, erythritol, another sugar alcohol, does not have this effect.
However, I would use this sweetener only occasionally, as it can cause addiction.
Both sugar alcohol sweeteners are marketed as natural sugar substitutes. Xylitol, the supposed birch sugar is usually not made from birch wood, but from straw or corncob remains
Also, erythritol is produced industrially from carbohydrates.
In the case of xylitol, the process uses acids or lyes. In the case of erythritol, the procedure uses microbial fermentation.
Coffee With Stevia
The often praised sweetener, stevia, also significantly increases insulin levels.
Since many diet gurus haven’t carefully read a well-spread study, the common opinion about stevia is often incorrect.
Because consuming a meal with stevia does not reduce the blood sugar and insulin response, as is often claimed.
Only in comparison to the same meal with table sugar, these reactions are sometimes minimally lower (Pepino et al. 201320).
“Natural” sweeteners such as stevia or agave syrup are processed industrially in the same way as table sugar. Also, the addictive white crystal comes from “natural” sugar beet.
Furthermore, agave syrup with up to 97% fructose content is diabetes in liquid form.
Although stevia may be acceptable for dessert on special occasions, it is not daily during fasting.
Coffee With Monk Fruit
Monk fruit extract has a similar effect to stevia. It is also extremely sweet – about 200 times sweeter than sugar.
Although monk fruit sweetener is one of the better alternatives, I wouldn’t use it daily for intermittent fasting, due to its counterintuitive nature.
According to studies, intense sweetness promotes appetite and cravings (Yang 201021).
You Can Drink Coffee While Intermittent Fasting
Coffee can help while intermittent fasting. As long as you pay attention to what you are adding, coffee doesn’t break intermittent fasting. On the contrary, coffee can even boost fasting benefits.
In the end, it’s up to you. If a cup of coffee takes away your hunger during fasting, gives you energy, and makes you feel good, go for it!
Nevertheless, you should avoid large quantities.
Also, you can drink black or green tea while intermittent fasting. But be aware that milk and other additives will have the same effects as with coffee.
Since they often contain candied fruit and other hidden sugars, I would pay close attention to the ingredients of herbal tea.
If this ultimate guide to intermittent fasting and coffee could help you, I would be happy if you share it with friends 📤
Intermittent Fasting Coffee FAQ
Does coffee break intermittent fasting?
No, black coffee ☕ doesn’t break intermittent fasting. But coffee with cream or milk 🥛 does.
Can I drink coffee on the 16 8 Diet?
On a 16/8 intermittent fasting schedule, you are allowed to drink black coffee ☕ without milk and sugar while fasting.
What is allowed during intermittent fasting?
During intermittent fasting, you are allowed to drink water, mineral water, black coffee ☕, green, black, white, or oolong tea 🍵 without milk and sugar or sweeteners.
What can you eat or drink while intermittent fasting?
You can drink water, mineral water, black coffee ☕, green, black, white, or Oolong tea 🍵 without milk and sugar while intermittent fasting. In your feasting period, a ketogenic diet suits best since such as fasting, it aims at burning fat 🔥 for energy.
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