Does Coffee Break a Fast? (Put This in Coffee While Fasting)

Imagine waking up and reaching for the comforting cup of morning coffee, but then… wait! Can you drink coffee while fasting? Or will it break a fast?

The good news is that most can drink coffee while fasting, but there is still a gray area that you should know about. The answers aren’t totally clear, and many worry that the morning coffee could break your fast and ruin your results.

It’s easy to be confused with so much mixed advice out there on drinking coffee and intermittent fasting. Should you give up drinking coffee during intermittent fasting if you want to maximize your results? Or you may be in the clear and can even get better results by drinking coffee while fasting.

You don’t have to keep guessing! Here I’ll break down everything you need to know about coffee’s effects on fasting, if it breaks a fast or not, the best coffee to drink while fasting, and what to put in your coffee while fasting for the best and fastest results.

What Happens if You Drink Coffee While Fasting

But if you’re following a strict water fasting plan, drinking anything other than water is a no-no. There is a belief that having anything other than water could metabolically cause a slight change in your body that may take away some of the intermittent fasting benefits.

Yet, intermittent fasting for weight loss gives more leeway for coffee consumption. Black coffee is probably the least controversial drink while fasting. However, many don’t like the taste of black coffee and prefer to have creamer, milk, or other sweetener added.

What you put in coffee while fasting can definitely change the acceptability. Adding sugar will break your fast because it spikes your blood sugar and insulin levels. But there are other creamers and sweeteners you can add to coffee that won’t break your fast.

Intermittent fasting is like an all-or-nothing on/off light switch. You can have 5, 10, 15, or even up to 50 calories from certain foods without completely breaking your fast. The fasting results dial may get turned down shortly after, but if it helps to keep you fasting for longer, then you’ll get better results in the long run.

3 Benefits of Drinking Coffee While Fasting

Drinking coffee while fasting will not only keep you in a fasted state, but it also brings a lot of benefits. So if you’re used to drinking coffee, then most should keep doing so and reap the benefits.

Increased Metabolism: Coffee’s caffeine content can boost your metabolism. Caffeine increases thermogenesis (the process when your body generates more heat and energy by burning calories) even at rest, allowing you to burn more body fat.¹

Caffeine promotes fat oxidation, helping your body break down fat stores and use them as fuel.² This fat-burning effect is amplified while fasting since your body is already starting to burn fat for fuel.

Coffee’s caffeine can increase your resting metabolic rate (RMR) by up to 11%.³ Caffeine stimulates your central nervous system (CNS), causing a heart rate increase. This allows your body to burn even more calories while resting since more energy is needed due to a higher RMR.

Curbs Hunger: Coffee blunts hunger (allowing you to continue fasting deeper into the day), which leads to more fat loss and weight loss.⁴

Anyone who has tried intermittent fasting before knows the hardest part is the occasional hunger. Curbing hunger without breaking your fast is a key part of sticking with intermittent fasting.

Coffee lowers the “hunger hormone” ghrelin in your body, giving you a reduced appetite. Peptide YY is a hormone released by the gut after eating that tells your brain you’re full. Coffee also increases Peptide YY helping you to feel fuller for longer.⁵

Since caffeine gives your body a boost in energy, it can help distract you from feeling hungry. Stable blood sugar levels can also help prevent the hunger pangs that come with going long periods without eating.

Enhances Ketogenesis: One of the main reasons why intermittent fasting is so effective for fat loss and weight loss is because it activates ketogenesis.⁶ Ketogenesis is the process when your body starts making ketones from fat stores.

During intermittent fasting, there are no more quick-burning sugars coming in available for your body’s energy needs. So it has to start breaking down stored fat to use as fuel.

Caffeine promotes lipolysis (breakdown of body fat), which releases more body fat into fatty acids that are then converted into ketones.⁷ Caffeine increases plasma ketones with 1-3 cups of coffee, making the same as an overnight fast.⁸

This process enhances ketogenesis and shifts your body into an elevated fat-burning state. Taking C8-MCTs (caprylic acid) with your coffee while fasting can also elevate this ketogenic fat-burning to a higher level. C8-MCTs are also converted into ketones via your liver, triggering even more ketogenic fat-burning.⁹

Drinking Coffee on an Empty Stomach

For some, drinking coffee on an empty stomach could slightly raise cortisol (the stress hormone) levels.¹⁰ This is due to the caffeine in coffee, which stimulates the adrenal glands to release cortisol. Cortisol levels naturally peak in the morning, and drinking coffee could add to this spike.

But this increase in insulin levels is probably small and short-lived (if any) for most. If you’re very sensitive to caffeine, then you could have a higher cortisol spike than others. Cortisol could mobilize blood glucose and interfere with ketosis.¹¹

Drinking coffee on an empty stomach when you’re already stressed out may lead to a higher cortisol response. If you’re sensitive to caffeine, stressed out, and have a low caffeine tolerance, then you could instead drink decaffeinated coffee.

Even black coffee can cause blood sugar spikes in type 1 diabetics, but it doesn’t spike as high as a donut. Studies have found that type 2 diabetics who practice intermittent fasting and drink black coffee can have improved insulin sensitivity, blood glucose regulation, and weight loss.¹²

If you’re following a 16/8 fasting window then it’ll be a lot easier for most to keep drinking coffee. I try to wait 90 minutes after waking before drinking coffee. This is to allow adenosine (the sleepy chemical in the brain) to clear out so you won’t have a caffeine crash after drinking coffee.¹³

Many people in the intermittent fasting community still drink coffee and see great results with weight loss. But measuring with a blood sugar monitor is the only way to know 100% for sure if coffee causes your blood sugar to spike.

Does Coffee Stop Autophagy?

Autophagy is your body’s natural way of cleaning out old damaged cells and making room for new healthy ones. Intermittent fasting can kickstart autophagy by giving your body a break from digesting food and then triggering the recycling of cells.¹⁴

But can you drink coffee while fasting and still activate autophagy?

The good news is you can still activate autophagy during intermittent fasting while drinking coffee. Studies have found the antioxidants in coffee can promote autophagy and even put your body into a deeper state of autophagy.¹⁵

The polyphenols in coffee that have antioxidant properties are chlorogenic acid and caffeic acid. These powerful polyphenols support cellular health, reduce inflammation, and trigger autophagy without breaking a fast.¹⁶

Drinking coffee can activate protein deacylation. This is when compounds in coffee help remove small chemical groups (acyl groups) from proteins in your cells. This clean-up process improves how well proteins work, helping your cells function better, and enhancing autophagy.

Coffee can reduce mTOR, the cellular pathway that controls body growth and nutrient use. Low mTOR activity encourages the body to shift to repairing mode, and activate autophagy.¹⁷

Dr. Ruth Patterson has studied breast cancer survivors drinking black coffee, and found those who consumed coffee during their fasting window had a lower breast cancer occurrence rate.¹⁸

You’ll still get the autophagy benefits if you drink decaffeinated coffee. Since it’s the polyphenols that activate autophagy, it doesn’t matter if you drink coffee with or without caffeine.

Best Coffee for Intermittent Fasting

There are many different forms of coffee so it’s good to know which ones are the best for intermittent fasting. And you should know the coffee forms that could break a fast…

Ideally, it’s best to drink clean coffee that is organic and mold-free. Some coffee contains mold that produces mycotoxins. These are harmful compounds that can have negative health effects.

Organic coffee is healthier than regular coffee since it has less chemical exposure. Pesticide residues can get into coffee beans, but if organic is too pricey for you, the risk is usually lower than that of other types of food.

Studies have found that organic farming can lead to higher antioxidant levels in plants like coffee.¹⁹ Coffee is rich in antioxidants, so due to higher polyphenol levels, organic coffee will provide more benefits.

Organic coffee is typically sourced from higher-quality farms with better drying and processing practices. These practices lower the risk of mold and mycotoxins. But at the very least, drink high-quality and well-sourced coffee.

Caffeinated coffee is generally better than decaf coffee for health benefits while fasting. Caffeine boosts metabolism, increases energy levels, and curbs hunger. But if you prefer decaf coffee then continue drinking it while fasting and you’ll still get some of the benefits.

Some more forms of coffee that won’t break a fast:

• Chicory coffee
• Instant coffee
• Green coffee
• Cold Brew
• Nespresso pods
• Espresso

I’d stay away from flavored coffee pods unless they explicitly say they do not contain sugar. K-cup pods will leave microplastics in the coffee that will seep into your body.²⁰ Microplastics are tiny pieces of plastic that cause inflammation and oxidative stress and disrupt hormonal balance.²¹

Drinking Coffee With Creamer While Fasting

Make sure the coffee creamer you’re using doesn’t contain added sugars, as this could spike your insulin levels andbreak your fast. Many popular brands, like Coffee Mate, contain 5g of added sugar per serving, which isn’t ideal.

There’s a “50-calorie rule” that many people who fast for weight loss can follow. This rule allows a small amount of calories from the right foods without breaking the fast. You may temporarily reduce your fasting benefits for weight loss right after but should return to a fasted state not much longer.

So, if adding a little bit of creamer to your coffee makes you happy and keeps you fasting, then you’ll get better results in the long run from using it. Follow this list of the best coffee creamers for intermittent fasting to know what to have.

I personally use and recommend a keto coffee creamer called Keto Elevate. This creamer is in powder form and contains 100% C8-MCTs that your body converts into ketones, helping to kickstart ketogenic fat burning. They won’t break your fast and will accelerate your results.

It tastes just like a delicious creamer and mixes easily into coffee or tea, unlike messy MCT oils that contain a blend of multiple amounts of MCTs. C8 MCTs are the best form of MCTs since they’re so efficiently converted into ketones by your body, making them more ketogenic.²²

What to Put in Coffee Without It Breaking a Fast

Along with a coffee creamer, you can also put other ingredients into your coffee without it breaking your fast. But there are many popular coffee additives that will break your fast and should be avoided with your coffee intake.

Milk

You can add a small amount of milk to your coffee while fasting without it breaking the fast. Try to stick with a little bit of whole milk instead of skim or low-fat milk because the higher fat content will help to slow absorption and prevent the insulin response.²³

50 calories of whole milk is equal to about 1/3 cup. This is the upper limit of how much whole milk you should add to your coffee while fasting. But it’s always better to consume less than that.

However, some have had a harder time losing weight when adding milk to their coffee during their fasting window. So, if you’re not getting results, consider switching to black coffee instead.

A trick is to add a little bit of cinnamon to your morning coffee. Cinnamon improves insulin sensitivity and slows down carbohydrate breakdown to prevent the insulin spike.²⁴ Cinnamon also activates enzymes in your body to better absorb sugar into your blood, reducing blood sugar levels.

Half-and-Half

Half-and-half is a dairy blend of equal parts whole milk and heavy cream. This gives it a richer texture than milk, but it’s also lighter than cream.

You can add half-and-half to your coffee while fasting since it contains more fats than even whole milk.

2.5 tablespoons of half-and-half is equal to 50 calories, so this is the highest amount you should add to coffee without breaking your fast.

Heavy Whipping Cream (35% Fat)

There is very little sugar in heavy whipping cream since it’s mostly fat with a small amount of protein. It does contain a small amount of lactose (a natural sugar in milk), but this amount is very low and shouldn’t break your fast.

Heavy whipping cream creates a smaller insulin spike than whole milk and half and half. The high amount of fat slows digestion, allowing a more gradual absorption of the cream and resulting in a much smaller insulin response.

1 tablespoon of heavy whipping cream is equal to 50 calories, so this is the most you’ll want to add to coffee.

Butter and Ghee

Butter is made from churning cream, which separates the fat from the liquid. This makes butter just about all fat without any carbohydrates or sugars. Ghee is clarified butter removing all liquid and leaving behind pure butterfat.

You can add butter or ghee to your coffee intake since butter and ghee are higher in fats and very low in sugars. But keep in mind that butter and fat are higher in calories since they’re so dense in fats.

1/2 tablespoon of butter is equal to 50 calories. And just under half a tablespoon is equal to 50 calories.

Try to go with unsalted grass-fed butter since it’s higher in omega-3s and CLA.²⁵ Grass-fed cows also produce higher-quality milk with a better healthy fats profile, which gives the butter more vitamins and fewer inflammatory fats.²⁶

Bulletproof coffee is a high-fat coffee drink made by blending black coffee with butter or ghee and MCT oil. It’s made with 1 cup of coffee mixed with 1-2 tablespoons of butter and 1 tablespoon of MCT oil.

In my opinion, Bulletproof coffee is way too high in fats and calories to have during intermittent fasting. You’ll have over 300 calories from the butter and MCT oils with Bulletproof coffee. This for sure will break your fast, but could possibly still keep you in a ketogenic state.

Anybody who’s tried Bulletproof coffee will let you know how quickly it can upset your stomach. So if you’re going to try it, start off with a much smaller amount of butter and MCT oil .

Unsweetened Almond Milk

You can put unsweetened almond milk in your coffee without it breaking your fast. Unsweetened almond milk is lower in calories than milk but also doesn’t contain sugar (since it’s unsweetened).

One cup of unsweetened almond milk has less than 50 calories. If you’re on a low-carb or low-calorie diet, unsweetened almond milk can be a good choice.

However, I generally avoid almond milk because it contains additives and is higher in omega-6 fats. Almond milk is also high in oxalates, so if you are prone to kidney stones, then it’s best to avoid it. If you’re looking for a dairy alternative, I prefer organic coconut milk.

Oat Milk Creamer

I’ll start by saying I’m not a big fan of oat milk or oat milk creamer. Oat milk has more sugars than regular milk and other added ingredients like bad vegetable oils. It might sound like a healthier option, but in my opinion, it isn’t. 

But as far as if it’ll break your fast, it’s about the same as regular milk. It does contain added sugars, so it’s not a great choice to add to your coffee when fasting. So if you really want to have some oat milk, keep it at a small splash and use unsweetened oat milk.

Coconut Milk Creamer

Coconut milk is similar to almond milk meaning there aren’t a whole lot of nutrients in it. It’s mostly watered down to the point the nutrients left are low.

You also have to check the nutrition facts label on the coconut milk to make sure there aren’t any added sugars. Manufacturers like to add sugar to sweeten up the coconut milk creamer to improve its taste.

But adding a little coconut milk or coconut milk creamer to your coffee isn’t going to break your fast. Coconut milk itself is very low on the glycemic index so that’s even further evidence it shouldn’t cause an insulin spike.

Just make sure to keep it at 1 tbsp or less in your coffee and make sure the coconut milk creamer is unsweetened and doesn’t contain added sugars.

Coconut oil is a popular choice to put in coffee, but keep in mind it will break your fast since it’s so calorie dense.

Soy Milk Creamer

Like oat and almond milk, Soy milk is mostly a watered-down processed food. But soy milk does contain the closest nutritional profile to cow’s milk.

People who take soy milk end up with nutritional deficiencies, and even if it does help build muscle, it’s not as much as cow’s milk.²⁷

If you’re lactose intolerant, you’re better off using lactose-free cow’s milk. Soy farming is notorious for bad practices, such as using a higher amount of pesticides and fertilizers.

MCT Oil or Powder

MCTs (medium-chained triglycerides) can take your fast up to another level and give you better results. They contain some calories on paper, but they aren’t processed like other calories. Instead, they’re instantly shuttled over to your liver, where they’re converted into ketones.²⁸

Ketones are what your body makes from fat stores for energy when it’s no longer getting quick-burning sugars or carbs for fuel. This is what happens on the keto diet… you stop eating carbs, and your body has to switch to the next fuel source, your fat stores.

So by taking these MCTs, you can “flip the switch” and jumpstart the fat-burning process by signaling your body to create ketones for fuel.

C8-MCTS (caprylic acid) are your body’s preferred source of MCTs. They’re most efficient and quickest to be converted to ketones by your body. Most MCT oil contains a blend of multiple MCTs that your body has a harder time converting.

Zero Calorie Sweeteners

Zero-calorie sweeteners are generally considered safe to add to coffee without breaking a fast. Since they don’t contain any calories, they should be fine when added in small amounts.

This is why you could theoretically still consume zero-calorie beverages like Coke Zero and energy drinks during your fast. I don’t personally recommend them, but they’re better than sugary beverages during your fasting window.

However, there is a belief that artificial sweeteners could activate a cephalic response in the body. Sucralose is 600x sweeter than table sugar, so your body can raise insulin levels in anticipation of incoming calories.²⁹

But this is probably more based on the individual. Some are more prone to an insulin response from zero-calorie artificial sweeteners like sucralose (Splenda) and aspartame (Equal) than others. If you have healthy insulin sensitivity and regularly consume artificial sweeteners during your fast, then your body should become used to it.

I usually recommend sticking with natural zero-calorie sweeteners instead:

• Stevia
• Monk Fruit
• Allulose

These natural-based sweeteners contain zero calories and can be added to coffee during fasting. If you prefer a sweeter coffee beverage, you can mix in a little bit of whole milk with stevia.

Honey

Putting honey in your morning coffee will definitely break your fast since it’s very high in sugar.

Honey is 40% fructose and 30% glucose, both of which are sugars. Fructose is broken down in your liver, but the glucose will spike your blood sugar and insulin breaking your fast.

It’s best to avoid honey in your coffee when fasting. But if you are going to use honey make sure it’s raw honey. Raw honey is rich in antioxidants, natural enzymes are preserved, and has immune boosting properties.

Summary

• You can drink coffee while fasting if your main goal is weight loss. Black coffee is the least debated form of coffee consumption that won’t break you fast. But there are other ingredients you can add to coffee to make it taste better while boosting your results.
• Drinking coffee during fasting can boost your metabolism giving you better results. Coffee during fasting can also curb hunger, increase energy, improve focus and increase ketogenesis.
• You can add some coffee creamer and milk to your coffee as long as it doesn’t break the “50 calorie rule.” Be careful with adding sugars since it will break your fast. But artificial sweeteners and natural sweeteners can keep you in a fasted state.