Can You Drink Coffee During Intermittent Fasting? - Perfect Keto

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Can You Drink Coffee During Intermittent Fasting?


Can you drink coffee during intermittent fasting?


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Intermittent fasting involves eating all your calories in a shortened eating window — say, between the hours of noon and 6 PM — and eating nothing for the rest of the day. 

There are many health benefits of fasting, ranging from weight loss and lower blood pressure to increased insulin sensitivity. 

But do you get those benefits if you drink coffee during your fasting period?

Or will a cup of coffee break your fast and leave you without the many benefits of intermittent fasting?

Here’s a look at the benefits of fasting, how coffee affects your fast, and why you may want to combine coffee with fasting. 

No, Black Coffee Won’t Break Your Fast

The key with fasting is calorie count. As long as food or drink doesn’t have calories, it won’t break your fast. 

That means black coffee is fine to pair with intermittent fasting. Technically it has about 4 calories per cup, due to natural oils and amino acids in the coffee beans — but 4 calories is not enough to impact your fasted state. 

That said, many coffee additions will break your fast. Milk, cream, collagen protein, sugar, creamer — anything with calories will take your body out of fasting mode. 

But as long as you drink it black , a morning cup of joe won’t interfere with your fasting window. In fact, it may enhance some of the benefits of fasting.

Will Zero-Calorie Sweeteners Break Your Fast?

If you prefer your coffee sweet, here’s some good news: zero-calorie sweeteners won’t break your fast, either. 

Sugar will break your fast, so it’s off the table. Your best bet is to choose natural calorie-free sweeteners. Good options are:

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  • Stevia
  • Monk fruit
  • Erythritol

It’s worth noting that while erythritol is fine — you digest virtually none of it — xylitol and other sugar alcohols may break your fast. 

Xylitol has calories and triggers a small but significant increase in blood glucose, which means it’s activating your digestion and potentially taking your body out of fasting mode[*]. 

Artificial sweeteners like sucralose and aspartame will not break your fast. 

But for the sake of your health, you’re probably better off avoiding artificial sweeteners and sticking to the natural stuff.

Can Coffee Enhance Weight Loss, Autophagy, and Other Benefits of Intermittent Fasting?

There are quite a few benefits of fasting. And as it turns out, drinking coffee during your fast may actually enhance those benefits, helping you see quicker improvements in your health. 


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Coffee Enhances Ketosis

Fasting is a quick and easy way to get into ketosis. When you don’t eat any food, your body will work through its carb stores, then begin to burn fat for fuel. As such, fasting pairs well with a keto diet, helping your body get into ketosis quickly.

Fasting alone is great for keto, but drinking coffee during a fast can add an even bigger boost to your keto diet. 

Recent research has found that caffeine increases ketone production[*], making coffee a great choice to pair with your fast. 

Coffee and Weight Loss

Daily coffee drinkers are more successful at keeping weight off long-term[*], possibly because coffee decreases appetite[*]. 

Coffee consumption also speeds up your metabolism, making it especially useful for fat loss[*]. 

Pairing coffee with intermittent fasting may help you fast longer without hunger and see quicker weight loss results. 

Coffee and Autophagy

Autophagy (Greek for “self-devouring”) is like spring cleaning for your cells. When autophagy turns on, your cells begin clearing out their old or damaged parts, replacing them with shiny new versions that work better. 

After autophagy, your cells are younger and more efficient. They’re also more resilient to stress, which makes autophagy a powerful tool to slow down aging[*]. 

Fasting is one of the best ways to activate autophagy[*]. And it turns out coffee turns on autophagy as well, adding an extra boost to your fast[*]. 

Coffee Additions: How to Drink Coffee Without Breaking Your Fast

If you aren’t a fan of black coffee, you likely want to add things to your morning cup of joe, even when you’re fasting. 

Be careful with what you add, though. A lot of common coffee additions will break your fast. 

Coffee Additions that Break Your Fast

  •  Keto coffee/Bulletproof Coffee. Keto coffee is delicious.It’s coffee blended with grass-fed butter and either coconut oil or MCT oil, and it makes for a great breakfast on a keto diet. But if you’re fasting, choose something else. With nearly 300 calories per cup, keto coffee will definitely break your fast.
  • Milk or cream. Both contain calories, which means lattes, cappuccinos, and other classic dairy-containing drinks are out during your fasting period. 
  • Any sugar-based sweetener. Honey, white sugar, brown sugar, agave syrup — all of it will stop your fast. 
  • Collagen or whey protein. While they’re great for you, collagen and whey will both break your fast. 

Fasting-Friendly Coffee Additions

Fortunately, you have quite a few fasting-friendly coffee options.

  • Zero-calorie sweeteners. Stevia, monk fruit, and erythritol are all great choices. 
  • Cinnamon. Cinnamon is good for controlling your blood sugar and insulin levels. And with no calories, it’s fine to add to your morning coffee during a fast.
  • Nutmeg. Another zero-calorie spice, nutmeg makes a delicious addition to coffee. Try grating some fresh over a cup of black coffee.
  • Almond milk (in small amounts). Unsweetened almond milk only has about 60 calories per cup. Adding a splash to your morning coffee is unlikely to break your fast. Just don’t add much, and avoid drinking several cups of coffee with almond milk throughout your fasting period. 
  • Espresso. Technically it’s not an additive, but espresso is fine to drink during your fast. It contains almost no calories and is a concentrated source of both caffeine and antioxidants. 

The Bottom Line: You Can Drink Coffee While Fasting

Should you drink coffee while fasting?

Ultimately, that’s up to you. If a cup of coffee makes you feel good during your fast, go for it. As long as you’re careful with what you add, coffee will not break your fast. In fact, it may even enhance it.

You can also opt for green tea or herbal tea during your fast, as neither will impact your metabolism. 

And if you haven’t tried intermittent fasting yet, it may be worthwhile to give it a shot. This beginner’s guide to intermittent fasting has everything you need to get started today.


Join 90k+ people who are losing weight with Keto Kickstart, our doctor-developed program designed to give you real weight loss results.


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