Affiliate links on our site may earn us commissions. Learn More.

This website uses cookies. By continuing to use this website you are giving consent to cookies being used. Visit our Privacy Policy.


Discover The Best Wellness Tips In Your Inbox

Subscribe to Health Reporter’s newsletter and get our health experts’ highlights and the latest news about healthy living.
The newsletters are spam-free and sent from our health experts and professionals.

Thank You!

You have successfully subscribed to our newsletter!
Home arrow Nutrition arrow Intermittent Fasting arrow Does a Protein Shake Break a Fast? Hint: It Contains Calories

Does a Protein Shake Break a Fast? Hint: It Contains Calories

Wendy Lord, RD
Written by Wendy Lord, RD
Fact checked by Edibel Quintero, RD
Last update: October 22, 2023
4 min read 1406 Views 0 Comments
clock 4 eye 1406 comments 0

A protein shake is a convenient way to boost protein intake, but does it break a fast? Keep reading to find out more about protein and fasting.

does a protein shake break a fast

Protein shakes have become a popular way to boost the amount of protein in your diet. All you have to do is place a scoop of protein powder and the recommended amount of water in a shaker, twist on the lid, shake, and drink.

However, if you regularly consume protein shakes, it‘s easy to forget that your favorite protein powder is a meal in a glass. And protein is a macronutrient that provides the body with energy. Your liquid meal may also contain carbohydrates and fat, increasing the calorie content.

This article gives you all the information you need to include protein shakes while intermittent fasting without jeopardizing your efforts. 

Does a Protein Shake Break a Fast?

Protein shakes break a fast. Protein is a macronutrient that provides the body with 4 calories per gram. So, if it’s the first thing you consume after your overnight fast or workout session, it will break it.

Intermittent fasting has become a popular way to limit your calories and make weight loss easier. With more than 10 different fasting regimens to choose from, you are sure to find one that works for you. Consuming protein shakes while you are on intermittent fasting is fine, but you must take your eating window into consideration.

Remember, you can drink while fasting, but protein shakes are caloric beverages. Therefore, when you drink one, you will break your fast.  So, if you drink whey protein before heading off to the gym at 6 AM every morning, and your last meal at night is at 8 PM, your overnight fast is only 10 hours. As a result, it’s going to be challenging to maintain your calorie restriction. So, save it for your eating window.

Do You Need Protein While Intermittent Fasting?

Yes, protein is important to achieve the best results while intermittent fasting. Actually, we all need to incorporate an adequate amount of protein in our diet as it is the building block of muscles.

Protein consists of chains of amino acids, the building blocks of all proteins. When you eat meat, fish, poultry, dairy products, legumes, and nuts, the protein in them is broken down during digestion into these basic units. 

And then, your body uses them to build muscle and other body components, including enzymes, antibodies, hormones, and transport structures. For example, oxygen is carried from your lungs to your muscles attached to hemoglobin, a protein-based transport unit. 

So, if you don’t consume enough protein in your diet, your muscles will become weak, and your body isn’t going to function as well as it should. Consequently, protein is essential even when you do intermittent fasting.

How Much Protein Do You Need per Day? 

Protein recommendations vary from 10–35% of your daily calorie intake, depending on your health status and activity level. So, if you eat 2,000 calories daily, your protein would account for 200–700 calories or 50–175g. 

The recommended protein intake is 0.36g of protein per pound of body weight. So, if you weigh 180lbs, you would need to eat 65g of protein to prevent a deficiency. 

Considering that 30g of red meat and 40g of fish or chicken provide 7g of protein, achieving 64g daily is relatively simple. But, if you are vegan, it can be a little more challenging because the protein concentration in plant-based foods isn’t as concentrated.

When you drink protein shakes, meeting and exceeding your protein requirements is easy. The average protein powder provides about 21g of protein per serving.

Can Protein Shakes Cause Weight Gain?

Protein shakes can cause weight gain because they are a source of energy. If you drink a shake without adjusting your food intake, you could consume more calories than you should to lose weight.  

Losing weight requires you to create an energy deficit. So, the number of calories you eat must be less than the number of calories you burn daily. And intermittent fasting can make it easier to achieve a negative energy difference.

If you are trying to lose weight, a protein shake would most likely serve you best as a meal replacement. It can help you control your energy intake and ensure you still meet your protein requirements.

But, if you use a protein powder as a supplement after a workout or as a snack between meals, you could exceed your daily calorie allowance. And the result of that is weight gain.

Can You Use a Protein Shake to Break a Fast?

You most definitely can break your fast with a protein shake. Protein provides essential amino acids to help repair the body and cells.

The definition of a fast is a period without food. It could be a full 24 hours, 16 hours overnight, or 4 hours between meals. A fast is broken as soon as you eat something that contains calories that stimulate your metabolic processes. 

As a meal replacement, your protein shake can be included when you are intermittent fasting. But, you should always drink it within your eating window. Remember, it is a meal and not a beverage. So it will break your fast.

A Word From a Dietitian

Intermittent fasting is a helpful tool for weight loss and resetting your metabolism for improved blood sugar control and overall health. The benefits come from creating a calorie deficit and the extended overnight fasting period.

Therefore, a 16-hour fast is recommended for maximum effect. You are therefore required to delay the first meal of the day to create this calorie-restricted window. So, if you drink a protein shake during fasting, your fasting will be broken.

Remember, a protein powder is a supplement to boost your protein intake. And it contains calories that stimulate digestion and metabolism, which signals the end of your fasting period. Before you mix up your next shake, consider if you need more protein in your diet.


Protein shakes are extremely popular. But, people often forget that protein is a macronutrient that provides the body with 4 calories per gram. So the average protein shake that contains 21g of protein also has at least 84 calories.

It might not seem like much, but calories are responsible for breaking a fast. So, next time you mix a protein shake to drink in the morning, remember that you will be opening your feeding window and bringing an end to your overnight fast.

Written by Wendy Lord, RD
Wendy is a Registered Dietitian with a passion for writing about nutrition, health, and medicine. Her aim is to translate the medical jargon to make information accessible to everyone so that they can make informed decisions about their health.
The article was fact checked by Edibel Quintero, RD
Was this article helpful?
Thank you! We received Your feedback
Wendy Lord, RD
Written by Wendy Lord, RD
Fact checked by Edibel Quintero, RD
Last update: October 22, 2023
4 min read 1406 Views 0 Comments

Leave a comment

Thank you for your comment!
We will review it as soon as possible.
Your Name
Missing required field
Your Comment
Missing required field