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ISSA, International Sports Sciences Association, Certified Personal Trainer, ISSAonline, Should I Drink Protein Shakes on Rest Days?

Should I Drink Protein Shakes on Rest Days?

Reading Time: 5 minutes 20 seconds


DATE: 2023-06-07

It’s important to train hard and recover well. A big part of recovery is nutrition. Protein, in particular, is a big player when it comes to seeing results in body composition, muscle growth, and weight loss. And protein shakes have become a convenient option for increasing daily protein consumption. But should you drink protein shakes on rest days?

In this article, we will review the importance of protein not only on workout days but also on rest days. We’ll also cover the benefits of including a protein shake on rest days and options to maximize protein consumption for muscle growth and muscle recovery.

What is Protein and Why is it So Important?

Protein is one of the three primary macronutrients. Protein is composed of building blocks called amino acids. Amino acids are organic compounds made of carbon, hydrogen, nitrogen, oxygen, and sulfur. Just like amino acids are the building blocks of protein, proteins are the building blocks of muscle.

The primary function of protein consumed in the diet is building and repairing cells such as muscle cells damaged while exercising. During resistance training at the gym, muscle fibers sustain damage. This damage is a natural response necessary for muscle development and growth. Following muscle fiber damage, the body repairs the damaged fibers by fusing them. This fusion of muscle fibers results in increased muscle mass and size.

Therefore, consuming protein after a workout is essential to repair and build muscle. Eating protein after exercise provides your body with the necessary amino acids to repair and rebuild muscles that experience damage.

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How Much Protein Does the Body Need to Support Muscle Growth and Repair?

One common question among active consumers is how much protein our bodies need. According to The American College of Sports Medicine (ACSM), individuals lifting weights regularly should consume 1.2-1.7 grams of protein per kilogram of body weight per day. This is equivalent to 0.5 to 0.8 grams of protein per pound of body weight.

Example: A 150 lb individual should consume anywhere from 75 grams (0.5 x 150) to 120 grams (0.8 x 150) of quality protein per day.

Daily protein intake needs can vary from person to person. Encourage your clients to work closely with a personal trainer or nutritionist to determine what macronutrient breakdown works best to support their goals.

Do You Need To Take Rest Days?

While it may seem counterintuitive, rest days are just as important for building muscle. Working out is step one. Following muscle breakdown in the gym, rest is necessary to repair and rebuild muscle cells. Some recovery happens between gym sessions. However, an occasional longer rest day may be necessary to avoid overtraining.

Rest days are all about recovery. Think of it as a day where you give your body what it needs to recoup and be ready to get back to work fully. Rest days exist to help you recover and grow. Progress takes place during the recovery process, not in the gym itself. Work closely with your clients to create a workout schedule and plan that works best for them to support adequate recovery.

Do You Need Protein on Rest Days? Is Protein Powder a Good Source of Protein for Rest Days?

One common question is whether or not you should eat differently when you’re in recovery mode versus the days you hit the gym. The simple answer - not really. Nutrition on rest days should look pretty similar to workout days. This is because your body needs the same nutrients even on the days you’re not working out to recover properly.

Protein is essential for supporting muscle recovery on rest days. It’s important to consume high-quality protein sources on non-workout days to optimize recovery. One high-quality protein source to include on both active and rest days is protein shakes.

Unlike other fitness supplements that require proper timing, protein shakes can be an excellent option for rest days. You can consume protein powder at any point of the day most of the time. The most important thing about protein is consuming the desired amount for the day rather than timing.

Protein shakes can be a great option for athletes, bodybuilders, or ordinary gym-goers who want to lose fat or build muscle. Protein shakes are a great option on non-workout days. According to a study in 2017, whey protein may enhance protein metabolism and speed up recovery. Protein shakes may also reduce muscle sorenessfrom physical activity.

Protein shakes are a convenient way to consume adequate protein on rest days. Anyone who exercises regularly likely requires a higher daily protein intake than sedentary individuals. A study in 2000 showed that active individuals need up to two times as much protein as non-active individuals.

Choosing a Protein Powder

There are many factors to consider when choosing a protein powder. One factor is protein type. There are many different types of protein powder. Some of the most commonly used protein powders include:

  • Whey protein powder

  • Soy protein

  • Egg protein

  • Brown rice protein

  • Pea protein

  • Hemp protein

  • Casein protein

It is also important to find a protein powder that matches your individual needs. Below are some guidelines for choosing a protein powder based on your goals.

  • Building muscle - It’s essential to choose a protein powder with a high biological value to support muscle growth if building muscle is the goal. The biological value is how well the body can absorb and utilize a protein. Whey protein and whey protein isolates are complete proteins and are the best options for muscle growth.

  • Losing weight - If weight loss is the primary goal, choosing a protein shake with no added sugars, dextrins, or maltodextrins is important. Individuals chasing weight loss may want to avoid protein powders with added branched-chain amino acids (BCAAs) as these help promote muscle growth and may result in weight gain.

  • Vegetarian or vegan - For individuals choosing to adhere to a vegetarian or vegan diet, it is best to avoid milk-based protein shakes. Instead, choose 100% plant-based proteins like soy, pea, and hemp.

While protein shakes can assist recovery and enhance overall results, it is truly up to individual preference whether or not they are a part of rest day nutrition. The most important thing is to consume adequate protein to meet your nutritional goals.

In Conclusion

Whether the goal is to build muscle, lose weight or improve overall fitness, recovery days are where the real magic happens. Protein shakes can be a healthy part of rest day nutrition and a great source of extra protein. However, protein shakes are not magic muscle fluid. Protein is a nutrient and can be consumed in a variety of forms. Encourage your clients to focus on getting adequate protein from quality sources on rest days and include a healthy protein shake if that’s something that fits their nutrition goals. It’s never the wrong time to make your diet more nutrient-rich, so don’t be afraid to include a protein shake on rest days. Give your body the tools it needs to maximize the work taking place on rest days.

Are you looking for a fruitful career in fitness? When you become an ISSANutritionist, you can help improve the quality of your clients' lives beyond the gym walls. Unlock your career in health and fitness as an ISSANutritionist.


Protein Intake For Optimal Muscle Maintenance. Acsm.Org. https://www.acsm.org/docs/default-source/files-for-resource-library/protein-intake-for-optimal-muscle-maintenance.pdf.

West, D., Abou Sawan, S., Mazzulla, M., Williamson, E., & Moore, D. R. (2017). Whey Protein Supplementation Enhances Whole Body Protein Metabolism and Performance Recovery after Resistance Exercise: A Double-Blind Crossover Study. Nutrients, 9(7), 735. https://doi.org/10.3390/nu9070735

Kårlund, A., Gómez-Gallego, C., Turpeinen, A. M., Palo-Oja, O. M., El-Nezami, H., & Kolehmainen, M. (2019). Protein Supplements and Their Relation with Nutrition, Microbiota Composition and Health: Is More Protein Always Better for Sportspeople?. Nutrients, 11(4), 829. https://doi.org/10.3390/nu11040829

Lemon PW. Beyond the zone: protein needs of active individuals. J Am Coll Nutr. 2000 Oct;19(5 Suppl):513S-521S. doi: 10.1080/07315724.2000.10718974. PMID: 11023001.

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