Do Protein Shakes Make You Gain Weight Without Working Out?

📌 Overview and Key Takeaways

Do protein shakes make you gain weight without working out?

Discover how protein supplements can support weight gain.

Last Updated
Jan 21, 2026

Author and Medical Reviewer

Written by Jack, Founder

Jack is the Founder of Drink Wholesome.

Medically reviewed by Brittany, MS, RD and Jenn, PA-C

Kayla is a Registered Dietitian with a MS in Nutrition.

Jennifer is a Physician Assistant with a BA in Nutritional Sciences.

Protein Shakes and Weight Gain

Will Drinking Protein Shakes Make Me Gain Weight?

Although protein shakes are often championed as a weight loss food, they can also help you gain weight.

This may seem paradoxical, but it makes perfect sense because depending on how they are used, protein supplements can help you achieve a calorie deficit or surplus.

And losing weight is all about achieving and maintaining a calorie deficit – eating fewer calories than you burn.

Gaining weight, on the other hand, comes down to achieving and maintaining a calorie surplus – eating more calories than you burn.

You have to burn 3,500 more calories than you eat to lose a pound, or eat 3,500 more calories than you burn to gain a pound.

And to lose or gain weight at a safe rate – 0.5 pound per week – you need to achieve a weekly calorie deficit/surplus of 1,750 calories.

Increasing the percentage of your calories by replacing a meal or part of a meal with a protein shake can help you create a calorie deficit because:

• Protein is the most satiating macronutrient, meaning it keeps you feeling full for longer than nutrients like fats and carbs, which curbs cravings and overeating (Am J Clin Nutr, 2008).
• Protein increases thermogenesis, or your metabolic rate and energy expenditure (J Am Coll Nutr, 2004).
• Eating protein, when paired with resistance exercise, can help you build muscle, and people with more muscle mass have faster metabolisms (burn more calories) (Nutrients, 2019).

On the contrary, simply adding a protein shake to your diet, if nothing else about your diet or lifestyle changes, can help you create a calorie surplus.

So, protein shakes can make you gain weight without working out, as long as they allow you to eat more calories than you burn.

Note that working out – doing resistance training (i.e. lifting weights) – is essential if you want to build muscle.

Your muscles need amino acids to grow and repair themselves, and some of these amino acids (the building blocks of protein) must come from food or supplements.

How Much Protein Do I Need?

The current recommended dietary allowance (RDA) for protein is 0.36 grams per pound of body weight per day for sedentary adults (Food Funct, 2016).

This amounts to 50-60 grams per day for men and about 40-50 grams for women.

Keep in mind that this is the bare minimum required to meet basic nutritional needs.

The actual amount of protein you need can vary depending on a number of factors, however, including age and activity level.

People who regularly lift weights, for instance, may need to consume 150+ grams of protein per day to build and maintain muscle mass (J Int Soc Sports Nutr, 2017).

What Are the Best Protein Shakes for Weight Management?

As long as you are eating a balanced diet, the type (egg, pea, whey, etc.) of protein you consume does not matter.

Ingredients do matter, however.

Many protein supplements contain ingredients known to cause painful side effects and even long-term health problems.

🚫 Avoid Food Additives

Regularly eating food additives can alter the composition of your gut microbiome (North Clin Istanb, 2019).

This can lead to gut dysbiosis, or an imbalance in gut bacteria, which can impair weight management efforts through several mechanisms (Microorganisms, 2022).

For instance, gut dysbiosis can diminish your ability to digest and absorb the food you eat, which, as you might imagine, can make it hard for you to gain weight (Microbiome, 2019).

It can also affect the release of hunger-controlling hormones such as ghrelin and insulin, which could have the opposite effect (N Engl J Med, 2024).

⚠️ Here is a list of the most common food additives in meal replacements:

• acacia fiber
• acacia gum
• acesulfame potassium
• artificial flavors
• ascorbic acid
• aspartame
• calcium carbonate
• carrageenan
• cellulose gum
• dextrin
• dicalcium phosphate
• dipotassium phosphate
• erythritol
• gellan gum
• guar gum
• gum arabic
• inulin
• locust bean gum
• maltitol
• maltodextrin
• mono- and diglycerides
• ‘natural’ flavors
• rice bran extract
• rice dextrin
• rice hulls
• rosemary extract
• silica
• silicon dioxide
• sodium alginate
• soluble corn fiber
• sorbitol
• soy lecithin
• sucralose
• sunflower lecithin
• tocopherols
• tricalcium phosphate
• xanthan gum
• xylitol
• zinc oxide

Note that this list includes several artificial sweeteners.

Artificial sweeteners like sucralose and acesulfame potassium are among the worst ingredients for your gut microbiome (Nature, 2014).

They both reduce microbial diversity and promote the growth of potentially pathogenic bacteria.

Also note that as a rule of thumb, if you cannot find it in nature or make it at home, it is probably a food additive.

🚫 Avoid Dairy-Based Proteins

Dairy-based proteins like whey and casein, although not an issue for everyone, can cause digestive issues.

This is usually because they contain lactose, a sugar many individuals with sensitive stomachs cannot fully digest.

But you might be sensitive to dairy-based proteins even if you are not lactose intolerant.

This is particularly true for casein protein, which forms a gel-like substance in your stomach that slows down digestion.

🚫 Avoid Protein Concentrates and Isolates

You might also want to avoid ultra-processed protein concentrates and isolates.

Most protein supplements are made from one or both of these ultra-processed protein sources, which have been mechanically and/or chemically stripped of everything but the protein.

This includes the enzymes, fiber, and other natural digestive aids that help your gut break them down.

You therefore do not digest them in the same way that you do whole foods, which could affect your gut health.

Studies show that regularly eating protein concentrates and isolates might disrupt your gut microbiome (Nutrients, 2018) and cause the formation of toxic byproducts in your gut (Mol Nutr Food Res, 2024).

You should thus look for protein supplements made from whole food protein sources like egg whites and almonds, which are easier to digest and absorb.

Order Samples to see for yourself.

Sources

1. The American Journal of Clinical Nutrition (Am J Clin Nutr). Protein, weight management, and satiety. 2008.
2. Journal of the American College of Nutrition (J Am Coll Nutr). The effects of high protein diets on thermogenesis, satiety and weight loss: a critical review. 2004.
3. Nutrients (Nutrients). Dietary Protein and Muscle Mass: Translating Science to Application and Health Benefit. 2019.
4. Food & Function (Food Funct). Dietary protein intake and human health. 2016.
5. Journal of the International Society of Sports Nutrition (J Int Soc Sports Nutr). International Society of Sports Nutrition Position Stand: protein and exercise. 2017.
6. Journal of the International Society of Sports Nutrition (J Int Soc Sports Nutr). International Society of Sports Nutrition Position Stand: protein and exercise. 2017.
7. Northern Clinics of Istanbul (North Clin Istanb). Food additives and microbiota. 2019.
8. Microorganisms (Microorganisms). Gut Microbiota Dysbiosis: Triggers, Consequences, Diagnostic and Therapeutic Options. 2022.
9. Microbiome (Microbiome). The neuroactive potential of the human gut microbiota in quality of life and depression. 2019.
10. The New England Journal of Medicine (N Engl J Med). The Microbiome and Human Health. 2024.
11. Nature (Nature). Artificial sweeteners induce glucose intolerance by altering the gut microbiota. 2014.
12. Nutrients (Nutrients). Effect of a Protein Supplement on the Gut Microbiota of Endurance Athletes: A Randomized, Controlled, Double-Blind Pilot Study. 2018.
13. Molecular Nutrition & Food Research (Mol Nutr Food Res). In Vitro Fermentation of Animal and Plant Protein Isolates by the Human Gut Microbiota Under High and Low Carbohydrate Conditions. 2024.

Editorial Guidelines

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This article was written by a Registered Dietitian and reviewed by a Physician Assistant. We rely on peer-reviewed research and trusted medical sources, and regularly update our content to ensure accuracy and clarity.