How Do Protein Shakes Help Weight Loss?

Protein shakes are used for many different reasons, by everyone from elite athletes to the average, occasional exerciser. Because they’re often used by bodybuilders to build muscle, you might think that drinking protein shakes will make you bulk up or gain weight — but the opposite can be true if they’re used correctly. Here, you’ll discover the ways in which protein works to help with weight loss, as well as ideas for how to incorporate them into your diet.

What are protein shakes?

Protein shakes are typically made from protein powder and water. However, you can combine protein powder with endless combinations of liquids and other ingredients to customize your own shake.

Protein powder is a convenient, shelf-stable protein source that can be used to help meet your workout goals, or simply to ensure that you consume enough protein each day. Alternatively, you can purchase high-protein, pre-packaged shakes in grocery, supplement, or health food stores. While you might think of protein shakes as being just for after a weight training session, they can be used throughout the day, in a variety of ways, to supplement your diet.

Weight loss

Research has shown that high protein diets can be an effective approach to weight loss.1 However, too much protein from animal sources can contribute to extra saturated fat and cholesterol, which is not heart-healthy. Protein powders provide a low-fat, low-cholesterol alternative to eating additional, larger portions of animal-based protein products.

When trying to lose weight, the bottom line is that you need to consume fewer calories than your body burns throughout the day. Everyone’s calorie needs vary depending on body size, body composition, health conditions, and activity levels. Protein shakes can help with weight loss in several different ways, as they can be used:

  • as a dieting tool
  • as a meal replacement
  • to help change body composition


Ghrelin and hunger

When it comes to feeling hungry, your hormones are what signal the brain to think that you need to eat. Ghrelin is the hormone in your body that controls your appetite — it’s often called “the hunger hormone”. Higher levels of ghrelin make us feel hungry, while lower levels keep us feeling satisfied.2

When you consume an adequate amount of protein (like 20 grams in a protein shake), the body responds by lowering the level of ghrelin in the body.2 When ghrelin levels are low, the brain stops telling us to feel hungry and seek out food. Research has shown that, the greater the protein in the diet, the lower the levels of ghrelin.3 The lower the level of ghrelin, the less likely you will be to overeat or to crave extra food throughout the day.

Diet tools

Protein, carbs, and fat are all digested slightly differently. Protein is one of the nutrients that actually slows down the digestive process, keeping food in the stomach for longer, which signals the brain to make you feel full and satisfied.2

This slow digestion rate also means that protein doesn’t cause major changes in blood sugar levels like high-carbohydrate foods do. A protein shake that’s low in sugar and fat can also be a great low-calorie snack alternative that will keep you feeling more satisfied than a high-carb snack, like a handful of pretzels or a cookie. Additionally, there’s no evidence of any potential side effects of protein supplements in healthy individuals.4


Meal replacements

Protein shakes are often used to prevent overeating. Sometimes, people choose to make a protein shake instead of consuming a meal. For example, consuming a shake for breakfast instead of eggs and toast.

In this case, you want to make sure that your shake contains the other essential nutrients for health – carbohydrates, fat, vitamins and minerals – so that it has a nutritive value similar to a full meal.

Protein shakes as meal replacements are a good option for several situations: when someone has trouble controlling portion sizes and easily overeats, when someone might not have time to cook/prepare a balanced meal and would skip a meal instead, or when other healthy options are limited.


Protein shakes to change body composition

Sshakes may also be used primarily to increase protein intake when trying to lose fat and gain lean mass. When you exercise and burn calories, but are also consuming less from your diet, the body starts to break down stored fat – as long as it has enough protein.4

It may sound confusing that gaining mass can lead to weight loss, but the more muscle (lean mass) your body has, the greater amount of energy (calories) it burns. When you’re burning lots of calories during intense workouts, protein shakes not only help your muscles to repair, but also prevent their breakdown and help your body to burn fat instead.3 Using protein powder in addition to exercise that builds muscle can help lead to these long-term body composition changes.5

When should you drink a protein shake for weight loss?

The timing of your protein shake depends on where it fits in with your goals and your planned meals for the day. If the protein shake is designed to replace a meal, you would simply have it at that mealtime. If you are consuming protein to help you gain muscle, it’s best to consume it after your workout, and for up to 24 hours after.5 If you’re using a low-calorie protein shake to feel full and satisfied, it might work best between meals or after a light meal or snack — depending on when you usually feel the hungriest and need to avoid temptation of less-healthy foods.

In addition to the to suppressing ghrelin and slowing from a protein shake, shakes are often high in liquid content. Liquids reach your stomach faster than food, and a shake is typically comprised of at least 8-12 ounces of liquid. The volume of this fills your stomach and can help you to feel satisfied quickly.

Protein shake ideas

If you’re planning a shake to replace a meal, think about including a balance of all the macro- and micronutrients by including some healthy fats and carbohydrates in your shakes too. Here are a few ideas to get you started — two meal replacement smoothies, a post-workout shake, and a diet shake, designed to be used as a snack.


  • Green Protein Meal Replacement Smoothie: Add spinach, berries, and avocado to a blender cup with your favorite protein powder. Mix with water, milk (for more protein), or a non-dairy milk and blend for a cool smoothie.


  • Banana Nut Meal Replacement Smoothie: Add frozen banana and a spoonful of peanut or almond butter to your favorite protein powder flavor (try chocolate!), add milk or non-dairy milk, and blend until smooth. For an extra boost of protein, add some Greek yogurt.


  • Post-workout shake: If you have a very intense workout and need to refuel after a workout, mix the protein powder with water and consume within 30 minutes of your training. Based on how hard you worked, you might want to choose a protein powder with some carbohydrates to help rebuild your muscle’s energy stores while they repair and grow.


  • Diet shake: Mix a low carb, low calorie protein powder with a low-calorie liquid, keeping the fat and carbohydrate counts low. This is a filling snack to help resist overeating without consuming too many calories. This can be as simple as adding a scoop of protein powder to water and mixing it in a blender bottle, or adding some flavored protein powder to leftover coffee and blending with ice for a satisfying frozen coffee treat.

Weight loss shakes for women

While many research studies focus on protein shake supplements for men, the benefits can also apply to women who are trying to lose weight. Protein will similarly affect ghrelin levels and slow digestion in women, just like the studies on male subjects have displayed.

However, women are typically smaller in total body mass than men and may benefit from a lower calorie protein supplement, since they would need fewer total calories throughout the day, especially when trying to lose weight. Remember that your protein powder should only be part of your overall healthy diet pattern.


Take home message

Protein shakes can help with weight loss in a variety of ways — by helping to replace high-calorie meals, to keep you full between meals and prevent overeating, or to help build muscle and burn fat from your workouts.4 Protein lowers the levels of the hunger hormone ghrelin, telling the brain that you’re less hungry.

Protein powders can help anyone to maximise the results of a healthy diet and exercise habits, as well as see the weight loss results you’re hoping for. While some pre-made protein shakes are available on the market, be careful to read the labels and check what other ingredients are included. To have the most control over what goes into your protein shakes, make them yourself at home.

Our articles should be used for informational and educational purposes only and are not intended to be taken as medical advice. If you’re concerned, consult a health professional before taking dietary supplements or introducing any major changes to your diet.

  1. Dong, J. Y., Zhang, Z. L., Wang, P. Y., & Qin, L. Q. (2013). Effects of high-protein diets on body weight, glycaemic control, blood lipids and blood pressure in type 2 diabetes: meta-analysis of randomised controlled trials. British Journal of Nutrition110(5), 781-789.
  2. Giezenaar, C., van der Burgh, Y., Lange, K., Hatzinikolas, S., Hausken, T., Jones, K., … & Soenen, S. (2018). Effects of substitution, and adding of carbohydrate and fat to whey-protein on energy intake, appetite, gastric emptying, glucose, insulin, ghrelin, cck and glp-1 in healthy older men—A randomized controlled trial. Nutrients10(2), 113.
  3. Giezenaar, C., Hutchison, A., Luscombe-Marsh, N., Chapman, I., Horowitz, M., & Soenen, S. (2018). Effect of age on blood glucose and plasma insulin, glucagon, ghrelin, CCK, GIP, and GLP-1 responses to whey protein ingestion. Nutrients10(1), 2.
  4. Leidy, H. J., Clifton, P. M., Astrup, A., Wycherley, T. P., Westerterp-Plantenga, M. S., Luscombe-Marsh, N. D., … & Mattes, R. D. (2015). The role of protein in weight loss and maintenance. The American journal of clinical nutrition101(6), 1320S-1329S.
  5. Samal, J. R. K., & Samal, I. R. (2018). Protein Supplements: Pros and Cons. Journal of dietary supplements15(3), 365-371.

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Claire Muszalski

Claire Muszalski

Registered Dietitian

Claire is a Registered Dietitian through the Academy of Nutrition and Dietetics and a board-certified Health and Wellness Coach through the International Consortium for Health and Wellness Coaching. She has a Bachelor of Science in Biology and a Master’s degree in Clinical Dietetics and Nutrition from the University of Pittsburgh.

Talking and writing about food and fitness is at the heart of Claire’s ethos as she loves to use her experience to help others meet their health and wellness goals.

Claire is also a certified indoor cycling instructor and loves the mental and physical boost she gets from regular runs and yoga classes. When she’s not keeping fit herself, she’s cheering on her hometown’s sports teams in Pittsburgh, or cooking for her family in the kitchen.

Find out more about Claire’s experience here.

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