Are Protein Shakes Good for Weight Loss? (Risks, Best Types & More)

Weight Loss & Diets | Written by Nathan | Updated on 13 December 2021

With rates of obesity continuously on the rise, many people are seeking ways to lose weight and commonly wonder if protein shakes are good for their weight loss journey. 

The truth is, protein shakes should be a staple in your meal plan since they promote overall health, support weight reduction and building muscle. However, it’s crucial to understand the potential risks of over consumption, which types are best, how to time your protein shakes for maximum results and the fundamentals of how protein works [1] [2]. 

What is Protein?

You’ve probably heard about the importance of protein in your diet, but do you know why?

Proteins are an essential macronutrient that our bodies use to grow, maintain and regulate our various tissues, organs and bodily chemicals. Some call it the building blocks of life, but we call it the building blocks of gains. 

Furthermore, protein is made from twenty-plus amino acid building blocks that can be found in many plants and animals [3,4]. Nine of the amino acids are known as essential amino acids because our bodies cannot make them on their own and must come from the foods we eat [3,4].

Much like letters forming words, amino acids are arranged in millions of different sequences to form proteins [5].  Proteins fold into specific shapes based on the number (can be 300 or more) and order of amino acids and this shape helps to determine the function of the protein [5].  Some proteins form the structure of our cells and tissues like muscles, while others form enzymes and hormones [5].

It is important for us to include protein in our diets because our bodies continuously build and repair proteins (protein synthesis), and there is a constant demand for amino acids to complete this process [5]

Why is Protein Helpful for Weight Loss?

In comparison to other macronutrients in your diet such as carbs and fats, dietary proteins have been shown to reduce appetite by increasing a feeling of fullness and delaying the return of hunger [9]. Additionally, dietary protein can decrease the amount of energy (calories) consumption needed [9] and promotes the retention of lean muscle mass [2].

Appetite Suppression

Studies have shown that foods high in protein reduce food intake at a later meal more than carbohydrates or fats, and provide stronger feelings of fullness immediately after consumption [10]. When you feel fuller longer, you have less of an urge to eat, which in turn reduces the amount of calories you consume, promoting weight loss.  The most effective methods for losing weight focus primarily on achieving an energy deficit [11]. This is accomplished by consuming fewer calories than we are burning on a daily basis.

Recent research has discovered a group of receptors in our bodies that are able to recognize amino acids, which can impact how digestion is regulated [12]. Some of these receptors are located within our digestive tract and they secrete two gut hormones, the glucagon-like peptide 1 (GLP-1) and the peptide tyrosine tyrosine (PYY) [12].  Whey protein specifically has been shown to increase circulating levels of GLP-1 and PYY gut hormones causing an appetite-suppressant effect [12].  

Lean Muscle Retention

A high-protein diet is also known to promote reduction of body weight and fat mass, while maintaining lean muscle mass [2]. Diets that have been proven to promote weight loss are those that restrict the amount of calories that are consumed. It is important to increase protein intake when losing weight because it has been shown to conserve lean body mass and promote losing weight primarily as adipose tissue that stores fat [10,13].

Healthy Metabolism to Lose Weight

The process of digesting protein also leads to the stimulation of many physiological and metabolic responses known to reduce feelings of hunger [10]. Diets that have more protein allow for greater energy expenditure, when compared to diets with less protein [14].

An article in the American Journal of Clinical Nutrition also reports that higher protein diets prevent a decline in resting energy expenditure (REE) during weight loss [2].

Additionally, some studies have begun to prove that diets that emphasize calorie restriction are successful in promoting improvements in metabolism. The digestion process of protein impacts your body’s metabolism, but consuming certain sources of protein can also help you to reduce your caloric impact, providing a dual-benefit solution.

How Much Protein Do I Need?

There are a lot of factors that determine the amount of protein you should consume, and this is a topic that is highly debated.  Your weight, gender, level of physical activity and body composition goals all inform the amount of protein your body needs.

One of the main methods used to measure how much protein your body actually uses is a process called nitrogen balance [6].  When you consume protein, nitrogen also enters your body and as proteins break down, the nitrogen exits the body in your urine [6.1]. We can tell that you’ve consumed the right amount of protein when the amount of nitrogen consumed is equal to the amount of nitrogen that exits your body [6].

Based on this process, the National Academy of Medicine has determined that the Recommended Daily Allowance (RDA) for the average adult is 0.8 grams per kg of body weight (.36 grams per pound) [6].  For example, a person who weighs 180 pounds should consume at least 63 grams of protein per day. If you are focused on losing weight, though, you should increase the amount of protein you are consuming in your diet.

The RDA is the amount needed to maintain normal bodily function with a moderate activity level. Athletes and bodybuilders, though, need to consume more protein to build muscle. Studies have shown that strength training athletes with more experience become more efficient with protein utilization, so they must consume greater amounts of protein [6].  

A summary of various protein needs based on nitrogen balance determined that even for athletes, anything above 1.8 grams of protein per kg of body weight did not provide significant results in muscle gains. Recent research has also determined that it may even be dangerous to consume too much protein [7].  We will further discuss the risks and dangers of too much protein later in the article.

Protein Sources for your Diet

To lose the most weight, it is important to consider the types of protein you are using in your diet and where they come from in addition to the quantity of the protein consumed. Also, be sure to examine the “protein package” you are consuming, which is everything else that comes alongside protein when we eat it including the different fats, fiber, sodium, etc. [4].

Protein from Food

Many diets that are designed for healthy weight loss encourage you to restrict your calories, while also emphasizing the role that macronutrients play in getting necessary nutrition [15]. The National Academy of Medicine considers anywhere from 10% to 35% of calories per day coming from protein as an acceptable protein intake range [4]. 

However, as reported by the Harvard T.H. Chan School of Public Health, it is difficult to maintain a healthy high protein diet that is also low in calories because many foods that are great sources of protein also come with a high caloric content or are high in saturated fat or sodium.  For example, a 4-ounce sirloin steak has about 33 grams of protein, however it also has about 5 grams of saturated fat [4].

If it is important for you to get the protein in your diet from food, it may be best to focus on plant-based protein sources. Protein from plants such as legumes, nuts, seeds and whole grains, tends to be lower in saturated fat, contains no cholesterol, and provides fiber and other healthy nutrients [3,4].

Protein Powder Supplements

Powdered protein comes from all sorts of places like eggs, milk or plants like soybeans and peas. Here is a breakdown of popular types of protein that can be found in many protein powders on the market today:

  • Whey: is protein that’s derived from cow’s milk and makes up about 20% of all the protein found in dairy milk [16]. Whey protein is the water-soluble part of milk that is characterized as a “fast” digestible protein.  Whey protein includes all 22 amino acids]. In comparison to casein, whey is better at curbing hunger and limiting food consumption [9]. Research has also shown that whey may be especially effective for building muscle mass because of its faster digestion [16].
  • Casein: Casein also comes from cow’s milk and makes up the other 80% of the milk proteins [16]. Casein contains all amino acids that are considered essential and is not soluble in water. It is digested more slowly than whey, and some studies have shown it is useful to lose weight because it helps you feel full and even more so if consumed before fasting [16].
  • Soy: Soy and it’s protein is oftentimes avoided in the fitness community due to it’s suspected effects on hormones. In contrast to many other proteins from plants, soy protein contains a full profile of of all nine amino acids that are essential [16]. Soy protein is commonly used by people who are vegan or have milk sensitivities. One study examined the effectiveness of soy protein and discovered protein from soy was more effective than casein, but not as effective as whey protein when it comes to protein synthesis [16]. 
  • Pea: Pea protein is a healthy substitute and contains 8/9 amino acids that are essential. Pea protein can be used by those who have allergies or dairy sensitivities and can even be found as an added ingredient in some almond milk [16].
  • Hemp: Hemp protein is a favorite among the vegan community since it has healthy omega 3’s even though it lacks some amino acids. Specifically lysine and leucine [16].

What Makes a Good Protein Shake?

Most diets and other weight loss interventions have the primary goal of changing behaviors and lifestyles [19]. If you’ve come to the conclusion that protein shakes are good for weight loss, then it’s important to ensure that it is something that you can continue long-term and create as a new healthy habit in your life.  Here are some things to consider when deciding on the best protein shake for you to lose weight:

  • Do you have any food allergies or sensitivities? Answering this question will help you to determine if you should choose milk-based or plant-based proteins.
  • How much time do you have to dedicate to making protein shakes?  Your schedule will inform whether you can commit to making your own shakes or if the grab-and-go format may be good for you.
  • Are there other nutrients that are missing from your diet?  In addition to protein, dietary fiber is known to promote weight loss [8]. If you’re not getting enough fiber from the foods you eat, you may want to plan to add some leafy greens like kale or spinach to your protein shakes as added benefits.
  • What are your weight-loss goals? Reduced calorie intake has been shown to promote weight loss [15], so if you are attempting to lose a significant amount of weight, it may be beneficial to consider replacing one of your meals each day with a protein shake.

In addition to these questions, it is also important to be aware of the risks and side effects that may be present from consuming protein shakes.

Timing of Drinking Protein Shakes

As discussed in our article about protein timing, many people over time have assumed that the best time to consume protein shakes is immediately after a workout. A new study from the U.S. National Library of Medicine, though, debunks this myth and reveals that when you consume protein doesn’t impact your overall nutrition.

A study specifically about building muscle explored whether consuming protein immediately after a workout or after a two-hour delay had a more significant impact. There was a slight difference in strength when protein was consumed right after a workout, but the difference is negligible [5]. However, another study has shown if you consume protein right before in addition to right after a workout, there may be additive effects on protein synthesis [5].

Protein and Physical Activity

It is advised for the average adult to consume 7 grams of protein for every 20 pounds of body weight. However, if you are engaging in strenuous exercise with the goal of building and maintaining muscle mass, the International Society of Sports Nutrition recommends a daily protein intake of 1.4 – 2.0 g/kg of body weight [16].

This increase in protein helps to optimize muscle protein synthesis which is required for muscles to grow and recover [16].

Overall, for people deemed to be overweight or obese, losing body weight is seen as a positive contributor to health. However, this can be detrimental if muscle loss occurs rather than fat loss [13].  Proteins can be broken down much more easily then they can be synthesized, but studies have shown that a high protein diet can promote protein synthesis and counter losing muscle mass.

One study in particular determined that a very low calorie, high protein diet can improve body composition and preserve muscle mass while decreasing fat mass [13].

Supplementing specifically with whey protein for individuals who are overweight or obese has been shown to decrease body fat mass and improve overall metabolism. Consuming whey protein, while also restricting calories and engaging in regular exercise can cause favorable results for maintaining fat free mass [13].

Based on this, it can be deduced that adding physical activity to the consumption of protein shakes is good because it enhances the weight loss benefits of adequate protein.

Risks and Side Effects of Protein Shakes

Most dietary supplements, including protein powders, are not regulated by the U.S. Food and Drug Administration [4]. This means that they are not reviewed for safety and often contain ingredients other than protein or heavy metals.

Check the Ingredients

When choosing which protein powder that is most healthy for you, be sure to carefully examine the nutrition information and ingredient labels and be aware of added vitamins and minerals, added sugars and artificial thickeners or flavors [4]. However, you also should be careful of artificial sweeteners that may be present in diet protein shakes or “skinny” versions of traditional protein shakes.

If you are consuming protein shakes for the purpose of weight loss, it is a good idea to monitor the amount of calories and sugar contained in your pre-made protein shake or protein powder.

Dangers of Too Much Protein

While the benefits of protein are abundant, it is important to ensure you are not exceeding the amount of protein that your body is able to use [7].  Here is a breakdown of some of the most significant risks:

Weight Gain: If protein is consumed while also eating a calorie surplus, excess protein can be converted to fat [5]

Calcium Loss: If there is too much protein in your diet, this can increase the acid in your body fluids. In order to buffer this challenge, your kidneys and skeleton respond and reabsorb bone, which reduces the calcium in your body [7].

Kidney Stones: In addition to calcium loss, the buffering effect of calcium in the body, can also form calcium kidney stones [7].

Coronary Heart Disease: If a large portion of your protein intake comes from red meat or processed meat, this has been shown to increase risk of coronary heart disease because of increased levels of saturated fat and cholesterol [7]

Cancer: Red meat and processed meat have also been linked to an increased risk for cancer, especially colon cancer [7]

If you are concerned, please discuss how much protein you should consume with your doctor or follow the USA RDA recommendations. Of course, if you are an athlete looking to build muscle, you may need more than that. 

Environmental Impact

On another note, it is also important to think of the global impact consumption of protein products has on agriculture and environmental factors. Different foods affect human health in a variety of ways, and similarly they can have different impacts on the environment [4]. It’s no secret that dairy products have a larger carbon footprint than vegan products, so you may want to consider this when choosing your next protein powder. 

Conclusion

Protein is an essential macronutrient that is a major component of a healthy and nutritious diet. Protein is necessary for several important bodily functions, however there is much debate about the best ratio of protein to consume in relation to your overall caloric intake and if the risks of over consumption. Additionally, there are many sources of protein that have a variety of benefits and side effects depending on your body composition and goals.

A quick and efficient method for consuming protein is by drinking protein shakes and yes, they can reduce hunger and helping you feel fuller longer which helps to promote the retention of lean body mass.  As a result of these positive impacts, it has been determined that protein shakes are good for weight loss, as long as it’s not over consumed.

References

[1] Varkevisser, R., van Stralen, M. M., Kroeze, W., Ket, J., & Steenhuis, I. (2019). Determinants of weight loss maintenance: a systematic review. Obesity reviews: an official journal of the International Association for the Study of Obesity, 20(2), 171–211. https://doi.org/10.1111/obr.12772

[2] Leidy, H., Clifton, P., Astrup, A., Wycherley, T., Westerterp-Plantenga, M., Luscombe-Marsh, N., Woods, S., Mattes, R. (2015). The role of protein in weight loss and maintenance. The American Journal of Clinical Nutrition, 101(6),  1320S–1329S. https://doi.org/10.3945/ajcn.114.084038

[3] National Institute on Aging. (n.d.) Important nutrients to know: Proteins, carbohydrates, and fats. Retrieved from ​​https://www.nia.nih.gov/health/important-nutrients-know-proteins-carbohydrates-and-fats

[4] Harvard School of Public Health. (2021). What should you eat: Protein. The Nutrition Source. Retrieved from https://www.hsph.harvard.edu/nutritionsource/what-should-you-eat/protein/

[5] EUFIC: Food Facts for Healthy Choices. (2019). What Are Proteins and What Is Their Function in the Body? What’s In Food? 2 December 2021. Web. https://www.eufic.org/en/whats-in-food/article/what-are-proteins-and-what-is-their-function-in-the-body

[6] Wilson, J., & Wilson, G. J. (2006). Contemporary issues in protein requirements and consumption for resistance trained athletes. Journal of the International Society of Sports Nutrition, 3(1), 7–27. https://doi.org/10.1186/1550-2783-3-1-7

[7] Delimaris I. (2013). Adverse Effects Associated with Protein Intake above the Recommended Dietary Allowance for Adults. ISRN nutrition, 2013, 126929. https://doi.org/10.5402/2013/126929

[8] Tischmann, L., Drummen, M., Gatta-Cherifi, B., Raben, A., Fogelholm, M., Hartmann, B., Holst, J. J., et al. (2019). Effects of a High-Protein/Moderate-Carbohydrate Diet on Appetite, Gut Peptides, and Endocannabinoids—A Preview Study. Nutrients, 11(10), 2269. MDPI AG. Retrieved from http://dx.doi.org/10.3390/nu11102269

[9] Pal, S., Radavelli-Bagatini, S., Hagger, M. et al. (2014). Comparative effects of whey and casein proteins on satiety in overweight and obese individuals: a randomized controlled trial. Eur J Clin Nutr 68, 980–986. https://doi.org/10.1038/ejcn.2014.84

[10] Anderson, G., Moore, S. (2004). Dietary proteins in the regulation of food intake and body weight in humans. The Journal of Nutrition, 134(4), 974S–979S. https://doi.org/10.1093/jn/134.4.974S

[11] Miketinas, D. C., Bray, G. A., Beyl, R. A., Ryan, D. H., Sacks, F. M., & Champagne, C. M. (2019). Fiber Intake Predicts Weight Loss and Dietary Adherence in Adults Consuming Calorie-Restricted Diets: The POUNDS Lost (Preventing Overweight Using Novel Dietary Strategies) Study. The Journal of nutrition, 149(10), 1742–1748. https://doi.org/10.1093/jn/nxz117

[12] Rigamonti, A. E., Leoncini, R., De Col, A., Tamini, S., Cicolini, S., Abbruzzese, L., Cella, S. G., & Sartorio, A. (2020). The Appetite-Suppressant and GLP-1-Stimulating Effects of Whey Proteins in Obese Subjects are Associated with Increased Circulating Levels of Specific Amino Acids. Nutrients, 12(3), 775. https://doi.org/10.3390/nu12030775

[13] Simonson, M., Boirie, Y., & Guillet, C. (2020). Protein, amino acids and obesity treatment. Reviews in endocrine & metabolic disorders, 21(3), 341–353. https://doi.org/10.1007/s11154-020-09574-5

[14] Lejeune, M., Westerterp, K., Adam, T., Luscombe-Marsh, N., Westerterp-Plantenga, M. (2006). Ghrelin and glucagon-like peptide 1 concentrations, 24-h satiety, and energy and substrate metabolism during a high-protein diet and measured in a respiration chamber. The American Journal of Clinical Nutrition. 83(1), (89–94). https://doi.org/10.1093/ajcn/83.1.89

[15] Balliett, M., Rasmussen, O., & Burke, J. R. (2011). Effects of tea combined with high-protein meal replacement shakes on anthropometric measurements, lipid profiles, cellular biochemistry, neurochemistry, and microbial metabolism: a prospective observational study. Journal of chiropractic medicine, 10(4), 272–282. https://doi.org/10.1016/j.jcm.2011.06.005

[16] Workout Supplements. The Nutrition Source. Harvard School of Public Health. Retrieved from https://www.hsph.harvard.edu/nutritionsource/workout-supplements/

About the Author

Nathan

Nathan has been a fitness enthusiast for the past 12 years and jumps between several types of training such as bodybuilding, powerlifting, cycling, gymnastics, and backcountry hiking. Due to the varying caloric needs of numerous sports, he has cycled between all types of diets and currently eats a whole food diet. In addition, Nathan lives with several injuries such as hip impingement, spondylolisthesis, and scoliosis, so he underwent self-rehabilitation and no longer lives with debilitating pain.