Protein shakes have become increasingly popular as a convenient way to supplement protein intake, particularly for weight loss and muscle gain. Following a protein shake diet encourages weight loss by curbing appetite and reducing the total calories a person consumes in a day. While they offer potential benefits, it's crucial to understand both the advantages and potential risks associated with relying heavily on protein shakes.
What are Protein Shakes?
Protein shakes are drinks made with protein powder. They come in a variety of flavors. You can make them with protein powder that you mix with water, milk, or another liquid, or you can buy them in ready-to-drink form. These shakes are typically made from protein powders, which are powdered forms of protein that come from plants (soybeans, peas, rice, potatoes, or hemp), eggs, or milk (casein or whey protein). One serving of most protein shakes has between 10 and 30 grams of protein, which usually comes from dairy, eggs, or plants. The powders may include other ingredients such as added sugars, artificial flavoring, thickeners, vitamins, and minerals.
Potential Benefits of a Protein Shake Diet
Weight Loss: Replacing meals with protein shakes may help you lower your daily calories, which can help you lose weight. Since protein helps you feel full for longer, having more of it may mean you’re likely to eat less throughout the day. Protein shakes can be a convenient way to reduce overall calorie intake, which is essential for weight loss. A 2016 meta-analysis linked protein consumption to increased feelings of fullness. People who include enough protein in their diets may therefore have fewer food cravings and eat less.
Muscle Building and Maintenance: Protein is essential for building and maintaining muscle, bone strength, and numerous body functions. Protein contains amino acids that support muscle growth, and having more muscle helps you burn more calories. Athletes also drink them to help build muscle, and these shakes might help you if you just need a little extra protein, especially if you're a vegetarian or vegan. Protein shakes can help maintain muscle mass in older people. People need extra protein as they age - 0.6 gram per pound of body weight per day, or about 90 grams for a person weighing 150 pounds. It may be hard to get that much from food alone.
Convenience: Protein shakes are a fast and convenient source of protein. Adding protein powder to a glass of milk or a smoothie may seem like a simple way to boost your health. They offer a quick and easy way to increase protein intake, especially for those with busy lifestyles.
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Nutrient Boost: Manufacturers typically fortify protein shakes with a range of vitamins and minerals. They may also contain fruits, vegetables, and other nutrients.
Help with wound healing: If you've had an injury or are planning to have surgery, a protein shake with whey protein can help to repair your body's tissues.
Potential Risks and Considerations
Nutritional Deficiencies: Meal replacement shakes should not completely replace healthful, balanced diets. This is because it is difficult to get every nutrient from a single food source. A well-balanced diet should always include an appropriate amount of protein, nutrient-dense carbohydrates, and healthful fats. Furthermore, a body that does not receive enough nutrients may experience problems with metabolism. This may slow or disrupt a weight loss plan. In fact, one 2015 study found that people who eat a varied diet are less likely to have obesity.
Digestive Issues: When you drink them as part of a balanced diet, protein shakes can support good health. But some people may have side effects like gas, bloating, diarrhea or cramps: If you’re lactose intolerant, some whey protein shakes may irritate your stomach. Large servings can also cause constipation and nausea. Look for nondairy shakes instead.
Added Sugars and Calories: Some protein powders have little added sugar, and others have a lot (as much as 23 grams per scoop). Some protein powders wind up turning a glass of milk into a drink with more than 1,200 calories. The risk: weight gain and an unhealthy spike in blood sugar. Some protein shakes also use large quantities of sweetener to improve flavor, which can trigger blood sugar spikes. Since protein has calories, consuming too much can make it harder to lose weight.
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Toxins and Contaminants: Earlier this year, a nonprofit group called the Clean Label Project released a report about toxins in protein powders. Researchers screened 134 products for 130 types of toxins and found that many protein powders contained heavy metals (lead, arsenic, cadmium, and mercury), bisphenol-A (BPA, which is used to make plastic), pesticides, or other contaminants with links to cancer and other health conditions. Some toxins were present in significant quantities.
- Heavy Metals: We purchased 15 protein powders and drinks mainly in the New York metro area or online and tested multiple samples of each for arsenic, cadmium, lead, and mercury. We found that three daily servings of the ready-to-drink liquid EAS Myoplex Original Rich Dark Chocolate Shake provides an average of 16.9 micrograms (µg) of arsenic, exceeding the proposed USP limit of 15 µg per day, and an average of 5.1 µg of cadmium, which is just above the USP limit of 5 µg per day. The samples of Muscle Milk Chocolate powder we tested contained all four heavy metals, and levels of three metals in the product were among the highest of all in our tests. Average cadmium levels of 5.6 µg in three daily servings slightly exceeded the USP limit of 5 µg per day, and the average lead level of 13.5 µg also topped the USP limit of 10 µg per day. The average arsenic level of 12.2 µg was approaching the USP limit of 15 µg per day, and the average for mercury was 0.7 µg, well below the USP's 15 µg-per-day limit. Three daily servings of Muscle Milk Vanilla Crème contained 12.2 µg of lead, exceeding lead limits, and 11.2 µg of arsenic. Cadmium raises special concern because it accumulates in and can damage the kidneys, the same organs that can be damaged by excessive protein consumption. Being exposed simultaneously to a mixture of toxins can also potentially increase health risks, particularly when they target the same organs or systems, as some metals we detected do, according to Harbut.
Kidney and Bone Health: It is also important to avoid consuming too much protein powder in one day. A 2013 review of studies found that consuming more than the daily requirement of protein may lead to problems in the kidneys and bones, as well as increase the risk of cancer.
Lack of Regulation: A protein powder is a dietary supplement. The FDA leaves it up to manufacturers to evaluate the safety and labeling of products. We don't know the long-term effects. As nutritional supplements, protein shakes are subject to fewer regulations than medication in the United States. Consumer Reports argue that marketing materials for these products may also be misleading.
Allergic reactions: An allergy to dairy-based protein can also trigger a rash, swelling, or a runny nose.
Recommended Protein Intake
The Dietary Guidelines for Americans state that an average adult needs about 46 to 56 grams of protein a day. This amount depends on your weight and overall health. The following daily recommendations come from the American College of Sports Medicine and the Academy of Nutrition and Dietetics:
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- The average adult needs 0.8 grams of protein per kilogram of body weight, or 0.36 grams per pound. That means if you weigh 150 pounds, you should have about 54 grams per day. (To calculate your weight in kilograms, divide your weight in pounds by 2.2.)
- Recreational athletics: 1.1 to 1.4 grams of protein for every kilogram of body weight
- Competitive athletes: 1.2 to 1.4 grams of protein for every kilogram of body weight
- Ultra-endurance athletes: up to 2.0 grams per kilogram of weight
- Athletes building muscle mass: 1.5 to 2.0 grams per kilogram of weight daily
Teenage athletes also have different protein needs. Recommendations from the Academy of Nutrition and Dietetics for teenagers are based on pounds of body weight rather than kilograms.
- The average teen needs 0.4 to 0.5 grams of protein per pound of body weight each day.
- Teenage athletes need more - 0.5 to 0.8 grams per pound per day.
The Academy cautions, though, against teens using protein supplements. Too much protein can be hard on your kidneys and can cause dehydration. It's best for teens to get most of their protein from foods.
Choosing the Right Protein Shake
Which protein shake is best for you depends on your protein needs. The protein in powders and shakes is either animal-based or plant-based. Whey protein, which comes from cow’s milk, is one of the most common types. Its fat and protein levels vary, depending on the type of whey. If you want to lose body fat, choose a whey-based shake that's higher in protein, has fewer carbohydrates, and only a little bit of fat. Plant-based proteins, like pea, soy, hemp, and rice, tend to have more fiber and less fat than animal-based protein powders. These are good if you’re trying to build muscle or increase your protein intake.
Since protein shakes and supplements aren’t regulated by the FDA, look for shakes that are certified by a third party like NSF International or Informed Choice, which test ingredients. And check the label for protein content and additives.
Protein shakes use different types of protein in varying amounts. They may include:
- Milk
- Whey
- Casein (a type of dairy protein)
- Egg
- Soy
- Rice
- Pea
- Hemp
Protein consists of amino acids, and the best proteins are “complete.” This means that they contain all nine essential amino acids. Most protein shakes use one or more of the following six varieties:
- whey protein
- casein protein
- egg white protein
- soy protein
- plant protein
- beef protein
When Protein Shakes Can Be Useful
In very specific circumstances, they can be useful. Here are some times they make the most sense:
- When you’re growing. Teens need more protein, especially to fuel their workouts, since their bodies are still growing.
- When you’re starting a workout program. If working out is new to you and you’re trying to build muscle, you’ll need more protein than normal. The same is true when you're starting a workout program that's more intense than your usual one.
- When you’re recovering from an injury. When you're injured, you need extra protein to help your body heal.
- If you’re vegetarian or vegan. A well-balanced plant-based diet can provide all the protein you need.
Alternatives to Protein Shakes
Instead of protein shakes, they recommend eating protein-rich foods such as milk, lean meats, and eggs. McManus says that in certain cases, chemical-free protein powders may be helpful-but only with medical supervision. Otherwise, get protein from whole foods: nuts, seeds, low-fat dairy products (yogurt, milk, cheese), legumes (beans, lentils), fish, poultry, eggs, and lean meat. Food and Drug Administration research suggests that foods such as milk, yogurt, eggs, poultry, and red meats are generally good protein sources that seem to contain little or no cadmium, lead, arsenic, or mercury.
Recommendations for a Safe Protein Shake Diet
To get the most out of a protein shake diet, it is best to talk to a doctor or registered dietitian first. People should only consume one or two protein shakes daily and for a short time only. It is also best to choose a protein shake that fulfills part of a healthful diet. For instance, a person who does not eat many vegetables might choose a meal replacement protein shake that contains vegetables. The best way to enhance weight loss when following a protein shake diet is by eating nutrient-dense, low-calorie foods between shakes.
Keep in mind that the key to losing weight is burning more calories than you consume. Also add physical activity to your daily routine. Aim for about 30 minutes of activity, such as brisk walking, most days of the week. But don't start drinking protein shakes and keep following your usual diet without exercising. Those extra calories will have the opposite effect and cause you to gain weight.