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People drink protein shakes for multiple reasons, including muscle gain, weight loss, and injury recovery.

While many foods provide you with a lot of protein — such as eggs, meat, poultry, milk, and legumes — protein shakes and powders have become a popular, high-quality source of this nutrient.

If you wonder whether these shakes will give you the results you want, you’re not alone.

This article focuses on the effectiveness of protein shakes for muscle gain and weight loss.

According to the Food and Drug Administration (FDA), dietary supplements are products that contain a dietary ingredient, such as vitamins, minerals, amino acids, and herbs (1).

In this case, protein shakes provide amino acids, also known as the building blocks of proteins.

Dietary supplements come in many forms, from powders to capsules to liquids. While you may find ready-to-drink protein shakes in liquid form, you can also purchase protein supplements in powder form.

Many types of powdered protein supplements are available from either animal- or plant-based sources.

For instance, the most popular animal-based protein powders are whey and casein, both usually derived from cow’s milk. However, if you have a milk allergy, egg white protein may be a suitable choice.

As for popular plant-based proteins, you can take your pick from soy, pea, hemp, or rice protein.

Lastly, as their name implies, dietary supplements are meant to help you complete or enhance your diet.

Overall, protein shakes may come in handy when you don’t have high-quality protein sources available or simply can’t reach your daily protein needs through food alone.

Summary

Protein shakes are a dietary supplement. They may help complete or enhance your diet if you need an extra boost to meet your daily protein target.

Protein shakes were initially consumed by athletes and gym enthusiasts who wanted to increase their muscle mass and improve their performance.

In fact, combining protein shakes with resistance training may promote muscle growth and enhance physical performance and recovery (2, 3, 4, 5).

This happens because resistance training stimulates muscle protein synthesis, as does an increased intake of high-quality protein (6, 7).

As mentioned before, protein shakes provide amino acids that are easily absorbed by your body. Researchers believe that their intake increases amino acid levels in the bloodstream, which in turn triggers a more significant response for muscle synthesis (8, 9, 10).

What’s more, studies suggest that protein shakes help retain and may promote muscle gain even if you’re following a weight loss diet (11, 12).

For example, one study in 40 men showed that those following a high protein diet achieved via protein supplements lost more fat mass and increased their muscle mass when they added strength and cardio training, compared with the control group (11).

Similarly, another study in 40 healthy adults determined that whey protein supplements lessened the expected decrease in muscle protein synthesis after weight loss (12).

Therefore, protein shakes may help you achieve your fitness goals, whether you want to lose fat or gain muscle.

Summary

Protein shakes promote muscle gain and improve performance and recovery. They also prevent muscle loss and may even help increase muscle mass during weight loss.

High protein diets activate different pathways that promote weight loss, and drinking protein shakes may help you increase your daily protein intake (13).

Increase feelings of fullness

Multiple hormones are involved in appetite stimulation and control, including peptide tyrosine-tyrosine (PYY), glucagon-like peptide 1 (GLP-1), and ghrelin. Protein seems to influence their production.

Both PYY and GLP-1 are hunger-reducing hormones, and studies show that high protein diets increase levels of each after a meal (14, 15 16, 17, 18).

PYY and GLP-1 act by reducing your appetite, and GLP-1 also delays the emptying of your stomach’s contents. Thus, both hormones lead to increased feelings of fullness (19).

What’s more, evidence suggests that protein may also reduce levels of ghrelin, a hormone that stimulates appetite (20, 21).

While most studies use food, these appetite-controlling effects have also been seen when testing supplements (22).

For example, one study in 18 women determined that drinking a whey protein beverage lowered ghrelin levels and increased PYY and GLP-1 levels, compared with the control group (23).

Boosts your metabolism

High protein diets also increase energy expenditure — the calories you burn — in two different ways.

First, your body burns more calories by metabolizing protein than carbs or fat. This metabolic response to food is known as diet-induced thermogenesis (DIT) (24, 25).

DIT indicates the amount of energy needed to metabolize each nutrient relative to the number of calories ingested. Its values for protein range from 15–30% in contrast to 5–10% for carbs and 0–3% for fat (24).

Second, high protein diets stimulate gluconeogenesis — the process of producing glucose from proteins or fats in the absence of carbs — which is believed to burn extra calories in the process (26, 27).

In fact, one study in 10 healthy men reported a higher energy expenditure in a high protein diet compared with the control condition, determining that 42% of the increase was due to gluconeogenesis (28).

Therefore, increasing your protein intake through protein shakes and powders might help you take advantage of these metabolic effects.

May help you lose belly fat

High protein diets are known to promote fat oxidation and fat loss (29, 30, 31, 32).

Evidence suggests that increasing your protein intake from high-quality sources, such as protein shakes, may be associated with fat loss from your midsection, also called visceral or abdominal fat (33, 34).

Losing fat from around your waist is especially important. Increases in visceral or abdominal fat cause chronic inflammation, which has been linked to insulin resistance and heart disease (33).

In one study in 37 women, those who consumed an extra 40 grams of whey protein per day, showed a small reduction in abdominal fat compared with those who received a lower protein-quality supplement (33).

Similarly, a 23-week study determined that those who consumed an extra 56 grams of whey protein per day had lower body weight by 4 pounds (1.8 kg) and lower body fat by 5 pounds (2.3 kg), compared with the control group (34).

Summary

Consuming protein shakes and powders as part of a high protein diet may help control your appetite, increase the calories you burn, and lose belly fat, indicating they may be effective for weight loss.

Protein shakes and powders make a helpful addition to your weight loss journey. However, there’s more to losing weight than just upping your protein intake.

If you want to lose weight, you need to induce a negative energy balance, meaning that you should burn more calories than you consume. This is also known as a calorie deficit (24).

There are three different ways to achieve a calorie deficit — either by consuming fewer calories, expending more calories by increasing your physical activity, or a mixture of both (35, 36, 37).

While a higher protein intake allows you to eat fewer calories without feeling as hungry, protein still contains calories that contribute to your daily total — 4 calories per gram, to be precise.

Thus, eating too much of it may take you out of your calorie deficit and even contribute to a calorie surplus, which would either hinder your weight loss efforts or lead you to gain weight (38).

For example, one study determined that people who ate a high protein diet that increased their calorie intake by 40% gained both body weight and fat (39).

Therefore, even if protein shakes are a helpful weight loss tool, you should still have your “calories in versus calories out” equation in mind.

Since increasing your physical activity helps you boost your calories expended, you can try practicing either resistance training or aerobic exercise (cardio), which includes walking, jogging, swimming, dancing, and cycling.

However, research suggests that a combination of both is the most efficient way to lose weight, as cardio helps achieve a more pronounced weight reduction while resistance training helps maintain or improve your muscle mass (40, 41).

Summary

While high protein diets are great for weight loss, overeating protein may still keep you from achieving your desired results.

High protein diets are characterized by a daily protein intake above the Recommended Dietary Allowance (RDA) of 0.4 grams per pound (0.8 grams per kg) (24).

Those who struggle to reach those quantities through food may turn to protein shakes.

However, if you can reach your daily protein requirement through natural sources, protein shakes may be unnecessary.

Some high-quality protein foods include eggs, milk, meat, fish, poultry, and soy.

Additionally, protein shakes tend to be expensive, so if you’re on a budget, eating animal- or plant-based proteins may be more suitable.

Summary

If you can reach your daily protein target by eating enough high-quality protein foods, you may not need to drink protein shakes.

High protein diets are a great weight loss and muscle building strategy, and protein shakes make it easier to increase your protein intake.

Since they may help control your appetite, boost your metabolism, and help you shed some belly fat, protein shakes may be effective for weight loss. Additionally, they help you gain muscle and improve your performance when combined with resistance training.

However, if you eat enough high-quality protein foods throughout the day, taking a protein supplement may be unnecessary.

Also, keep in mind that overeating protein can lead to weight gain.

If you want to give protein shakes a go, you can find many animal- and plant-based protein powders in stores and online to fit your needs.