How protein shakes can help you lose weight and belly fat
Protein is an important nutrient for weight loss. Eating enough protein can boost your metabolism, reduce your appetite and help you lose body fat without breaking down muscle.
Protein shakes are an easy way to add more protein to your diet and have also been shown to help with weight loss.
This article will explain everything you need to know about protein shakes and how they can affect your weight.
What are protein shakes?
Protein shakes are drinks that you can easily prepare yourself by mixing protein powder with water or milk. In addition to liquid and protein powder, other ingredients are often added to improve taste or nutritional values.
Protein shakes are a practical and convenient way to add high-quality protein to your diet, which is particularly beneficial if the rest of your diet does not provide enough high-quality protein.
Although most people don't necessarily need protein shakes to meet their daily protein requirements, these shakes can also be useful if you want to increase your protein intake for specific reasons.
Some of the most popular types of protein powder include
- Whey protein: Whey protein is a fast-absorbing, dairy-based protein that contains all the essential amino acids (1).
- Casein protein: Casein is a slow-absorbing, milk-based protein that contains all the essential amino acids (1).
- Soy protein: Soy protein is a plant-based protein that contains all the essential amino acids. Soy protein also contains isoflavones, which may have additional health benefits. (2).
- Hemp protein: Hemp protein is a plant-based protein that is rich in omega-3 fatty acids but contains relatively small amounts of the essential amino acid lysine.
- Rice protein: Rice protein is a plant-based protein that contains relatively small amounts of the essential amino acid lysine.
- Pea protein: Pea protein is a plant-based protein that contains relatively small amounts of the non-essential amino acids cysteine and methionine (4).
There are also protein powders that contain a mixture of different types of protein. For example, many plant-based protein powders contain a mixture of plant-based proteins whose amino acid profiles complement each other.
Protein shakes reduce hunger and appetite
Protein can reduce hunger and appetite in two primary ways. Firstly, it increases levels of appetite-reducing hormones such as GLP-1, PYY and CCK, while reducing levels of the hunger hormone ghrelin (5, 6, 7, 8, 9).
Secondly, protein helps you feel fuller for longer (10, 11). In one study, a protein-rich breakfast helped subjects eat up to 135 kcal less later in the day (12).
In another study, men on a weight loss diet increased their protein intake to 25% of their total calorie intake. This increase reduced food cravings by 60% and halved the frequency of eating snacks late in the evening (13).
Increasing protein intake from 15% to 30% of total calorie intake helped subjects in another study to eat 441 kcal less per day without actively trying to reduce their portions (14). In addition, at the end of the 12-week study, these subjects had lost an average of 5 kilograms (14).
Protein shakes can be a convenient way to add extra protein to your diet. However, you should keep in mind that too much protein can ultimately lead to excessive calorie intake.
Another study found that shakes that provided 20 to 80 grams of protein, regardless of the actual amount of protein they contained, all reduced hunger by 50 to 65% (15). So if you want to lose weight, 20 grams of protein per shake seems to be enough to reduce hunger.
Summary: Protein may reduce appetite by influencing hunger hormones. It can help you feel fuller for longer, which can help you eat less and lose body fat.
Protein shakes can increase your metabolic rate
A high protein intake can boost your metabolism, helping you burn a few more calories each day (16, 17). This is at least partly due to the fact that a high-protein diet - especially when combined with strength training - can help you build muscle. This can increase your metabolic rate, as muscle burns more calories than fat.
In one study, obese subjects were given either 200 or 0 grams of extra protein per week. Those who received extra protein gained 1.3 kilos more muscle during a 13-week training program (18).
In another study, the scientists gave their subjects a combination of food and shakes containing either 1.2 grams or 2.4 grams of protein per kilogram of body weight. After six weeks, the subjects who had received 2.4 grams of protein had built up 1.1 kilograms more muscle and lost 1.3 kilograms more fat (19).
However, it should be noted that the ability to build muscle during a weight loss diet may depend on the amount of muscle you already have (20).
Protein can also increase metabolic rate due to the calories needed to digest and metabolize dietary protein. This is also known as the thermic effect of food (TEF for short). Thus, during the digestion of protein, 15 to 30% of the calories consumed in the form of protein are burned, whereas this value is only 10% for carbohydrates and in the range of 0 to 3% for fat (21).
Summary: Protein helps to increase the metabolic rate because a lot of energy needs to be expended for digestion and metabolism. Protein also helps build muscle and muscle burns more calories than fat.
Protein shakes can help you lose weight and belly fat
Scientists generally agree that high-protein diets can help you lose more fat - especially belly fat (22, 23).
In one study, subjects who followed a diet that provided 25% of calories in the form of protein lost 10% more belly fat over 12 months than subjects who ate half as much protein (24).
In another study, subjects who consumed an additional 56 grams of whey protein daily had lost 2.3 kilos more at the end of the 23-week study without consciously changing their diet (25).
Another study compared the effects of different weight loss diets. The subjects who consumed more protein lost an average of 14.1 kilos in weight within 3 months - 23% more than the subjects who consumed less protein (26).
In a final study, subjects who consumed 30% of their calories in the form of protein lost 3.7 kilos more weight than subjects who consumed only 15% of their calories in the form of protein (13).
Summary: Protein shakes are a convenient way to increase daily protein intake, which can increase fat loss, especially around the midsection.
Protein shakes can prevent muscle loss and a reduction in metabolic rate
Weight loss is often accompanied by a loss of muscle mass, which can reduce metabolic rate and daily energy requirements. This makes it easier to regain the lost weight (and more) once the diet ends.
A high protein intake combined with strength training can help prevent some of this muscle loss and reduction in metabolic rate (27, 28, 29).
In fact, studies report that the metabolic rate of subjects on a weight loss diet that provided 36% of calories in the form of protein decreased less than those on a diet that provided only half that amount of protein (30).
Scientific research shows that a daily protein shake as part of a weight loss diet can be up to 3.5 times more effective in maintaining muscle mass (31).
A study conducted with athletes compared weight loss diets that included either 35% or 15% of calories in the form of protein. Both diets helped subjects lose about the same amount of fat, but the subjects who consumed more protein lost an average of 38% less muscle mass (32).
A recent study review also notes that weight loss diets that exceed 1 gram of protein per kilogram of body weight per day may help older adults maintain more muscle mass and lose more fat (33).
Summary: Protein shakes consumed during a weight loss diet can help prevent muscle loss and a slowing of the metabolic rate. This is particularly effective when combined with strength training.
Protein shakes can help prevent weight gain after a diet
The effects of protein on metabolism, appetite and muscle mass could also help prevent you from putting back on the fat you worked so hard to lose after a diet.
One study reported that subjects who consumed more protein lost more weight and were able to maintain their new weight better than subjects who consumed less protein. The group with the higher protein intake regained only 9% of the lost weight after the diet, while the low-protein group regained 23% of the lost weight (26).
In another study, subjects who had just completed a weight loss intervention were given a supplement that provided 48.2 grams of protein per day. The subjects who received the supplement felt fuller after meals and had gained 50% less weight after 6 months than the subjects who did not receive the supplement (34).
Another study observed similar results with a supplement that provided only 30 grams of protein, showing once again that more is not necessarily better (35).
Summary: Supplemental protein in the form of shakes or whole foods can help minimize the amount of weight you regain after dieting.
Which type of protein is best?
Different types of protein have different effects on the body. Whey protein, for example, is absorbed faster than casein protein, which can help you feel less hungry in the short term (36).
One study reported that 56 grams of whey protein per day helped overweight and obese subjects lose 2.3 kilos more fat than when using the same amount of soy protein (25). Another study concluded that whey protein is three times more effective than soy protein in maintaining the ability to build muscle during a weight loss diet (31).
However, not all studies agree that whey protein is superior. For example, one study noted that the rapid onset hunger-reducing effects had no impact on the amount of calories consumed during subsequent meals (36).
In addition, several studies report comparable results in terms of fat loss when using whey protein, soy protein, rice protein or egg protein supplements (37, 38).
Another factor that should be considered is the quality of the protein. Whey protein, casein and soy protein contain all the essential amino acids your body needs. Rice protein and hemp protein, on the other hand, only contain small amounts of the essential amino acid lysine and pea protein is low in the non-essential amino acids cystine and methionine.
However, these deficiencies in certain amino acids are unlikely to cause problems as long as these protein shakes are not the only source of protein. In addition, many plant-based protein powders contain a mixture of different protein sources, which means that this mixture contains all the essential amino acids.
Summary: The exact type of protein powder you use in your shake shouldn't make much difference to fat loss, with some studies showing benefits of whey protein.
Dosage and side effects
One shake per day should be a good starting point. It is best to consume this shake, which should contain 1 to 2 scoops of protein, either before or instead of a meal. Preparing this shake with water, ice and perhaps some fruit in a blender is an easy way to make a delicious and satisfying shake.
Side effects such as bloating, stomach cramps and diarrhea can occur if you are lactose intolerant and drink shakes containing whey protein or casein. These symptoms can be avoided if protein powders such as egg protein, pea protein, soy protein or hemp protein, which are not made from milk, are used instead.
In the past, it was often claimed that high-protein diets could have negative effects on kidney and bone health, but more recent research shows that this is not the case.
In fact, high protein intake has never been shown to cause kidney damage in healthy people. However, lower protein diets may be beneficial for people with existing kidney damage (39, 40).
Protein is also an essential nutrient for bone formation and maintenance of healthy bones, and study reviews show that there is no reason to limit protein intake to improve bone health (3. 41).
Most studies report that a protein intake of between 1.2 and 2.2 grams per kilogram of body weight per day provides the most weight loss benefits. This amount of protein represents about 25 to 35% of the calories consumed daily and is generally considered safe and harmless.
Conclusion
Most people can easily consume enough protein without using protein shakes.
These supplements are an easy, safe and delicious way to add extra protein to your diet.
If you are trying to lose weight, then additional protein in the form of shakes can help you feel less hungry, lose weight faster and reduce the likelihood of weight gain after you stop dieting.
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https://www.healthline.com/nutrition/protein-shakes-weight-loss