Being overweight or obese puts you at risk of a myriad of medical problems, including diabetes, heart disease, and certain types of cancer (1, 2, 3, 4). Hence, many are investing in different weight loss plans.
Over the past 2 decades, higher-protein diets have been touted as a successful strategy to lose weight. These improvements are thought to be due, in part, to modulations in energy metabolism, appetite, and energy intake.
But what is protein and why should you care? This article takes a look at how protein can naturally help you lose weight, its many types, recommended amount, and other health benefits.
What Are Proteins?
We all know proteins as the main building blocks of our bodies. They are used to make muscles, tendons, organs, and skin. Enzymes, hormones, and neurotransmitters are also made up of protein to serve several important bodily functions. Having said that, can you imagine life without protein?
Proteins are made of amino acids, which are linked together like beads on a string. They form long protein chains, which are then molded into different shapes. Not all amino acids can be produced by our bodies. Hence, must be obtained from our diet. We call them essential amino acids.
Generally speaking, animal protein provides all essential amino acids in the right ratio for you to make full use of them. If you are eating eggs, fish, meat, and dairy on a regular basis, you are more likely to be covered. Animal products offer the highest quality of protein.
If you are a vegetarian and do not eat animal products, getting all the protein and essential amino acids your body requires can be a little more challenging. You will have to get them on other sources such as beans, lentils, tofu, and more. Others try protein shakes and supplements.
How Can Protein Help You Lose Weight Naturally?
Protein can help you lose weight and belly fat through several different mechanisms. Here are the effects of protein on weight loss:
1. It Reduces Appetite and Hunger Levels
Among the three macronutrients, protein is by far the most filling.
Weight is actively regulated by the brain, specifically the hypothalamus (5). For the brain to determine when and how much to eat, it processes several types of information. It receives signals through your hormones, whose level may vary in response to feeding (6).
A higher protein meal can reduce the level of the hunger hormone ghrelin, while boosting the levels of your satiety or appetite-reducing hormones like peptide YY, GLP-1 and cholecystokinin (7, 8, 9, 10).
These effects on appetite are powerful. Evidence showed that an increase in dietary protein from 15% to 30% of energy at a constant carbohydrate intake helped women eat more than 440 fewer calories daily without intentionally restricting anything (11).
By replacing carbs and fat with protein, you can decrease hunger, eat fewer calories, and lose weight.
2. It Boosts Metabolism and Burns More Fat
Eating boosts your metabolism for a short while. That is because your body uses calories to digest and make use of the nutrients in foods. This is known as the thermic effect of food or TEF.
However, not all foods are similar in this regard. Protein is known to have a higher thermic effect, 20-35%, compared to just 5-15% on carbs or fat (12).
High protein intake can significantly boost metabolism. It can likewise help you burn 80-100 more calories daily, on average (13, 14, 15). But one study even showed that you can burn more. People who ate a high-protein diet burned about 260 calories more daily compared to those who had low-protein foods. That is equivalent to 1 hour of moderate-intensity exercise per day (16)!
3. It Cuts Cravings and Lessens Late-Night Snacking
Food craving and hunger are two different things. The former is quite hard to control. It isn’t just about getting your body the required energy and nutrients, it is more of you needing a reward (17).
How can you prevent cravings then? Increasing your protein intake is a good preventive measure. Evidence showed that by increasing protein to 25% of calories, you can reduce your cravings and desires to snack at night by as much as 60% and 50%, respectively (18).
This can be due to an improvement in the function of dopamine, a hormone that is greatly involved in cravings and addiction (19).
4. It Prevents Muscle Loss and Metabolic Slowdown
Weight loss does not always mean fat loss. Muscles can be reduced as well. When trying to slim down, you want to get rid of body fat under your skin and around organs.
Unfortunately, weight loss can have side effects too, including muscle loss and slowed metabolic rate. When these happen, you will burn several hundred fewer calories than you did before you lose some weight. Experts refer to this as “starvation mode (20, 21)”
Increasing your protein intake can help reduce muscle loss and keep your metabolic rate higher as you slim down (22, 23, 24, 25, 26). Strength training can also prevent muscle loss and metabolic slowdown (27, 28, 29). Therefore, a combination of these two can make a perfect fat loss plan.
5. It Makes You Lose Weight Even Without Calorie Restriction
For sure you have heard of the equation, “calories in versus calories out.” Protein actually works equally on both sides of this formula. It reduces calories in and increases calories out. Hence, high protein diets are successful in promoting weight loss, even without intentionally restricting calories or portions (30, 31, 32). You can lose an average of 11 pounds by increasing your protein intake to 30% of calories for over 12 weeks (33).
A high protein diet can also help you remove belly fat that builds up around vital organs (34, 35).
6. It Helps Maintain Weight Loss
Losing weight is not the most important factor. Keeping it off in the long-term is what really matters. Many people who have lost weight end up gaining it back (36).
Good thing, protein can help prevent weight regain. Even a modest increase in your protein intake, approximately 15% to 18%, can help reduce weight regain by as much as 50% (37).
So not only protein can help you shed off pounds, but it can also help you keep it in the long-term.
What Are The Other Health Benefits of Consuming More Protein?
Aside from weight loss and maintenance, proteins can offer you a slew of other health benefits:
1. It Promotes Bone Health
Many are thinking that animal protein isn’t good for the bones because it increases acid load in the body. This causes calcium to leach from the bones to help neutralize acidity.
However, many long-term studies say otherwise. Proteins, including animal protein, offer many benefits for bone health (38, 39, 40). People who eat more protein tend to have better bone mass as they grow older. They are less prone to fractures and osteoporosis (41, 42). This is good news for women, who are at a greater risk of osteoporosis after menopause.
2. It Lowers Blood Pressure
Everybody fears high blood pressure because it is a major cause of heart attacks, strokes, and chronic kidney disease. Interestingly, protein can help you lower blood pressure.
A review of studies showed that increased protein intake can help lower systolic blood pressure by 1.76 mm Hg and diastolic blood pressure by 1.15 mm Hg (43). It can also reduce bad cholesterol and triglyceride levels (44).
3. It Preserves Healthy Kidneys
A lot of people wrongly believe that too much protein can harm the kidneys. While it is true that restricting protein intake can benefit patients with pre-existing kidney diseases, protein does not affect healthy kidneys.
Several studies emphasize that high protein diets have no harmful effects on people without kidney disease (45, 46, 47).
4. It Helps You Recover from an Injury
As the main building blocks of body tissues and organs, protein helps your body repair itself after an injury. Many studies demonstrate that eating a high protein diet after an injury can help hasten recovery (48, 49).
5. It Keeps You Fit As You Age
As you age, your muscles become weaker. In severe cases, you may suffer from age-related sarcopenia, which causes frailty, fractures, and reduced quality of life among the elderly (50, 51).
Aside from staying physically active, consuming more protein can help prevent age-related muscle deterioration and sarcopenia (52).
How Much Protein Is Needed for Weight Loss?
The recommended intake for protein is only 46 and 56 grams for the average woman and man, respectively. This amount is enough to prevent a deficiency but is far from what is needed if you want to lose weight or increase your muscle mass.
If you would notice, most of the studies mentioned above-expressed protein intake as a percentage of calories. They are aiming for protein at 30% of calories for weight loss. You can compute for the grams by multiplying your calorie intake by 0.075. So, that is 150 grams of protein on a 2000 calorie diet.
You can also use your weight to compute for the recommended grams of protein per kilogram. Ideally, you should go for 0.7 to 1 gram of protein per lean mass or 1.5 to 2.2 grams per kilogram.
It is best to spread your protein intake throughout the day. These numbers need not be exact, anything in the range of 25-35% of calories should be helpful.
Which Type of Protein Is Good for Weight Loss?
1. Whey Protein
Who doesn’t know about whey protein? This is probably the most popular powder for gym goers today. It is easily digested and absorbed in the body. Hence, perfect after exercise for recovery.
But aside from its well-known use for building muscles, evidence showed it can also promote weight loss (53, 54). Overweight and obese people who took whey protein lost more weight and gained more muscle mass than those who did not. Significant improvements in blood sugar control, blood pressure, and cholesterol levels were also noted (55).
These weight loss benefits can be attributed to whey protein’s ability to reduce appetite, making you feel full for longer hours (56, 57).
2. Casein Protein
Casein is yet another milk protein. Though it is digested slower than whey, it offers the same weight loss benefits.
Casein protein tends to form curds when exposed to acids in your stomach. That makes it more difficult to digest and absorb and may take approximately 6-7 hours. However, this slow digestion rate is what helps you eat less. Casein keeps you feeling full for longer hours and decreases your appetite (58).
One study experimented on casein, whey, egg, and pea protein. They were given 30 minutes before an unrestricted meal. Results showed that casein has the greatest impact on fullness, and resulted in the least number of calories consumed (59).
But of course, there will be contradicting results. Another study showed that people who had whey protein 90 minutes before eating at a buffet were less hungry and ate fewer calories than those who consumed casein (57).
The variation in these results may be due to the timing of consumption. These studies suggest that casein is superior to whey only when consumed 30 instead of 90 minutes before a meal. More studies are needed to compare the two and other types of proteins.
Casein is rich in calcium too! Many studies have linked higher calcium intake to lower body weight (60, 61, 62, 63).
3. Soy Protein
Soy protein is plant-based and contains all 9 essential amino acids important for human health. This is perfect for vegans and those who cannot tolerate milk proteins.
Similar to whey and casein, this too has an effect on appetite. Though whey is known to be the best in reducing appetite and the number of calories consumed, soy is more effective than egg white protein (64).
Soy is beneficial for postmenopausal women too. Drinking 20 grams of soy drink daily for 3 months can help you lose more belly fat (65).
Soy protein is comparable to other types of protein for weight loss when used along with low-calorie meals (66).
4. Egg White Protein
If you cannot take milk proteins, egg white protein makes a good substitute. While an egg’s key nutrients are mostly concentrated in the yolk, egg white protein is made only from whites, hence the name (67).
Dehydrated chicken egg whites are turned into powder. Other brands go into pasteurization to prevent Salmonella and inactivate avidin, a protein that prevents the absorption of biotin (68).
Egg white protein can reduce your appetite, but as mentioned earlier it is not as potent as whey or casein. Still, it helps you consume fewer calories, aiding your weight loss efforts, especially if done on a regular basis.
5. Pea Protein
Similar to soy, pea protein has all 9 essential amino acids, but the quality of its amino composition is not comparable to dairy-based proteins.
It’s hypoallergenic. Hence, suitable for those with allergies or intolerances to milk, eggs, or soy. What’s more, pea protein can also help you lose weight.
Evidence showed that next to casein, pea protein has a strong effect on lowering appetite.
Unfortunately, it does not taste as good as smashed peas. Due to its earthy taste, most brands use flavorings to make it more palatable.
6. Rice Protein
Rice protein is plant-based. It is often called an incomplete protein because it has low levels of lysine. Mixing it with pea protein will give you a more complete and favorable amino acid profile.
While rice protein is not well studied yet, it is suggested that rice protein is as effective as whey in reducing reduce fat mass and increasing lean muscle mass (69).
Nevertheless, more studies are needed to establish the role of rice protein in weight loss.
7. Other Protein Sources
Although lacking scientific evidence, these protein sources are believed to be helpful in weight loss too:
- Hemp Protein: This plant-based protein is rich in healthy omega-3 and omega-6 fatty acids and fiber. However, it is low in the essential amino acids lysine and leucine. Hence cannot be considered a complete protein source (70).
- Bone Broth Protein: Bone broth protein is made by boiling the bones of animals to release nutrients. While it lacks some branched-chain amino acids, it does contain other valuable nutrients.
Key Takeaway
Protein is indeed one of the simplest and most delicious ways to lose weight. Most high-protein foods taste really good, and eating more of them is easy and satisfying.
What’s more, a high-protein diet can be an effective weight-loss strategy in the long-term. It isn’t something that you just use temporarily to slim down.
Protein is effective in boosting your metabolism and reducing hunger, but you should not negate the concept of calorie deficit. Focus on eating whole, single-ingredient foods!
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