Protein is made up of 20 amino acids, the building blocks of muscle. It's the most important macronutrient for lean muscle repair and growth. Proteins are in our tissues, cells, glands, organs, hormones, and even bodily fluids.
Protein can mean many things, but here, we're mainly concerned with dietary protein and how it relates to health, building muscle, and weight loss.
Proteins have a variety of purposes:
Help repair damaged cells, tissues, and structures. It has a hand in the growth and development of nearly every living being.
Gives collagen and keratin in skin, nails, hair, and bone their unique structure.
- Gives collagen in bone and skin its elasticity.
Aids chemical reactions.
Serve as chemical messengers, via hormones.
Regulates vascular system fluid levels.
Helps maintain pH levels in bodily fluids.
Aids the immune system.
Types of supplements
Although we suggest getting a majority of your protein from food, for some people, it can be difficult to get the recommended daily allowance (RDA) without supplementation, especially when trying to build muscle.
This is why we also recommend supplementation:
Whey is found in milk, absorbs quickly, and doesn't stay in your body long, making it a good choice after a rigorous workout.
Thanks to whey's typically high levels of L-leucine, an amino acid, it is anabolic and promotes muscle growth more than other type of protein supplements.
This protein dominates milk, and is a good meal replacement choice. You can also take it before bed. It's slow to absorb and stays in your body longer.
This is a plant-based protein. It's used for meal replacement, as a source of antioxidants, and is easily digestible.
Warning about soy protein
Some studies have shown that soy may affect hormonal balance. Research has also demonstrated that it can lower testosterone levels in men.[16, 17, 18] Because of this, we do not recommend soy protein or soy protein isolate for most individuals.
This fat-free and cholesterol-free protein is found in egg whites. t's also rich in potassium, which aids muscle contraction. Egg protein helps repair muscle after a workout. It absorbs quickly and is easily digestible. Egg protein contains all essential amino acids.
Bulk egg whites are an incredible diet aid. You can purchase bulk egg whites here.
Rice protein comes from brown, white, and whole grain rice, and is easy to digest. Rice protein is packed with nutrients, including essential amino acids, fiber, carbohydrates, and vitamins B and E. It's free of fat, cholesterol, sugar, and salt.
This protein comes from milk and is slow to digest. Over time, it helps build and preserve muscle. Milk protein contains all essential amino acids and includes both whey and casein forms.
This is a highly digestible form of protein powder. It's great for those allergic to whey, casein, or milk. Research shows that pea protein is helpful in maintaining cholesterol and triglyceride levels.[21, 22]
Hemp protein is made by grinding cannabis sativa seeds. Even though hemp and cannabis are from the same plant, hemp is not inebriating. Hemp protein contains all 20 amino acids used by humans, including eight essential aminos,
Hemp protein has a desirable fatty acid ratio, with lots of omega-3 fats, making it healthy for cardiovascular health.
Proteins are the building blocks of muscles, and amino acids are the building blocks of protein.
Essential amino acids
These can't be made by the body, so you need to get them from food. The first three of these are the branched-chain amino acids, or BCAAs. They are the most important amino acids for muscle repair and growth. Of the top three, L-leucine is critical for muscle growth and repair.
The ingredients label on your protein powder should state how much leucine it contains, and it should not be one of the smaller numbers in the amino acid breakdown.
Types of essential amino acids:
Nonessential amino acids
The body makes nonessential amino acids from essential amino acids and from protein breakdown.
Conditional amino acids
These amino acids are essential when illness or stress strike.
Important note about glycine and taurine in your protein
Be wary of protein supplements that include glycine and taurine. Because they're so inexpensive, they're often used to bolster protein content, which will be inflated on the label.
Avoid products that list these as an "added ingredient." It's possible you're being ripped off and not getting the true dietary amount of protein.
The majority of your protein-rich diet comes from healthy food sources, such as those listed here:
Meat, including beef and pork
Poultry, including chicken and turkey
Eggs and egg whites
Dried beans and peas
Nuts and nut butters, such as peanuts, walnuts, almonds, and pistachios
Your daily diet should consist of anywhere from 10% to 40% protein. This is an extremely vague amount because it depends on what your unique dietary needs are and if you're in training or have a regular exercise routine.
For athletes, the amount of protein required depends on your age and reason you're consuming the nutrient. The amount you need will always be based on your weight.
When in doubt, consume 1g of protein per pound of bodyweight each day. As long as you're at a healthy weight, you can't go wrong starting here.
Here are the minimum numbers that experts recommend, some authorities suggest taking amounts as much as 2 to 4 times higher than the minimum RDA:
|Activity level||Amount per pound of bodyweight|
|Recreational||.5g to .75g|
|Competitive||.6g to .9g|
|Building muscle mass||.7g to .9g|
|Teens (active)||.8g to .9g|
Other sources put the general range for protein intake for exercisers at 1.4g to 2g per pound of body weight, with endurance athletes requiring 1g to 1.6g per pound, depending on exercise intensity and duration, plus the athlete's training status. Strength and power athletes need 1.6g to 2g per kilogram.
We highly recommend using a food scale and a calorie counting app to help achieve your goals.
Start with 1g per pound
Again, the safe number for most people is 1g of protein per pound of bodyweight, every day - even rest days. Space it out throughout the day, and get your protein from food and supplement sources. Vary your diet to get a broad range of amino acids.
For a 160-pound male, consuming 175g of protein daily is not as easy as it may seem. Consistency is key. Build your diet around that number. This is where protein supplementation comes in handy.
If you are seeing decent muscle-building results, and want even more, you can add more protein, carbs, and some saturated fats.
The recommended daily allowance (RDA) for the general population are as follows:
|Children (1 to 3 years)||13g|
|Children (4 to 8 years)||19g|
|Children (9 to 13 years)||34g|
|Girls (14 to 18 years)||46g|
|Boys (14 to 18 years)||52g|
|Women (19 to 70+ years)||46g|
|Men (19 to 70+) years: (active)||56g|
Check out nutrition labels and you'll see that it really isn't difficult to get enough protein. People in industrialized countries like the U.S. often end up getting more than they need, especially those who eat a lot of animal protein.[6, 8]
It's the serious athletes and weight loss dieters that really need to focus on getting more of the nutrient.
While we've talked about several benefits above, specifically in terms of building muscle, there are even more.
Protein builds and repairs tissues.
Amino acids provide quick energy when carbohydrates and fats aren't available.
Reducing calorie intake to facilitate weight loss may necessitate higher protein intake since you may not have enough carbohydrates and fat to provide needed energy. Be sure to eat enough complex carbs and healthy fats, which will help prevent protein sparing.
For weight loss
Protein may aid weight loss efforts in the following ways:
Satiety: Protein boosts the feeling of satisfaction (i.e. feeling full) that may reduce total calorie consumption.
Thermogenesis: Thermogenesis is the generation of body heat. Protein tends to increase it, thus, positively affecting satiety and energy expenditure.
Fat-free mass growth and maintenance: Protein promotes slow muscle growth and maintain muscle over time.
But also consider these points:
The key to weight loss, in general, is taking in fewer calories than you burn. However, we are more concerned with fat loss, which requires a shift from processed carbohydrates to natural proteins, fats, and vegetables.
Although replacing a meal here and there with a protein shake may help cut calories and lead to weight loss, if you make a habit of this, you'll be missing out on important micronutrients that whole foods provide.
Protein still contains calories, and consuming too much can lead to weight gain and fat storage.
If you take in more protein than is needed (for energy and making other proteins), excess protein is stored as fat. So don't consume too much protein to help build bigger muscles. It might backfire and cause unwanted weight gain instead.[3, 11]
If you fill up on protein, you may skip eating vegetables and fruits that are also required for optimal health.
Excessive protein consumption may alter hormones and hormonal responses. The hormone leptin plays a role in helping you to curb excess eating.
Stick to a balanced, healthy diet that includes fruits, vegetables, healthy fats, and lean protein, and get regular daily exercise to aid weight loss.
One popular study demonstrated that consuming a whey protein shake before breakfast can promote fat loss, due to its ability to curb appetite, specifically fat-inducing carbohydrates, such as cereal grains.
Deficiency and toxicity
Overconsumption of protein may lead to dehydration since metabolizing the nutrient requires a lot of water. Drink plenty of fluids when eating protein-rich foods or taking protein supplements to help flush byproducts caused by nutrient breakdown.[3, 9]
Happens when you don't get enough protein, or energy in the form of carbohydrates and fats.
Can occur when you don't get enough quality or absorbable protein.
Vegetarians have to be careful not to become protein deficient, as do people who exercise often and restrict calories. Consult a registered dietician if you need help managing your protein intake.[5, 8, 9]
Too much protein can cause kidney function complications, especially in people with kidney difficulties and diabetes. It can also cause excessive calcium loss via urine, which can lead to osteoporosis, especially in women.
Protein powders and shakes
There are many forms of protein powder, but the most common are whey, casein, and soy. Powders provide complete protein. Plus, they're convenient and easy to digest.
The best times to use protein powder are:[4,12]
When starting a new workout regimen, especially with the goal of building muscle
When recovering from an injury
During growth spurts
When you're increasing the intensity of your workout
As you're switching to a vegetarian, vegan, or other protein-limited diet
Protein shakes are available in a variety of combinations containing protein, carbohydrates, and fats. Some have protein while others are high in carbohydrates. They are available in powder form and ready-to-drink, in a variety of flavors and forms. Shakes are often used by athletes following their workouts for the purpose of restoring energy.
Some benefits of protein shakes include helping the body recover from rigorous exercise. Protein can also replenish muscle glycogen stores in endurance athletes and repair muscle damage that occurs during bodybuilding exercises.
It's unnecessary to supplement your diet with protein powders and shakes if you eat a healthy, balanced diet that includes fish, chicken, meat, and dairy.
It's important to separate the side effects of consuming low-quality meat from the side effects of protein. This is a distinction that is often over-looked.
The objection most frequently given for protein supplementation is that it's bad for the kidneys. This is one of those things that is now in the territory of, "If people say it enough, it must be true." This claim is one of the most baseless old wives' tales in the industry.
High protein supplementation led to still-normal clearance rates of creatinine, urea, and albumin. Protein under 2.8g per kg (a whopping 6g of protein per pound of bodyweight!) did not impair renal function in athletes.
A meta-analysis showed that healthy individuals have no adverse reaction to additional amounts of protein. When given extra protein, adaptive processes likely occur in the body, yet are within normal function.
This study essentially states that no research has provided evidence that protein can damage health. However, the meta-review does not prove it's healthy, either. It simply has not shown protein to interfere or damage renal health. Further, it does not recommend any type of dietary restriction.
Here are some facts regarding dietary protein sources:[1, 7, 5]
Excessive meat consumption, especially grass-fed beef, can lead to high cholesterol, gout, and kidney problems. To reduce cholesterol irregularities, limit fatty cuts of meat, processed lunch meats, liver, egg yolks, and duck.
If you are eating whole eggs as a primary protein source, you will be taking in additional cholesterol and fat. Whether or not that is bad for you is debated often.
A diet high in cholesterol can boost LDL "bad" cholesterol levels.
Nuts and seeds are good sources of protein, but steer clear of added salt.
Do not consume whey or casein protein if you have a dairy allergy or intolerance.
Healthy, non-athletic individuals with a proper diet rarely need supplemental protein.[1,2] Be sure to read the label on all protein supplements to make sure they contains the right ingredients in the amount you need or desire.
Where to buy
Protein is expensive, and prices are always rising. You can see product listings here at PricePlow and save from 30% to 50% off retail prices. Plus, be sure to check our price-reduction updates each day.
Best whey proteinThere is no "best protein." In general, we are fans of whey protein and whey protein isolate products.
We especially like MTS Nutrition Whey Protein for regular whey protein. If you're lactose intolerant, we suggest trying IsoFUEL or Dymatize ISO-100.
If you're vegan, vegetarian, or don't eat dairy, consider pea or hemp protein, which we believe are the next two best types of protein.
- "Protein in Diet;" MedlinePlus; Updated May 2012
- Centers for Disease Control and Prevention; "Protein;" Updated October 2012
- Jessica Matthews, M.S.; American Council on Exercise; "Are There Health Risks Concerning Eating Too Much Protein?" December 2009
- Gina Shaw; WebMD; "Do You Need Protein Powders?" 2011
- WebMD; "Protein Shakes;" 2012
- Louise Chang, MD; WebMD; "How Much Protein Do You Need?" 2011
- ChooseMyPlate.gov; "Why is it Important to Make Lean or Low-Fat Choices from the Protein Foods Group?"
- Rankin JW; Clinics in Sports Medicine; "Role of Protein in Exercise;" 1999
- Paul Insel, "Nutrition;" Fourth Edition, 2011
- Michael A. Clark, et. al.; "NASM Essentials of Personal Fitness Training;" Third Edition, 2008
- Neil Osterweil; WebMD; "The Benefits of Protein"
- Montana State University; "Sports Nutrition: Protein Goals"
- Dustin Bogle; Livestrong.com; "What are the Benefits of Egg Protein;" 2010
- Benjamin Small; Livestrong.com; "What are the Benefits of Rice Protein Powder?" 2010
- National Dairy Council; "Dairy Protein Benefits for Physically Active People;" 2008
- Goodin S, et. al.; Cancer Epidemiology, Biomarkers and Prevention; "Clinical and Biological Activity of Soy Protein Powder Supplementation in Healthy Male Volunteers;" April 2007
- Hamilton-Reeves JM, et. al.; Fertility and Sterility; "Clinical Studies Show No Effects of Soy Protein or Isoflavones on Reproductive Hormones in Men: Results of a Meta-Analysis;" August 2010
- Messina M; Fertility and Sterility; "Soybean Isoflavone Exposure does not have Feminizing Effects on Men: A Critical Examination of the Clinical Evidence;" May 2010
- Katherine Zeratsky, RD, LD; Mayo Clinic; "Protein Shakes: Good for Weight Loss?" 2012