Facebook Twitter

Macronutrients 2 of 3: Protein

Protein provides the structure for all living things. After water, protein accounts for the greatest portion of human body weight. A typical person is 60% water, 20% protein and most of the rest minerals (like the calcium in bones).

What is protein?

All proteins are a chain of amino acids. An amino acid is a small molecule that acts as the building block of any cell. Amino acids get their name from their chemical structure. They all contain an amino group (NH2) and a carboxyl group (COOH), which is acidic. Below are examples of two essential amino acids.

Notice that one section is identical in all amino acids.
It is the variable part that distinguishes one from another.
Threonine Highlighted
Methionine Highlighted

What are the differences between amino acids?

Amino acids are divided into ESSENTIAL and NON-ESSENTIAL groups. A non-essential amino acid is one your body can create out of other chemicals in your body. The essential amino acids cannot be created, so the only way to get them is through food. Your body links these amino acids into thousands of different ways to form thousands of proteins. Each protein plays a unique function in the body.

There is a third group that we will call conditionally essential amino acids.

A conditionally essential amino acid is one that must be supplied from outside sources to people who are unable to synthesize it in adequate amounts. For example, people who have the disease phenylketonuria (or PKU) must keep their intake of phenylalanine extremely low to avoid problems. Unfortunately, phenylalanine is required for our bodies to synthesize tyrosine. So if you suffer from PKU, tyrosine from an outside source is an essential amino acid.

Conditionally essential amino acids are Arginine, Cysteine, Glycine, Glutamine, Proline, Serine and Tyrosine.

How does my body use protein?

When you eat protein, your digestive system breaks it down into shorter amino acid chains (polypeptides and then peptides), so they can enter your bloodstream. Cells then use the amino acids as building blocks.

How much protein should I take in every day?

The Reference Daily Intake set by the Food and Nutrition Board for protein is 0.36 grams of protein per pound of your LEAN or IDEAL body weight. That means a 180-pound person would need to take in approximately 65 grams of protein. But that's not the final word.

ENDURANCE TRAINING can dramatically increase the required amounts. .55 to .64 grams of protein per pound of your LEAN or IDEAL body weight per day.

STRENGTH TRAINING bumps it up even further. .73 to .78 grams of protein per pound of your LEAN or IDEAL body weight per day.

If you're a VEGETARIAN, it is suggested you increase your protein intake above recommended levels by approximately 10%. The increase is because plant proteins are considered lower quality, and they don't have as many of the essential amino acids that animal proteins do. The 10% increase is to make up for those deficiencies. (There is one exception. Soy protein is the one vegetable protein that does contain all the essential amino acids.)

PREGNANT WOMEN generally need an extra 10 grams of protein per day above suggested levels. WOMEN WHO ARE NURSING typically need 15 grams a day extra the first six months, dropping to 12 grams a day extra the second six months.

Supplement companies suggest much higher levels of protein consumption, from 1 to 2 grams of protein per pound of body weight per day. Unfortunately, these higher levels are based on anecdotal evidence and not controlled clinical trials.

How much protein is too much?

Medical research suggests that if more than 35% of your total daily calories are protein, you're probably eating too much. Excess protein can't be stored in the body (like fat and carbs), so eating too much can put a strain on the kidneys and liver.

What foods have protein in them?

We get protein from animal and vegetable sources. Animal sources are typically considered "complete proteins" because they contain all of the essential amino acids. Examples include: Eggs, Meat and Milk.

Vegetable sources do contain proteins, but most are low or missing some of the essential amino acids. If you're a vegan or vegetarian, the key is combining different foods so you can get all the essential amino acids required daily. Examples include: Beans, Nuts and Soybeans.

Protein Sources:

Fish & Seafood
Fish & Seafood: It has heart-healthy omega-3 fatty acids and generally less fat than other meats.

Milk, Cheese & Yogurt
Milk, Cheese & Yogurt: All good sources of protein and calcium. Choose skim or low-fat versions.

Eggs: Ditch the yolks, and you've got a cheap and fat-free source of protein.

White-Meat Poultry
White-Meat Poultry: Remove the skin, and you get rid of most of the saturated (bad) fat. Choose white meat when possible because the dark meat is higher in fat.

Beans: Kidney, pinto, garbanzo and lentil are excellent sources of protein and fiber.

Nuts: One ounce of broiled ribeye steak and one ounce of almonds both contain about the same protein, 6 grams each. Choose dry roasted without salt.

Whole Grains
Whole Grains: 1 Slice of whole wheat bread can have 3 grams of protein plus healthy fiber. Skip traditional butter and spray with fat-free "buttery sprays."

Lean Beef
Lean Beef: A good source of protein and an excellent source of zinc, iron and vitamin B12. Trim away any visible fat before cooking.

Protein Shakes or Bars
Soy: Soy protein contains all the essential amino acids.

What are the different Proteins listed on supplements?

Egg (Ovalbumen) protein is from egg whites. This has long been considered the best source of protein for supplements because of its excellent amino acid profile.

Whole Egg protein has many of the same attributes of egg white protein, but with extra calories and fat.

Soy is the highest quality vegetable protein extracted from soybeans. It has also been shown to enhance fat loss more effectively than casein and may help reduce cholesterol levels.

SOY NOTE: It has been widely reported that soy contains phytoestrogens (isoflavones) that can interfere with muscle hypertrophy. A study published in the 2007 issue of Cancer Epidemiology Biomarkers and Prevention showed a decrease in testosterone levels and an increase in estrogen for the study participants.

Unfortunately, the study was flawed. One of the subjects started with a testosterone level that was 200% higher than the other subjects average levels, and he experienced a steady drop during the study. Those levels indicate a subject coming down off anabolic steroids. Remove him from the study, and there was no such dramatic decrease in the overall participants. The inability of the researchers to remove him from the study show a lack of detail that calls into question the overall results.

Until tests show otherwise, soy protein should be considered as viable a choice for protein supplementation as any other protein source.

Dairy Proteins (Casein and Whey)

Casein protein makes up about 80% of the protein in milk. When milk is curdled, the casein represents the curd. Casein is called a slow protein because it's digested more slowly. This high-quality protein is great for meals throughout the day. Casein is also used at night to slow the rate muscles break down (known as catabolism) while sleeping.

Whey protein makes up about 20% of the protein in milk. When milk is curdled, the whey ends up as a separate liquid. Whey protein is called a fast protein because it's digested rapidly. Whey protein is recommended first thing in the morning, after exercise or anytime you need a quick burst of amino acids because of its rapid uptake. Whey protein may help increase levels of glutathione (GSH), your body's primary antioxidant-fighting mechanism.

Protein Rankings  |  WeBeFit.com Quick Card (c) 2006
Egg White (Ovalbumen) Dairy
Whole Egg Soy
Highest Quality for Muscle Hypertrophy Slow Digesting Protein Fast Digesting Protein High-Quality Protein - BUT Higher Levels of Fat Highest Quality Vegetable Protein - BUT can inhibit Muscle Hypertrophy
Green - Best Choice | Yellow - Proceed with Caution | Red - Avoid

Protein Products and Process of Extraction

Calcium/Sodium/Potassium Caseinate - Protein is extracted from casein through acidification with alkaline substances like calcium, sodium or potassium. Avoid Sodium Caseinate if you're trying to cut sodium levels, and look for Calcium Caseinate if you need more calcium.

Micellar Casein - Microfiltration is the process used to separate the casein portion of milk from the lactose, fat and whey. Micellar Casein isn't denatured (meaning not altered or treated with heat or acid).

Hydrolyzed Casein Protein - Formed by the Hydrolysis of casein.

Whole Milk Protein - The protein is extracted through filtration to remove much of the carbs and fat.

Milk Protein Concentrate - Typically produced through ultrafiltration, this has a protein content of around 80% and contains both the whey and casein fractions of milk.

Milk Protein Isolate - A product of both casein and whey products extracted through an ultrafiltration process. The protein content can be 85% or higher.

Whey Protein Concentrate - Through ultrafiltration and microfiltration, microscopic filters are used to physically separate the protein from fat, carbohydrates, lactose and other materials in milk. This can be sourced at 70%-80% protein per final product.

Whey Protein Isolate - Take Whey Protein Concentrate and process it further through longer filtering or ion exchange, and you end up with Whey Protein Isolate. The protein content is 90% or higher.

Whey Protein Hydrolysate - This is Whey Protein Isolate taken through one additional step, hydrolysis. This is the fastest absorbing of the whey proteins.

Whey Protein Isolate Microfiltration - Whey protein concentrate taken one step further by separating the proteins using natural ceramic filters. This can be sourced up to 92% protein per final product.

Whey Protein Isolate Ion Exchange - In a process called ion exchange, milk is put through a static electrical charge that separates the whey from the lactose and fat. This can be sourced as high as 96% protein per final product.

Whey Protein Isolate Cold Filtration - Proteins are separated through the use of micro filtering in a cold environment. The reason for the chilling is to preserve the undenatured proteins. (Undenatured means - To prevent the tertiary structure of a protein from unfolding so that its original properties, especially its biological activity, aren't diminished or eliminated.) This can be sourced at 35%-80% protein per final product.

Protein Processing Terms

Cross-Flow Microfiltration - Whey protein is separated from fat and lactose with ceramic filters in a low-temperature process. (This is the same process as Microfiltration.)

Hydrolysis - This is a process where protein is predigested into peptides (small chains of amino acids). The theory is that it helps you absorb the protein more efficiently. We emphasize that it's a theory because it's based on a study where the protein was supplied to patients' intestines via a tube. Proteins being marketed as superior because of this process lack clinical proof.

SPECIAL NOTE: Many supplement companies quote the "Boirie et al 1997" study to prove their protein is superior. Read the Abstract for yourself to find out exactly what the study found. Click Here for the study.

Ion Exchange - Ionically charged resins and chemicals such as hydrochloric acid and sodium hydroxide are used to separate protein.

Microfiltration - Whey protein is separated from fat and lactose with ceramic filters in a low-temperature process. (This is the same process as Cross-Flow Microfiltration.)

Ultrafiltration - Pressure and a porous membrane are used to separate the fat and lactose from milk proteins.

Common Protein Rating Systems

(Amino Acid Score) A chemical technique that measures the indispensable amino acids present in a protein and compares the values with a reference protein. The protein is rated based upon the most limiting indispensable amino acid.
(Protein Digestibility Corrected Amino Acid Score) A proteins Amino Acid Score (AAS) with an additional digestibility component. This is the most commonly accepted measure of protein quality because it closely compares to determinations done with animals.
(PLEASE NOTE: Proteins with AAS or PDCAAS values exceeding 1.0 are not considered to contribute additional benefits and are leveled to 1.0. There is some debate about this because some nutritionists feel by rounding down, it fails to reflect a higher quality proteins' ability to complement the nutritional value of a lower quality protein.)
(Protein Efficiency Ratio) Calculated by the amount of weight gained per gram of protein ingested. This test is generally performed on lab animals, typically a weaning rat. PER measures growth but not maintenance, so it may be of limited efficacy when used to determine the protein needs of adults.
(Net Protein Utilization) Measures how well the body uses nitrogen in protein consumed for tissue formation as compared to the amount of nitrogen digested.
(Biological Value) A measure of how well the body retains nitrogen as compared to the amount absorbed.

(PLEASE NOTE: NPU and BV methods of measurement reflect both availability and digestibility. Both methods give an accurate appraisal of maintenance needs.)

The Bottom Line

There is a raging debate going on about what protein is "better" for bodybuilders. We at WeBeFit choose not to pick any protein over any other simply because the research is not conclusive. Until long-term clinical trials are conducted, we suggest you consume proteins from all the major sources. Don't be taken in by the supplement company "advertorials."

Contrary to popular myth, extra protein alone does NOT help build more muscle. Only exercise can help you build muscle.

We would also like to point out that there is no research proving that protein supplements are any better than eating protein-rich foods. Taking protein supplements are a matter of convenience when protein-laden foods are unavailable, inconvenient, or to boost protein calories without a corresponding increase in fat and carbohydrates.

Part 1 2 3

Call for a FREE Consultation (305) 296-3434
CAUTION: Check with your doctor before
beginning any diet or exercise program.

Updated 4/15/2006
Updated 9/9/2009
Updated 5/26/2011
Updated 2/23/2015