Whey Protein: What You Need to Know

Muscular man flexing back, arm, and shoulder.
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­Little Miss Muffett

Sat on a tuffet,


Eating her curds and whey.

Along came a spider

Who sat down beside her

And said, "Hey, nice pecs!"

Today's consumer of whey protein is more likely to be a bodybuilder than the arachnophobic heroine of a nursery rhyme. But the food is the same -- sort of. Curds and whey were probably something like cottage cheese. Whey protein is a nutritional supplement that comes from milk. It's isolated from the rest of the milk through various purification processes.

Only 20 percent of milk's protein is whey. The rest is casein (itself an ingredient of many other protein supplements). Casein is the protein that triggers most milk allergies, so whey protein -- if it's relatively pure -- may be a way for people with allergies to get dairy proteins into their diets. However, it can still set off some allergic reactions, and it can trigger lactose intolerance as well, so proceed with caution.

­The makers of nutritional supplements tout whey protein as a way to build lean muscle mass, recover from workouts and lose weight. Some doctors urge caution, though. No one questions that whey protein can be an effective source of dietary protein, but do you need it at all? And what happens if you don't need it and consume it anyway?

This article will tell you a bit more about whey protein, which could offer benefits to weightlifters and dieters alike. But it can cause some side effects that are a bit scarier than spiders. Read on.







Whey Protein at Work in Your Body

­is vital to your body's function. It helps your cells grow, replace themselves and repair themselves. In fact, protein is a component of every major body system and every fluid except bile and urine.

Your body makes some proteins on its own, from the 12 amino acids it can produce. The other nine amino acids you must get from dietary protein. Whey protein is one such source, and it provides all nine amino acids. Basically, it works in your body the same way, say, a steak does.


However, you absorb whey protein much faster than you would absorb a steak. The faster your body gets the protein, the more quickly it can start building new muscle. And most whey protein is low-fat or fat-free, whereas a steak is not.

The amount of protein the body needs depends on the body. Opinions vary as to how best to calculate it, but you should take into account your body weight, your body fat composition, your activity level and your nutritional goals. A good rule of thumb is 0.8 grams of protein for every kilogram of body weight (.08 g per 2.2 pounds) -- but 150 percent to 200 percent of that amount if you're an athlete in training [source: Definition of Wellness].

What if you consume more than that? The protein you don't need doesn't get stored as muscle-in-waiting. Your body breaks it down into amino acids, then into fatty acids and sugars. These chemicals travel to the liver, which converts them into cholesterol and fat.

Read on for a look at the potential benefits of whey protein.


Whey Protein Benefits


­For people experiencing significant growth -- children, adolescents, pregnant women -- protein is important. These bodies aren't just maintaining, they're producing.


Similarly, athletes use a lot of protein as well -- the process of building muscle is one of constantly tearing and repairing skeletal muscle cells. In fact, you can't build muscle without what's called a "positive protein balance." That means your protein synthesis -- your production of protein -- must be greater than the destruction of muscle the exercise causes. To boost protein synthesis, some physicians recommend consuming protein after a workout.

For athletes -- and the people who want to look like them -- the form of that protein can be important. A two-tablespoon serving of peanut butter could be a great post-workout snack -- but it comes loaded with about 18 grams of fat [source: Peanut Institute]. If you're trying to lose weight, maintain your heart health or achieve lean bodybuilder-style definition, the fat, cholesterol and calories associated with many forms of protein could be a problem.

That's why some people turn to supplements. Whey protein isolate is fat-free, and it's filling. It also has a very high biological value, or BV. BV is a measure of the body's ability to absorb a protein. The naturally occurring protein source with the highest BV is an egg, with a BV of 100. Whey protein is around 104 -- its score can vary depending on its form [source: Whey Protein]. Basically, whey protein is pure, no-frills protein, designed to be absorbed thoroughly and quickly. The speed of absorption matters because it affects the anabolic, or muscle-building, qualities of the protein.

A high-protein, no-fat supplement sounds like it packs a pretty strong one-two punch. Before you get too excited, though, better learn about the side effects.


Whey Protein Side Effects


­Imagine if your bodybuilding regimen led to your not being able to exercise at all. That can happen if you develop gout. Gout is a form of arthritis caused by the buildup of hard, painful crystals of uric acid in the muscles, joints and tendons of the legs and feet. The crystals lead to inflammation, stiffness and tenderness. Attacks can be sudden (most commonly at night, in the big toes) and last for hours or weeks. The pain can be severe and can do lasting damages to the joints. Aspirin only makes it worse. People diagnosed with gout may wind up on maintenance drugs -- or low-meat, no-beer diets -- for the rest of their lives.


Why do people develop gout? There are a variety of causes, but many are related to diet. One of the chief culprits is excess protein, because uric acid is produced when we metabolize protein. (As if that risk weren't enough, synthetic diuretics -- favored by bodybuilders to shed water weight before competitions -- can also be a cause.) If you need any proof of gout's relation to excess, look no further than its most famous sufferer: King Henry VIII.

The joints and muscles aren't the only things affected by too much protein. Your kidneys and liver -- the organs that help your body deal with toxins and waste -- have to work overtime to handle all the amino acids you can't use. Over time, that can cause kidney problems and lasting damage, such as kidney stones. Even some protein supplement vendors advise customers not to go overboard.

As noted before, what constitutes "too much protein" depends on your body and your activity level. Men typically need more protein than women do. Athletes need more than sedentary people do. To avoid side effects, just plan your protein consumption carefully. Your doctor can help.

OK -- side effects, schmide effects. People who have put up with nausea, hunger pangs and headaches really just want to know one thing: Will this stuff help me lose weight? Read on.


Whey Protein and Weight Loss


­In a study funded by a whey protein manufacturer, clinically obese people who used whey protein as part of a calorie-reduction program lost about the same amount of weight as people who cut out the same number of calories but didn't use whey protein. The difference was in the kind of weight they lost. The people who used whey protein lost body fat, not muscle [source: Frestedt].


Being able to lose weight but hang onto lean muscle has some important health implications. For one thing, your base metabolism is higher if you have a higher muscle-to-fat ratio. Your bone density may be better (low bone density is often a problem for women who have lost weight by dieting). Your hormone levels may shift, improving your body's ability to regulate its own weight. Research with rats indicates that a whey protein diet may help reduce insulin resistance, a condition -- often a precursor to diabetes -- in which normal levels of insulin are no longer adequate for metabolism [source: Belobradjic].

Of course, rats aren't the same as people, and one study is not the same thing as a law of nature. There are almost as many ideas about weight-loss regimens as there are nutritionists. Proponents of whey protein tend to fall into the camp of high-protein, low-carb weight-loss plans, such as Atkins and the South Beach Diet. Opponents of whey protein tend to be the folks who tout whole foods and vegetarianism.

Isn't it possible that, if you're taking whey protein to build muscle, it might actually lead to weight gain rather than weight loss? Fair question. And the answer is yes, it's completely possible. Whey protein is a component of many weight-gain regimens.

If you don't reduce your calories but add whey protein to the mix, you probably will gain weight. However, if you don't exercise, there's no way that whey protein will magically turn into muscle. The body will do what it does with every excess nutrient: make fat.

Sound dietary planning and physical activity remain the cornerstones of any weight loss program. Neither whey protein nor any other supplement is going to lose the weight for you. You still have to do the work. However, doing it with whey protein could be an option.

To learn more, visit the links on the next page.


Lots More Information

Related HowStuffWorks Articles


  • Appleby, Maia. "Does Excess Protein Turn Into Fat? An Anatomy Lesson." Nutrition InfoCenter. 2009. (Accessed 3/23/09) http://www.1stholistic.com/Nutrition/hol_nutr_does-excess-protein-turn-to-fat.htm
  • Belobradjic, Damien P.; McIntosh, Graeme H.; Owens, Julie A. "A High-Whey-Protein Diet Reduces Body Weight Gain and Alters Insulin Sensitivity Relative to Red Meat in Wistar Rats." Journal of Nutrition. 2004. (Accessed 3/22/09) http://jn.nutrition.org/cgi/content/abstract/134/6/1454
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  • The Peanut Institute. "High Monounsaturated Fat Diets vs. Low-Fat Diets." (Accessed 3/22/09) http://www.peanut-institute.org/Saturated_UnsaturatedFFT.html
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